Home | History | Annotate | Line # | Download | only in time
      1 News for the tz database
      2 
      3 Release 2025b - 2025-03-22 13:40:46 -0700
      4 
      5   Briefly:
      6     New zone for Aysn Region in Chile which moves from -04/-03 to -03.
      7 
      8   Changes to future timestamps
      9 
     10     Chile's Aysn Region moves from -04/-03 to -03 year-round, joining
     11     Magallanes Region.  The region will not change its clocks on
     12     2025-04-05 at 24:00, diverging from America/Santiago and creating a
     13     new zone America/Coyhaique.  (Thanks to Yonathan Dossow.)  Model
     14     this as a change to standard offset effective 2025-03-20.
     15 
     16   Changes to past timestamps
     17 
     18     Iran switched from +04 to +0330 on 1978-11-10 at 24:00, not at
     19     year end.  (Thanks to Roozbeh Pournader.)
     20 
     21   Changes to code
     22 
     23     'zic -l TIMEZONE -d . -l /some/other/file/system' no longer
     24     attempts to create an incorrect symlink, and no longer has a
     25     read buffer underflow.  (Problem reported by Evgeniy Gorbanev.)
     26 
     27 
     28 Release 2025a - 2025-01-15 10:47:24 -0800
     29 
     30   Briefly:
     31     Paraguay adopted permanent -03 starting spring 2024.
     32     Improve pre-1991 data for the Philippines.
     33     Etc/Unknown is now reserved.
     34 
     35   Changes to future timestamps
     36 
     37     Paraguay stopped changing its clocks after the spring-forward
     38     transition on 2024-10-06, so it is now permanently at -03.
     39     (Thanks to Heitor David Pinto and Even Scharning.)
     40     This affects timestamps starting 2025-03-22, as well as the
     41     obsolescent tm_isdst flags starting 2024-10-15.
     42 
     43   Changes to past timestamps
     44 
     45     Correct timestamps for the Philippines before 1900, and from 1937
     46     through 1990.  (Thanks to P Chan for the heads-up and citations.)
     47     This includes adjusting local mean time before 1899; fixing
     48     transitions in September 1899, January 1937, and June 1954; adding
     49     transitions in December 1941, November 1945, March and September
     50     1977, and May and July 1990; and removing incorrect transitions in
     51     March and September 1978.
     52 
     53   Changes to data
     54 
     55     Add zone1970.tab lines for the Concordia and Eyre Bird Observatory
     56     research stations.  (Thanks to Derick Rethans and Jule Dabars.)
     57 
     58   Changes to code
     59 
     60     strftime %s now generates the correct numeric string even when the
     61     represented number does not fit into time_t.  This is better than
     62     generating the numeric equivalent of (time_t) -1, as strftime did
     63     in TZDB releases 96a (when %s was introduced) through 2020a and in
     64     releases 2022b through 2024b.  It is also better than failing and
     65     returning 0, as strftime did in releases 2020b through 2022a.
     66 
     67     strftime now outputs an invalid conversion specifier as-is,
     68     instead of eliding the leading '%', which confused debugging.
     69 
     70     An invalid TZ now generates the time zone abbreviation "-00", not
     71     "UTC", to help the user see that an error has occurred.  (Thanks
     72     to Arthur David Olson for suggesting a "wrong result".)
     73 
     74     mktime and timeoff no longer incorrectly fail merely because a
     75     struct tm component near INT_MIN or INT_MAX overflows when a
     76     lower-order component carries into it.
     77 
     78     TZNAME_MAXIMUM, the maximum number of bytes in a proleptic TZ
     79     string's time zone abbreviation, now defaults to 254 not 255.
     80     This helps reduce the size of internal state from 25480 to 21384
     81     on common platforms.  This change should not be a problem, as
     82     nobody uses such long "abbreviations" and the longstanding tzcode
     83     maximum was 16 until release 2023a.  For those who prefer no
     84     arbitrary limits, you can now specify TZNAME_MAXIMUM values up to
     85     PTRDIFF_MAX, a limit forced by C anyway; formerly tzcode silently
     86     misbehaved unless TZNAME_MAXIMUM was less than INT_MAX.
     87 
     88     tzset and related functions no longer leak a file descriptor if
     89     another thread forks or execs at about the same time and if the
     90     platform has O_CLOFORK and O_CLOEXEC respectively.  Also, the
     91     functions no longer let a TZif file become a controlling terminal.
     92 
     93     'zdump -' now reads TZif data from /dev/stdin.
     94     (From a question by Arthur David Olson.)
     95 
     96   Changes to documentation
     97 
     98     The name Etc/Unknown is now reserved: it will not be used by TZDB.
     99     This is for compatibility with CLDR, which uses the string
    100     "Etc/Unknown" for an unknown or invalid timezone.  (Thanks to
    101     Justin Grant, Mark Davis, and Guy Harris.)
    102 
    103     Cite Internet RFC 9636, which obsoletes RFC 8536 for TZif format.
    104 
    105 
    106 Release 2024b - 2024-09-04 12:27:47 -0700
    107 
    108   Briefly:
    109     Improve historical data for Mexico, Mongolia, and Portugal.
    110     System V names are now obsolescent.
    111     The main data form now uses %z.
    112     The code now conforms to RFC 8536 for early timestamps.
    113     Support POSIX.1-2024, which removes asctime_r and ctime_r.
    114     Assume POSIX.2-1992 or later for shell scripts.
    115     SUPPORT_C89 now defaults to 1.
    116 
    117   Changes to past timestamps
    118 
    119     Asia/Choibalsan is now an alias for Asia/Ulaanbaatar rather than
    120     being a separate Zone with differing behavior before April 2008.
    121     This seems better given our wildly conflicting information about
    122     Mongolia's time zone history.  (Thanks to Heitor David Pinto.)
    123 
    124     Historical transitions for Mexico have been updated based on
    125     official Mexican decrees.  The affected timestamps occur during
    126     the years 1921-1927, 1931, 1945, 1949-1970, and 1981-1997.
    127     The affected zones are America/Bahia_Banderas, America/Cancun,
    128     America/Chihuahua, America/Ciudad_Juarez, America/Hermosillo,
    129     America/Mazatlan, America/Merida, America/Mexico_City,
    130     America/Monterrey, America/Ojinaga, and America/Tijuana.
    131     (Thanks to Heitor David Pinto.)
    132 
    133     Historical transitions for Portugal, represented by Europe/Lisbon,
    134     Atlantic/Azores, and Atlantic/Madeira, have been updated based on a
    135     close reading of old Portuguese legislation, replacing previous data
    136     mainly originating from Whitman and Shanks & Pottenger.  These
    137     changes affect a few transitions in 1917-1921, 1924, and 1940
    138     throughout these regions by a few hours or days, and various
    139     timestamps between 1977 and 1993 depending on the region.  In
    140     particular, the Azores and Madeira did not observe DST from 1977 to
    141     1981.  Additionally, the adoption of standard zonal time in former
    142     Portuguese colonies have been adjusted: Africa/Maputo in 1909, and
    143     Asia/Dili by 22 minutes at the start of 1912.
    144     (Thanks to Tim Parenti.)
    145 
    146   Changes to past tm_isdst flags
    147 
    148     The period from 1966-04-03 through 1966-10-02 in Portugal is now
    149     modeled as DST, to more closely reflect how contemporaneous changes
    150     in law entered into force.
    151 
    152   Changes to data
    153 
    154     Names present only for compatibility with UNIX System V
    155     (last released in the 1990s) have been moved to 'backward'.
    156     These names, which for post-1970 timestamps mostly just duplicate
    157     data of geographical names, were confusing downstream uses.
    158     Names moved to 'backward' are now links to geographical names.
    159     This affects behavior for TZ='EET' for some pre-1981 timestamps,
    160     for TZ='CET' for some pre-1947 timestamps, and for TZ='WET' for
    161     some pre-1996 timestamps.  Also, TZ='MET' now behaves like
    162     TZ='CET' and so uses the abbreviation "CET" rather than "MET".
    163     Those needing the previous TZDB behavior, which does not match any
    164     real-world clocks, can find the old entries in 'backzone'.
    165     (Problem reported by Justin Grant.)
    166 
    167     The main source files' time zone abbreviations now use %z,
    168     supported by zic since release 2015f and used in vanguard form
    169     since release 2022b.  For example, America/Sao_Paulo now contains
    170     the zone continuation line "-3:00 Brazil %z", which is less error
    171     prone than the old "-3:00 Brazil -03/-02".  This does not change
    172     the represented data: the generated TZif files are unchanged.
    173     Rearguard form still avoids %z, to support obsolescent parsers.
    174 
    175     Asia/Almaty has been removed from zonenow.tab as it now agrees
    176     with Asia/Tashkent for future timestamps, due to Kazakhstan's
    177     2024-02-29 time zone change.  Similarly, America/Scoresbysund
    178     has been removed, as it now agrees with America/Nuuk due to
    179     its 2024-03-31 time zone change.
    180 
    181   Changes to code
    182 
    183     localtime.c now always uses a TZif file's time type 0 to handle
    184     timestamps before the file's first transition.  Formerly,
    185     localtime.c sometimes inferred a different time type, in order to
    186     handle problematic data generated by zic 2018e or earlier.  As it
    187     is now safe to assume more recent versions of zic, there is no
    188     longer a pressing need to fail to conform RFC 8536 section 3.2,
    189     which requires using time type 0 in this situation.  This change
    190     does not affect behavior when reading TZif files generated by zic
    191     2018f and later.
    192 
    193     POSIX.1-2024 removes asctime_r and ctime_r and does not let
    194     libraries define them, so remove them except when needed to
    195     conform to earlier POSIX.  These functions are dangerous as they
    196     can overrun user buffers.  If you still need them, add
    197     -DSUPPORT_POSIX2008 to CFLAGS.
    198 
    199     The SUPPORT_C89 option now defaults to 1 instead of 0, fixing a
    200     POSIX-conformance bug introduced in 2023a.
    201 
    202     tzselect now supports POSIX.1-2024 proleptic TZ strings.  Also, it
    203     assumes POSIX.2-1992 or later, as practical porting targets now
    204     all support that, and it uses some features from POSIX.1-2024 if
    205     available.
    206 
    207   Changes to build procedure
    208 
    209     'make check' no longer requires curl and Internet access.
    210 
    211     The build procedure now assumes POSIX.2-1992 or later, to simplify
    212     maintenance.  To build on Solaris 10, the only extant system still
    213     defaulting to pre-POSIX, prepend /usr/xpg4/bin to PATH.
    214 
    215   Changes to documentation
    216 
    217     The documentation now reflects POSIX.1-2024.
    218 
    219   Changes to commentary
    220 
    221     Commentary about historical transitions in Portugal and her former
    222     colonies has been expanded with links to relevant legislation.
    223     (Thanks to Tim Parenti.)
    224 
    225 
    226 Release 2024a - 2024-02-01 09:28:56 -0800
    227 
    228   Briefly:
    229     Kazakhstan unifies on UTC+5 beginning 2024-03-01.
    230     Palestine springs forward a week later after Ramadan.
    231     zic no longer pretends to support indefinite-past DST.
    232     localtime no longer mishandles Ciudad Jurez in 2422.
    233 
    234   Changes to future timestamps
    235 
    236     Kazakhstan unifies on UTC+5.  This affects Asia/Almaty and
    237     Asia/Qostanay which together represent the eastern portion of the
    238     country that will transition from UTC+6 on 2024-03-01 at 00:00 to
    239     join the western portion.  (Thanks to Zhanbolat Raimbekov.)
    240 
    241     Palestine springs forward a week later than previously predicted
    242     in 2024 and 2025.  (Thanks to Heba Hamad.)  Change spring-forward
    243     predictions to the second Saturday after Ramadan, not the first;
    244     this also affects other predictions starting in 2039.
    245 
    246   Changes to past timestamps
    247 
    248     Asia/Ho_Chi_Minh's 1955-07-01 transition occurred at 01:00
    249     not 00:00.  (Thanks to on Trn Cng Danh.)
    250 
    251     From 1947 through 1949, Toronto's transitions occurred at 02:00
    252     not 00:00.  (Thanks to Chris Walton.)
    253 
    254     In 1911 Miquelon adopted standard time on June 15, not May 15.
    255 
    256   Changes to code
    257 
    258     The FROM and TO columns of Rule lines can no longer be "minimum"
    259     or an abbreviation of "minimum", because TZif files do not support
    260     DST rules that extend into the indefinite past - although these
    261     rules were supported when TZif files had only 32-bit data, this
    262     stopped working when 64-bit TZif files were introduced in 1995.
    263     This should not be a problem for realistic data, since DST was
    264     first used in the 20th century.  As a transition aid, FROM columns
    265     like "minimum" are now diagnosed and then treated as if they were
    266     the year 1900; this should suffice for TZif files on old systems
    267     with only 32-bit time_t, and it is more compatible with bugs in
    268     2023c-and-earlier localtime.c.  (Problem reported by Yoshito
    269     Umaoka.)
    270 
    271     localtime and related functions no longer mishandle some
    272     timestamps that occur about 400 years after a switch to a time
    273     zone with a DST schedule.  In 2023d data this problem was visible
    274     for some timestamps in November 2422, November 2822, etc. in
    275     America/Ciudad_Juarez.  (Problem reported by Gilmore Davidson.)
    276 
    277     strftime %s now uses tm_gmtoff if available.  (Problem and draft
    278     patch reported by Dag-Erling Smrgrav.)
    279 
    280   Changes to build procedure
    281 
    282     The leap-seconds.list file is now copied from the IERS instead of
    283     from its downstream counterpart at NIST, as the IERS version is
    284     now in the public domain too and tends to be more up-to-date.
    285     (Thanks to Martin Burnicki for liaisoning with the IERS.)
    286 
    287   Changes to documentation
    288 
    289     The strftime man page documents which struct tm members affect
    290     which conversion specs, and that tzset is called.  (Problems
    291     reported by Robert Elz and Steve Summit.)
    292 
    293 
    294 Release 2023d - 2023-12-21 20:02:24 -0800
    295 
    296   Briefly:
    297     Ittoqqortoormiit, Greenland changes time zones on 2024-03-31.
    298     Vostok, Antarctica changed time zones on 2023-12-18.
    299     Casey, Antarctica changed time zones five times since 2020.
    300     Code and data fixes for Palestine timestamps starting in 2072.
    301     A new data file zonenow.tab for timestamps starting now.
    302 
    303   Changes to future timestamps
    304 
    305     Ittoqqortoormiit, Greenland (America/Scoresbysund) joins most of
    306     the rest of Greenland's timekeeping practice on 2024-03-31, by
    307     changing its time zone from -01/+00 to -02/-01 at the same moment
    308     as the spring-forward transition.  Its clocks will therefore not
    309     spring forward as previously scheduled.  The time zone change
    310     reverts to its common practice before 1981.  (Thanks to Jule Dabars.)
    311 
    312     Fix predictions for DST transitions in Palestine in 2072-2075,
    313     correcting a typo introduced in 2023a.  (Thanks to Jule Dabars.)
    314 
    315   Changes to past and future timestamps
    316 
    317     Vostok, Antarctica changed to +05 on 2023-12-18.  It had been at
    318     +07 (not +06) for years.  (Thanks to Zakhary V. Akulov.)
    319 
    320     Change data for Casey, Antarctica to agree with timeanddate.com,
    321     by adding five time zone changes since 2020.  Casey is now at +08
    322     instead of +11.
    323 
    324   Changes to past tm_isdst flags
    325 
    326     Much of Greenland, represented by America/Nuuk, changed its
    327     standard time from -03 to -02 on 2023-03-25, not on 2023-10-28.
    328     This does not affect UTC offsets, only the tm_isdst flag.
    329     (Thanks to Thomas M. Steenholdt.)
    330 
    331   New data file
    332 
    333     A new data file zonenow.tab helps configure applications that use
    334     timestamps dated from now on.  This simplifies configuration,
    335     since users choose from a smaller Zone set.  The file's format is
    336     experimental and subject to change.
    337 
    338   Changes to code
    339 
    340     localtime.c no longer mishandles TZif files that contain a single
    341     transition into a DST regime.  Previously, it incorrectly assumed
    342     DST was in effect before the transition too.  (Thanks to Alois
    343     Treindl for debugging help.)
    344 
    345     localtime.c's timeoff no longer collides with OpenBSD 7.4.
    346 
    347     The C code now uses _Generic only if __STDC_VERSION__ says the
    348     compiler is C11 or later.
    349 
    350     tzselect now optionally reads zonenow.tab, to simplify when
    351     configuring only for timestamps dated from now on.
    352 
    353     tzselect no longer creates temporary files.
    354 
    355     tzselect no longer mishandles the following:
    356 
    357       Spaces and most other special characters in BUGEMAIL, PACKAGE,
    358       TZDIR, and VERSION.
    359 
    360       TZ strings when using mawk 1.4.3, which mishandles regular
    361       expressions of the form /X{2,}/.
    362 
    363       ISO 6709 coordinates when using an awk that lacks the GNU
    364       extension of newlines in -v option-arguments.
    365 
    366       Non UTF-8 locales when using an iconv command that lacks the GNU
    367       //TRANSLIT extension.
    368 
    369     zic no longer mishandles data for Palestine after the year 2075.
    370     Previously, it incorrectly omitted post-2075 transitions that are
    371     predicted for just before and just after Ramadan.  (Thanks to Ken
    372     Murchison for debugging help.)
    373 
    374     zic now works again on Linux 2.6.16 and 2.6.17 (2006).
    375     (Problem reported by Rune Torgersen.)
    376 
    377   Changes to build procedure
    378 
    379     The Makefile is now more compatible with POSIX:
    380      * It no longer defines AR, CC, CFLAGS, LDFLAGS, and SHELL.
    381      * It no longer uses its own 'cc' in place of CC.
    382      * It now uses ARFLAGS, with default specified by POSIX.
    383      * It does not use LFLAGS incompatibly with POSIX.
    384      * It uses the special .POSIX target.
    385      * It quotes special characters more carefully.
    386      * It no longer mishandles builds in an ISO 8859 locale.
    387     Due to the CC changes, TZDIR is now #defined in a file tzdir.h
    388     built by 'make', not in a $(CC) -D option.  Also, TZDEFAULT is
    389     now treated like TZDIR as they have similar roles.
    390 
    391   Changes to commentary
    392 
    393      Limitations and hazards of the optional support for obsolescent
    394      C89 platforms are documented better, along with a tentative
    395      schedule for removing this support.
    396 
    397 
    398 Release 2023c - 2023-03-28 12:42:14 -0700
    399 
    400   Changes to past and future timestamps
    401 
    402     Model Lebanon's DST chaos by reverting data to tzdb 2023a.
    403     (Thanks to Rany Hany for the heads-up.)
    404 
    405 
    406 Release 2023b - 2023-03-23 19:50:38 -0700
    407 
    408   Changes to future timestamps
    409 
    410     This year Lebanon springs forward April 20/21 not March 25/26.
    411     (Thanks to Saadallah Itani.)  [This was reverted in 2023c.]
    412 
    413 
    414 Release 2023a - 2023-03-22 12:39:33 -0700
    415 
    416   Briefly:
    417     Egypt now uses DST again, from April through October.
    418     This year Morocco springs forward April 23, not April 30.
    419     Palestine delays the start of DST this year.
    420     Much of Greenland still uses DST from 2024 on.
    421     America/Yellowknife now links to America/Edmonton.
    422     tzselect can now use current time to help infer timezone.
    423     The code now defaults to C99 or later.
    424     Fix use of C23 attributes.
    425 
    426   Changes to future timestamps
    427 
    428     Starting in 2023, Egypt will observe DST from April's last Friday
    429     through October's last Thursday.  (Thanks to Ahmad ElDardiry.)
    430     Assume the transition times are 00:00 and 24:00, respectively.
    431 
    432     In 2023 Morocco's spring-forward transition after Ramadan
    433     will occur April 23, not April 30.  (Thanks to Milamber.)
    434     Adjust predictions for future years accordingly.  This affects
    435     predictions for 2023, 2031, 2038, and later years.
    436 
    437     This year Palestine will delay its spring forward from
    438     March 25 to April 29 due to Ramadan.  (Thanks to Heba Hamad.)
    439     Make guesses for future Ramadans too.
    440 
    441     Much of Greenland, represented by America/Nuuk, will continue to
    442     observe DST using European Union rules.  When combined with
    443     Greenland's decision not to change the clocks in fall 2023,
    444     America/Nuuk therefore changes from -03/-02 to -02/-01 effective
    445     2023-10-29 at 01:00 UTC.  (Thanks to Thomas M. Steenholdt.)
    446     This change from 2022g doesn't affect timestamps until 2024-03-30,
    447     and doesn't affect tm_isdst until 2023-03-25.
    448 
    449   Changes to past timestamps
    450 
    451     America/Yellowknife has changed from a Zone to a backward
    452     compatibility Link, as it no longer differs from America/Edmonton
    453     since 1970.  (Thanks to Almaz Mingaleev.)  This affects some
    454     pre-1948 timestamps.  The old data are now in 'backzone'.
    455 
    456   Changes to past time zone abbreviations
    457 
    458     When observing Moscow time, Europe/Kirov and Europe/Volgograd now
    459     use the abbreviations MSK/MSD instead of numeric abbreviations,
    460     for consistency with other timezones observing Moscow time.
    461 
    462   Changes to code
    463 
    464     You can now tell tzselect local time, to simplify later choices.
    465     Select the 'time' option in its first prompt.
    466 
    467     You can now compile with -DTZNAME_MAXIMUM=N to limit time zone
    468     abbreviations to N bytes (default 255).  The reference runtime
    469     library now rejects POSIX-style TZ strings that contain longer
    470     abbreviations, treating them as UTC.  Previously the limit was
    471     platform dependent and abbreviations were silently truncated to
    472     16 bytes even when the limit was greater than 16.
    473 
    474     The code by default is now designed for C99 or later.  To build on
    475     a mostly-C89 platform, compile with -DPORT_TO_C89; this should
    476     work on C89 platforms that also support C99 'long long' and
    477     perhaps a few other extensions to C89.  To support C89 callers of
    478     tzcode's library, compile with -DSUPPORT_C89; however, this could
    479     trigger latent bugs in C99-or-later callers.  The two new macros
    480     are transitional aids planned to be removed in a future version
    481     (say, in 2029), when C99 or later will be required.
    482 
    483     The code now builds again on pre-C99 platforms, if you compile
    484     with -DPORT_TO_C89.  This fixes a bug introduced in 2022f.
    485 
    486     On C23-compatible platforms tzcode no longer uses syntax like
    487     'static [[noreturn]] void usage(void);'.  Instead, it uses
    488     '[[noreturn]] static void usage(void);' as strict C23 requires.
    489     (Problem reported by Houge Langley.)
    490 
    491     The code's functions now constrain their arguments with the C
    492     'restrict' keyword consistently with their documentation.
    493     This may allow future optimizations.
    494 
    495     zdump again builds standalone with ckdadd and without setenv,
    496     fixing a bug introduced in 2022g.  (Problem reported by panic.)
    497 
    498     leapseconds.awk can now process a leap seconds file that never
    499     expires; this might be useful if leap seconds are discontinued.
    500 
    501   Changes to commentary
    502 
    503     tz-link.html has a new section "Coordinating with governments and
    504     distributors".  (Thanks to Neil Fuller for some of the text.)
    505 
    506     To improve tzselect diagnostics, zone1970.tab's comments column is
    507     now limited to countries that have multiple timezones.
    508 
    509     Note that there are plans to discontinue leap seconds by 2035.
    510 
    511 
    512 Release 2022g - 2022-11-29 08:58:31 -0800
    513 
    514   Briefly:
    515     The northern edge of Chihuahua changes to US timekeeping.
    516     Much of Greenland stops changing clocks after March 2023.
    517     Fix some pre-1996 timestamps in northern Canada.
    518     C89 is now deprecated; please use C99 or later.
    519     Portability fixes for AIX, libintl, MS-Windows, musl, z/OS
    520     In C code, use more C23 features if available.
    521     C23 timegm now supported by default
    522     Fixes for unlikely integer overflows
    523 
    524   Changes to future timestamps
    525 
    526     In the Mexican state of Chihuahua, the border strip near the US
    527     will change to agree with nearby US locations on 2022-11-30.
    528     The strip's western part, represented by Ciudad Jurez, switches
    529     from -06 all year to -07/-06 with US DST rules, like El Paso, TX.
    530     The eastern part, represented by Ojinaga, will observe US DST next
    531     year, like Presidio, TX.  (Thanks to Heitor David Pinto.)
    532     A new Zone America/Ciudad_Juarez splits from America/Ojinaga.
    533 
    534     Much of Greenland, represented by America/Nuuk, stops observing
    535     winter time after March 2023, so its daylight saving time becomes
    536     standard time.  (Thanks to Jonas Nyrup and Jrgen Appel.)
    537 
    538   Changes to past timestamps
    539 
    540     Changes for pre-1996 northern Canada (thanks to Chris Walton):
    541 
    542       Merge America/Iqaluit and America/Pangnirtung into the former,
    543       with a backward compatibility link for the latter name.
    544       There is no good evidence the two locations differ since 1970.
    545       This change affects pre-1996 America/Pangnirtung timestamps.
    546 
    547       Cambridge Bay, Inuvik, Iqaluit, Rankin Inlet, Resolute and
    548       Yellowknife did not observe DST in 1965, and did observe DST
    549       from 1972 through 1979.
    550 
    551       Whitehorse moved from -09 to -08 on 1966-02-27, not 1967-05-28.
    552 
    553     Colombia's 1993 fallback was 02-06 24:00, not 04-04 00:00.
    554     (Thanks to Alois Treindl.)
    555 
    556     Singapore's 1981-12-31 change was at 16:00 UTC (23:30 local time),
    557     not 24:00 local time.  (Thanks to Geoff Clare via Robert Elz.)
    558 
    559   Changes to code
    560 
    561     Although tzcode still works with C89, bugs found in recent routine
    562     maintenance indicate that bitrot has set in and that in practice
    563     C89 is no longer used to build tzcode.  As it is a maintenance
    564     burden, support for C89 is planned to be removed soon.  Instead,
    565     please use compilers compatible with C99, C11, C17, or C23.
    566 
    567     timegm, which tzcode implemented in 1989, will finally be
    568     standardized 34 years later as part of C23, so timegm is now
    569     supported even if STD_INSPIRED is not defined.
    570 
    571     Fix bug in zdump's tzalloc emulation on hosts that lack tm_zone.
    572     (Problem reported by on Trn Cng Danh.)
    573 
    574     Fix bug in zic on hosts where malloc(0) yields NULL on success.
    575     (Problem reported by Tim McBrayer for AIX 6.1.)
    576 
    577     Fix zic configuration to avoid linkage failures on some platforms.
    578     (Problems reported by Gilmore Davidson and Igor Ivanov.)
    579 
    580     Work around MS-Windows nmake incompatibility with POSIX.
    581     (Problem reported by Manuela Friedrich.)
    582 
    583     Port mktime and strftime to debugging platforms where accessing
    584     uninitialized data has undefined behavior (strftime problem
    585     reported by Robert Elz).
    586 
    587     Check more carefully for unlikely integer overflows, preferring
    588     C23 <stdckdint.h> to overflow checking by hand, as the latter has
    589     had obscure bugs.
    590 
    591   Changes to build procedure
    592 
    593     New Makefile rule check_mild that skips checking whether Link
    594     lines are in the file 'backward'.  (Inspired by a suggestion from
    595     Stephen Colebourne.)
    596 
    597     On C23-compatible platforms tzcode no longer uses syntax like
    598     'static [[noreturn]] void usage(void);'.  Instead, it uses
    599     '[[noreturn]] static void usage(void);' as strict C23 requires.
    600     (Problem reported by Houge Langley.)
    601 
    602 
    603 Release 2022f - 2022-10-28 18:04:57 -0700
    604 
    605   Briefly:
    606     Mexico will no longer observe DST except near the US border.
    607     Chihuahua moves to year-round -06 on 2022-10-30.
    608     Fiji no longer observes DST.
    609     Move links to 'backward'.
    610     In vanguard form, GMT is now a Zone and Etc/GMT a link.
    611     zic now supports links to links, and vanguard form uses this.
    612     Simplify four Ontario zones.
    613     Fix a Y2438 bug when reading TZif data.
    614     Enable 64-bit time_t on 32-bit glibc platforms.
    615     Omit large-file support when no longer needed.
    616     In C code, use some C23 features if available.
    617     Remove no-longer-needed workaround for Qt bug 53071.
    618 
    619   Changes to future timestamps
    620 
    621     Mexico will no longer observe DST after 2022, except for areas
    622     near the US border that continue to observe US DST rules.
    623     On 2022-10-30 at 02:00 the Mexican state of Chihuahua moves
    624     from -07 (-06 with DST) to year-round -06, thus not changing
    625     its clocks that day.  The new law states that Chihuahua
    626     near the US border no longer observes US DST.
    627     (Thanks to gera for the heads-up about Chihuahua.)
    628 
    629     Fiji will not observe DST in 2022/3.  (Thanks to Shalvin Narayan.)
    630     For now, assume DST is suspended indefinitely.
    631 
    632   Changes to data
    633 
    634     Move links to 'backward' to ease and simplify link maintenance.
    635     This affects generated data only if you use 'make BACKWARD='.
    636 
    637     GMT is now a Zone and Etc/GMT a link instead of vice versa,
    638     as GMT is needed for leap second support whereas Etc/GMT is not.
    639     However, this change exposes a bug in TZUpdater 2.3.2 so it is
    640     present only in vanguard form for now.
    641 
    642     Vanguard form now uses links to links, as zic now supports this.
    643 
    644   Changes to past timestamps
    645 
    646     Simplify four Ontario zones, as most of the post-1970 differences
    647     seem to have been imaginary.  (Problem reported by Chris Walton.)
    648     Move America/Nipigon, America/Rainy_River, and America/Thunder_Bay
    649     to 'backzone'; backward-compatibility links still work, albeit
    650     with some different timestamps before November 2005.
    651 
    652   Changes to code
    653 
    654     zic now supports links to links regardless of input line order.
    655     For example, if Australia/Sydney is a Zone, the lines
    656       Link Australia/Canberra Australia/ACT
    657       Link Australia/Sydney Australia/Canberra
    658     now work correctly, even though the shell commands
    659       ln Australia/Canberra Australia/ACT
    660       ln Australia/Sydney Australia/Canberra
    661     would fail because the first command attempts to use a link
    662     Australia/Canberra that does not exist until after the second
    663     command is executed.  Previously, zic had unspecified behavior if
    664     a Link line's target was another link, and zic often misbehaved if
    665     a Link line's target was a later Link line.
    666 
    667     Fix line number in zic's diagnostic for a link to a link.
    668 
    669     Fix a bug that caused localtime to mishandle timestamps starting
    670     in the year 2438 when reading data generated by 'zic -b fat' when
    671     distant-future DST transitions occur at times given in standard
    672     time or in UT, not the usual case of local time.  This occurs when
    673     the corresponding .zi Rule lines specify DST transitions with TO
    674     columns of 'max' and AT columns that end in 's' or 'u'.  The
    675     number 2438 comes from the 32-bit limit in the year 2038, plus the
    676     400-year Gregorian cycle.  (Problem reported by Bradley White.)
    677 
    678     On glibc 2.34 and later, which optionally supports 64-bit time_t
    679     on platforms like x86 where time_t was traditionally 32 bits,
    680     default time_t to 64 instead of 32 bits.  This lets functions like
    681     localtime support timestamps after the year 2038, and fixes
    682     year-2038 problems in zic when accessing files dated after 2038.
    683     To continue to limit time_t to 32 bits on these platforms, use
    684     "make CFLAGS='-D_TIME_BITS=32'".
    685 
    686     In C code, do not enable large-file support on platforms like AIX
    687     and macOS that no longer need it now that tzcode does not use
    688     off_t or related functions like 'stat'.  Large-file support is
    689     still enabled by default on GNU/Linux, as it is needed for 64-bit
    690     time_t support.
    691 
    692     In C code, prefer C23 keywords to pre-C23 macros for alignof,
    693     bool, false, and true.  Also, use the following C23 features if
    694     available: __has_include, unreachable.
    695 
    696     zic no longer works around Qt bug 53071, as the relevant Qt
    697     releases have been out of support since 2019.  This change affects
    698     only fat TZif files, as thin files never had the workaround.
    699 
    700     zdump no longer modifies the environ vector when compiled on
    701     platforms lacking tm_zone or when compiled with -DUSE_LTZ=0.
    702     This avoid undefined behavior on POSIX platforms.
    703 
    704 
    705 Release 2022e - 2022-10-11 11:13:02 -0700
    706 
    707   Briefly:
    708     Jordan and Syria switch from +02/+03 with DST to year-round +03.
    709 
    710   Changes to future timestamps
    711 
    712     Jordan and Syria are abandoning the DST regime and are changing to
    713     permanent +03, so they will not fall back from +03 to +02 on
    714     2022-10-28.  (Thanks to Steffen Thorsen and Issam Al-Zuwairi.)
    715 
    716   Changes to past timestamps
    717 
    718     On 1922-01-01 Tijuana adopted standard time at 00:00, not 01:00.
    719 
    720   Changes to past time zone abbreviations and DST flags
    721 
    722     The temporary advancement of clocks in central Mexico in summer
    723     1931 is now treated as daylight saving time, instead of as two
    724     changes to standard time.
    725 
    726 
    727 Release 2022d - 2022-09-23 12:02:57 -0700
    728 
    729   Briefly:
    730     Palestine transitions are now Saturdays at 02:00.
    731     Simplify three Ukraine zones into one.
    732 
    733   Changes to future timestamps
    734 
    735     Palestine now springs forward and falls back at 02:00 on the
    736     first Saturday on or after March 24 and October 24, respectively.
    737     This means 2022 falls back 10-29 at 02:00, not 10-28 at 01:00.
    738     (Thanks to Heba Hamad.)
    739 
    740   Changes to past timestamps
    741 
    742     Simplify three Ukraine zones to one, since the post-1970
    743     differences seem to have been imaginary.  Move Europe/Uzhgorod and
    744     Europe/Zaporozhye to 'backzone'; backward-compatibility links
    745     still work, albeit with different timestamps before October 1991.
    746 
    747 
    748 Release 2022c - 2022-08-15 17:47:18 -0700
    749 
    750   Briefly:
    751     Work around awk bug in FreeBSD, macOS, etc.
    752     Improve tzselect on intercontinental Zones.
    753 
    754   Changes to code
    755 
    756     Work around a bug in onetrueawk that broke commands like
    757     'make traditional_tarballs' on FreeBSD, macOS, etc.
    758     (Problem reported by Deborah Goldsmith.)
    759 
    760     Add code to tzselect that uses experimental structured comments in
    761     zone1970.tab to clarify whether Zones like Africa/Abidjan and
    762     Europe/Istanbul cross continent or ocean boundaries.
    763     (Inspired by a problem reported by Peter Krefting.)
    764 
    765     Fix bug with 'zic -d /a/b/c' when /a is unwritable but the
    766     directory /a/b already exists.
    767 
    768     Remove zoneinfo2tdf.pl, as it was unused and triggered false
    769     malware alarms on some email servers.
    770 
    771 
    772 Release 2022b - 2022-08-10 15:38:32 -0700
    773 
    774   Briefly:
    775     Chile's DST is delayed by a week in September 2022.
    776     Iran no longer observes DST after 2022.
    777     Rename Europe/Kiev to Europe/Kyiv.
    778     New zic -R option
    779     Vanguard form now uses %z.
    780     Finish moving duplicate-since-1970 zones to 'backzone'.
    781     New build option PACKRATLIST
    782     New tailored_tarballs target, replacing rearguard_tarballs
    783 
    784   Changes to future timestamps
    785 
    786     Chile's 2022 DST start is delayed from September 4 to September 11.
    787     (Thanks to Juan Correa.)
    788 
    789     Iran plans to stop observing DST permanently, after it falls back
    790     on 2022-09-21.  (Thanks to Ali Mirjamali.)
    791 
    792   Changes to past timestamps
    793 
    794     Finish moving to 'backzone' the location-based zones whose
    795     timestamps since 1970 are duplicates; adjust links accordingly.
    796     This change ordinarily affects only pre-1970 timestamps, and with
    797     the new PACKRATLIST option it does not affect any timestamps.
    798     In this round the affected zones are Antarctica/Vostok,
    799     Asia/Brunei, Asia/Kuala_Lumpur, Atlantic/Reykjavik,
    800     Europe/Amsterdam, Europe/Copenhagen, Europe/Luxembourg,
    801     Europe/Monaco, Europe/Oslo, Europe/Stockholm, Indian/Christmas,
    802     Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Reunion,
    803     Pacific/Chuuk, Pacific/Funafuti, Pacific/Majuro, Pacific/Pohnpei,
    804     Pacific/Wake and Pacific/Wallis, and the affected links are
    805     Arctic/Longyearbyen, Atlantic/Jan_Mayen, Iceland, Pacific/Ponape,
    806     Pacific/Truk, and Pacific/Yap.
    807 
    808     From fall 1994 through fall 1995, Shanks wrote that Crimea's
    809     DST transitions were at 02:00 standard time, not at 00:00.
    810     (Thanks to Michael Deckers.)
    811 
    812     Iran adopted standard time in 1935, not 1946.  In 1977 it observed
    813     DST from 03-21 23:00 to 10-20 24:00; its 1978 transitions were on
    814     03-24 and 08-05, not 03-20 and 10-20; and its spring 1979
    815     transition was on 05-27, not 03-21.
    816     (Thanks to Roozbeh Pournader and Francis Santoni.)
    817 
    818     Chile's observance of -04 from 1946-08-29 through 1947-03-31 was
    819     considered DST, not standard time.  Santiago and environs had moved
    820     their clocks back to rejoin the rest of mainland Chile; put this
    821     change at the end of 1946-08-28.  (Thanks to Michael Deckers.)
    822 
    823     Some old, small clock transitions have been removed, as people at
    824     the time did not change their clocks.  This affects Asia/Hong_Kong
    825     in 1904, Asia/Ho_Chi_Minh in 1906, and Europe/Dublin in 1880.
    826 
    827   Changes to zone name
    828 
    829     Rename Europe/Kiev to Europe/Kyiv, as "Kyiv" is more common in
    830     English now.  Spelling of other names in Ukraine has not yet
    831     demonstrably changed in common English practice so for now these
    832     names retain old spellings, as in other countries (e.g.,
    833     Europe/Prague not "Praha", and Europe/Sofia not "Sofiya").
    834 
    835   Changes to code
    836 
    837     zic has a new option '-R @N' to output explicit transitions < N.
    838     (Need suggested by Almaz Mingaleev.)
    839 
    840     'zic -r @N' no longer outputs bad data when N < first transition.
    841     (Problem introduced in 2021d and reported by Peter Krefting.)
    842 
    843     zic now checks its input for NUL bytes and unterminated lines, and
    844     now supports input line lengths up to 2048 (not 512) bytes.
    845 
    846     gmtime and related code now use the abbreviation "UTC" not "GMT".
    847     POSIX is being revised to require this.
    848 
    849     When tzset and related functions set vestigial static variables
    850     like tzname, they now prefer specified timestamps to unspecified ones.
    851     (Problem reported by Almaz Mingaleev.)
    852 
    853     zic no longer complains "can't determine time zone abbreviation to
    854     use just after until time" when a transition to a new standard
    855     time occurs simultaneously with the first DST fallback transition.
    856 
    857   Changes to build procedure
    858 
    859     Source data in vanguard form now uses the %z notation, introduced
    860     in release 2015f.  For example, for America/Sao_Paulo vanguard
    861     form contains the zone continuation line "-3:00 Brazil %z", which
    862     is simpler and more reliable than the line "-3:00 Brazil -03/-02"
    863     used in main and rearguard forms.  The plan is for the main form
    864     to use %z eventually; in the meantime maintainers of zi parsers
    865     are encouraged to test the parsers on vanguard.zi.
    866 
    867     The Makefile has a new PACKRATLIST option to select a subset of
    868     'backzone'.  For example, 'make PACKRATDATA=backzone
    869     PACKRATLIST=zone.tab' now generates TZif files identical to those
    870     of the global-tz project.
    871 
    872     The Makefile has a new tailored_tarballs target for generating
    873     special-purpose tarballs.  It generalizes and replaces the
    874     rearguard_tarballs target and related targets and macros, which
    875     are now obsolescent.
    876 
    877     'make install' now defaults LOCALTIME to Factory not GMT,
    878     which means the default abbreviation is now "-00" not "GMT".
    879 
    880     Remove the posix_packrat target, marked obsolescent in 2016a.
    881 
    882 
    883 Release 2022a - 2022-03-15 23:02:01 -0700
    884 
    885   Briefly:
    886     Palestine will spring forward on 2022-03-27, not -03-26.
    887     zdump -v now outputs better failure indications.
    888     Bug fixes for code that reads corrupted TZif data.
    889 
    890   Changes to future timestamps
    891 
    892     Palestine will spring forward on 2022-03-27, not 2022-03-26.
    893     (Thanks to Heba Hamad.)  Predict future transitions for first
    894     Sunday >= March 25.  Additionally, predict fallbacks to be the first
    895     Friday on or after October 23, not October's last Friday, to be more
    896     consistent with recent practice.  The first differing fallback
    897     prediction is on 2025-10-24, not 2025-10-31.
    898 
    899   Changes to past timestamps
    900 
    901     From 1992 through spring 1996, Ukraine's DST transitions were at
    902     02:00 standard time, not at 01:00 UTC.  (Thanks to Alois Treindl.)
    903 
    904     Chile's Santiago Mean Time and its LMT precursor have been adjusted
    905     eastward by 1 second to align with past and present law.
    906 
    907   Changes to commentary
    908 
    909     Add several references for Chile's 1946/1947 transitions, some of
    910     which only affected portions of the country.
    911 
    912   Changes to code
    913 
    914     Fix bug when mktime gets confused by truncated TZif files with
    915     unspecified local time.  (Problem reported by Almaz Mingaleev.)
    916 
    917     Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
    918     (Problem reported by Christos Zoulas.)
    919 
    920     When reading a version 2 or later TZif file, the TZif reader now
    921     validates the version 1 header and data block only enough to skip
    922     over them, as recommended by RFC 8536 section 4.  Also, the TZif
    923     reader no longer mistakenly attempts to parse a version 1 TZIf
    924     file header as a TZ string.
    925 
    926     zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
    927     when local time and UT cannot be determined for a timestamp.
    928 
    929   Changes to build procedure
    930 
    931     Distribution tarballs now use standard POSIX.1-1988 ustar format
    932     instead of GNU format.  Although the formats are almost identical
    933     for these tarballs, ustar headers' magic fields contain "ustar"
    934     instead of "ustar ", and their version fields contain "00" instead
    935     of " ".  The two formats are planned to diverge more significantly
    936     for tzdb releases after 2242-03-16 12:56:31 UTC, when the ustar
    937     format becomes obsolete and the tarballs switch to pax format, an
    938     extension of ustar.  For details about these formats, please see
    939     "pax - portable archive interchange", IEEE Std 1003.1-2017,
    940     <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13>.
    941 
    942 
    943 Release 2021e - 2021-10-21 18:41:00 -0700
    944 
    945   Changes to future timestamps
    946 
    947     Palestine will fall back 10-29 (not 10-30) at 01:00.
    948     (Thanks to P Chan and Heba Hemad.)
    949 
    950 
    951 Release 2021d - 2021-10-15 13:48:18 -0700
    952 
    953   Briefly:
    954     Fiji suspends DST for the 2021/2022 season.
    955     'zic -r' marks unspecified timestamps with "-00".
    956 
    957   Changes to future timestamps
    958 
    959     Fiji will suspend observance of DST for the 2021/2022 season.
    960     Assume for now that it will return next year.  (Thanks to Jashneel
    961     Kumar and P Chan.)
    962 
    963   Changes to code
    964 
    965     'zic -r' now uses "-00" time zone abbreviations for intervals
    966     with UT offsets that are unspecified due to -r truncation.
    967     This implements a change in draft Internet RFC 8536bis.
    968 
    969 
    970 Release 2021c - 2021-10-01 14:21:49 -0700
    971 
    972   Briefly:
    973     Revert most 2021b changes to 'backward'.
    974     Fix 'zic -b fat' bug in pre-1970 32-bit data.
    975     Fix two Link line typos.
    976     Distribute SECURITY file.
    977 
    978     This release is intended as a bugfix release, to fix compatibility
    979     problems and typos reported since 2021b was released.
    980 
    981   Changes to Link directives
    982 
    983     Revert almost all of 2021b's changes to the 'backward' file,
    984     by moving Link directives back to where they were in 2021a.
    985     Although 'zic' doesn't care which source file contains a Link
    986     directive, some downstream uses ran into trouble with the move.
    987     (Problem reported by Stephen Colebourne for Joda-Time.)
    988 
    989     Fix typo that linked Atlantic/Jan_Mayen to the wrong location
    990     (problem reported by Chris Walton).
    991 
    992     Fix 'backzone' typo that linked America/Virgin to the wrong
    993     location (problem reported by Michael Deckers).
    994 
    995   Changes to code
    996 
    997     Fix a bug in 'zic -b fat' that caused old timestamps to be
    998     mishandled in 32-bit-only readers (problem reported by Daniel
    999     Fischer).
   1000 
   1001   Changes to documentation
   1002 
   1003     Distribute the SECURITY file (problem reported by Andreas Radke).
   1004 
   1005 
   1006 Release 2021b - 2021-09-24 16:23:00 -0700
   1007 
   1008   Briefly:
   1009     Jordan now starts DST on February's last Thursday.
   1010     Samoa no longer observes DST.
   1011     Merge more location-based Zones whose timestamps agree since 1970.
   1012     Move some backward-compatibility links to 'backward'.
   1013     Rename Pacific/Enderbury to Pacific/Kanton.
   1014     Correct many pre-1993 transitions in Malawi, Portugal, etc.
   1015     zic now creates each output file or link atomically.
   1016     zic -L no longer omits the POSIX TZ string in its output.
   1017     zic fixes for truncation and leap second table expiration.
   1018     zic now follows POSIX for TZ strings using all-year DST.
   1019     Fix some localtime crashes and bugs in obscure cases.
   1020     zdump -v now outputs more-useful boundary cases.
   1021     tzfile.5 better matches a draft successor to RFC 8536.
   1022     A new file SECURITY.
   1023 
   1024     This release is prompted by recent announcements by Jordan and Samoa.
   1025     It incorporates many other changes that had accumulated since 2021a.
   1026     However, it omits most proposed changes that merged all Zones
   1027     agreeing since 1970, as concerns were raised about doing too many of
   1028     these changes at once.  It does keeps some of these changes in the
   1029     interest of making tzdb more equitable one step at a time; see
   1030     "Merge more location-based Zones" below.
   1031 
   1032   Changes to future timestamps
   1033 
   1034     Jordan now starts DST on February's last Thursday.
   1035     (Thanks to Steffen Thorsen.)
   1036 
   1037     Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
   1038 
   1039   Changes to zone name
   1040 
   1041     Rename Pacific/Enderbury to Pacific/Kanton.  When we added
   1042     Enderbury in 1993, we did not know that it is uninhabited and that
   1043     Kanton (population two dozen) is the only inhabited location in
   1044     that timezone.  The old name is now a backward-compatibility link.
   1045 
   1046   Changes to past timestamps
   1047 
   1048     Correct many pre-1993 transitions, fixing entries originally
   1049     derived from Shanks, Whitman, and Mundell.  The fixes include:
   1050       - Barbados: standard time was introduced in 1911, not 1932; and
   1051 	DST was observed in 1942-1944
   1052       - Cook Islands: In 1899 they switched from east to west of GMT,
   1053 	celebrating Christmas for two days.  They (and Niue) switched
   1054 	to standard time in 1952, not 1901.
   1055       - Guyana: corrected LMT for Georgetown; the introduction of
   1056 	standard time in 1911, not 1915; and corrections to 1975 and
   1057 	1992 transitions
   1058       - Kanton: uninhabited before 1937-08-31
   1059       - Niue: only observed -11:20 from 1952 through 1964, then went to
   1060         -11 instead of -11:30
   1061       - Portugal: DST was observed in 1950
   1062       - Tonga: corrected LMT; the introduction of standard time in 1945,
   1063         not 1901; and corrections to the transition from +12:20 to +13
   1064         in 1961, not 1941
   1065     Additional fixes to entries in the 'backzone' file include:
   1066       - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
   1067       - The Gambia: 1933 and 1942 transitions
   1068       - Malawi: several 1911 through 1925 transitions
   1069       - Sierra Leone: several 1913 through 1941 transitions, and DST
   1070 	was NOT observed in 1957 through 1962
   1071     (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
   1072     Alois Treindl.)
   1073 
   1074     Merge more location-based Zones whose timestamps agree since 1970,
   1075     as pre-1970 timestamps are out of scope.  This is part of a
   1076     process that has been ongoing since 2013.  This does not affect
   1077     post-1970 timestamps, and timezone historians who build with 'make
   1078     PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
   1079     When merging, keep the most-populous location's data, and move
   1080     data for other locations to 'backzone' with a backward
   1081     link in 'backward'.  For example, move America/Creston data to
   1082     'backzone' with a link in 'backward' from America/Phoenix because
   1083     the two timezones' timestamps agree since 1970; this change
   1084     affects some pre-1968 timestamps in America/Creston because
   1085     Creston and Phoenix disagreed before 1968.  The affected Zones
   1086     are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
   1087     America/Creston, America/Curacao, America/Nassau,
   1088     America/Port_of_Spain, Antarctica/DumontDUrville, and
   1089     Antarctica/Syowa.
   1090 
   1091   Changes to maintenance procedure
   1092 
   1093     The new file SECURITY covers how to report security-related bugs.
   1094 
   1095     Several backward-compatibility links have been moved to the
   1096     'backward' file.  These links, which range from Africa/Addis_Ababa
   1097     to Pacific/Saipan, are only for compatibility with now-obsolete
   1098     guidelines suggesting an entry for every ISO 3166 code.
   1099     The intercontinental convenience links Asia/Istanbul and
   1100     Europe/Nicosia have also been moved to 'backward'.
   1101 
   1102   Changes to code
   1103 
   1104     zic now creates each output file or link atomically,
   1105     possibly by creating a temporary file and then renaming it.
   1106     This avoids races where a TZ setting would temporarily stop
   1107     working while zic was installing a replacement file or link.
   1108 
   1109     zic -L no longer omits the POSIX TZ string in its output.
   1110     Starting with 2020a, zic -L truncated its output according to the
   1111     "Expires" directive or "#expires" comment in the leapseconds file.
   1112     The resulting TZif files omitted daylight saving transitions after
   1113     the leap second table expired, which led to far less accurate
   1114     predictions of times after the expiry.  Although future timestamps
   1115     cannot be converted accurately in the presence of leap seconds, it
   1116     is more accurate to convert near-future timestamps with a few
   1117     seconds error than with an hour error, so zic -L no longer
   1118     truncates output in this way.
   1119 
   1120     Instead, when zic -L is given the "Expires" directive, it now
   1121     outputs the expiration by appending a no-change entry to the leap
   1122     second table.  Although this should work well with most TZif
   1123     readers, it does not conform to Internet RFC 8536 and some pickier
   1124     clients (including tzdb 2017c through 2021a) reject it, so
   1125     "Expires" directives are currently disabled by default.  To enable
   1126     them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
   1127     this new feature it is marked with a new TZif version number 4,
   1128     a format intended to be documented in a successor to RFC 8536.
   1129     The old-format "#expires" comments are now treated solely as
   1130     comments and have no effect on the TZif files.
   1131 
   1132     zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
   1133     that omits leap second information for the range LO..B when LO
   1134     falls between two leap seconds A and B.  Instead, it generates a
   1135     TZif version 4 file that represents the previously missing
   1136     information.
   1137 
   1138     The TZif reader now allows the leap second table to begin with a
   1139     correction other than -1 or +1, and to contain adjacent
   1140     transitions with equal corrections.  This supports TZif version 4.
   1141 
   1142     The TZif reader now lets leap seconds occur less than 28 days
   1143     apart.  This supports possible future TZif extensions.
   1144 
   1145     Fix bug that caused 'localtime' etc. to crash when TZ was
   1146     set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
   1147     not conform to POSIX but does conform to Internet RFC 8536.
   1148 
   1149     Fix another bug that caused 'localtime' etc. to crash when TZ was
   1150     set to a POSIX-conforming but unusual TZ string like
   1151     "EST5EDT4,0/0,J365/0", where almost all the year is DST.
   1152 
   1153     Fix yet another bug that caused 'localtime' etc. to mishandle slim
   1154     TZif files containing leap seconds after the last explicit
   1155     transition in the table, or when handling far-future timestamps
   1156     in slim TZif files lacking leap seconds.
   1157 
   1158     Fix localtime misbehavior involving positive leap seconds.
   1159     This change affects only behavior for "right" system time,
   1160     which contains leap seconds, and only if the UT offset is
   1161     not a multiple of 60 seconds when a positive leap second occurs.
   1162     (No such timezone exists in tzdb, luckily.)  Without the fix,
   1163     the timestamp was ambiguous during a positive leap second.
   1164     With the fix, any seconds occurring after a positive leap second
   1165     and within the same localtime minute are counted through 60, not
   1166     through 59; their UT offset (tm_gmtoff) is the same as before.
   1167     Here is how the fix affects timestamps in a timezone with UT
   1168     offset +01:23:45 (5025 seconds) and with a positive leap second at
   1169     1972-06-30 23:59:60 UTC (78796800):
   1170 
   1171 	time_t    without the fix      with the fix
   1172 	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
   1173 	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
   1174 	...
   1175 	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
   1176 	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
   1177 
   1178     Fix an unlikely bug that caused 'localtime' etc. to misbehave if
   1179     civil time changes a few seconds before time_t wraps around, when
   1180     leap seconds are enabled.
   1181 
   1182     Fix bug in zic -r; in some cases, the dummy time type after the
   1183     last time transition disagreed with the TZ string, contrary to
   1184     Internet RFC 8563 section 3.3.
   1185 
   1186     Fix a bug with 'zic -r @X' when X is a negative leap second that
   1187     has a nonnegative correction.  Without the fix, the output file
   1188     was truncated so that X appeared to be a positive leap second.
   1189     Fix a similar, even less likely bug when truncating at a positive
   1190     leap second that has a nonpositive correction.
   1191 
   1192     zic -r now reports an error if given rolling leap seconds, as this
   1193     usage has never generally worked and is evidently unused.
   1194 
   1195     zic now generates a POSIX-conforming TZ string for TZif files
   1196     where all-year DST is predicted for the indefinite future.
   1197     For example, for all-year Eastern Daylight Time, zic now generates
   1198     "XXX3EDT4,0/0,J365/23" where it previously generated
   1199     "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
   1200     noting the possibility of POSIX conformance.)
   1201 
   1202     zic.c no longer requires sys/wait.h (thanks to spazmodius for
   1203     noting it wasn't needed).
   1204 
   1205     When reading slim TZif files, zdump no longer mishandles leap
   1206     seconds on the rare platforms where time_t counts leap seconds,
   1207     fixing a bug introduced in 2014g.
   1208 
   1209     zdump -v now outputs timestamps at boundaries of what localtime
   1210     and gmtime can represent, instead of the less useful timestamps
   1211     one day after the minimum and one day before the maximum.
   1212     (Thanks to Arthur David Olson for prototype code, and to Manuela
   1213     Friedrich for debugging help.)
   1214 
   1215     zdump's -c and -t options are now consistently inclusive for the
   1216     lower time bound and exclusive for the upper.  Formerly they were
   1217     inconsistent.  (Confusion noted by Martin Burnicki.)
   1218 
   1219   Changes to build procedure
   1220 
   1221     You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
   1222     non-POSIX hosts where malloc doesn't set errno.
   1223     (Problem reported by Jan Engelhardt.)
   1224 
   1225   Changes to documentation
   1226 
   1227     tzfile.5 better matches a draft successor to RFC 8536
   1228     <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.
   1229 
   1230 
   1231 Release 2021a - 2021-01-24 10:54:57 -0800
   1232 
   1233   Changes to future timestamps
   1234 
   1235     South Sudan changes from +03 to +02 on 2021-02-01 at 00:00.
   1236     (Thanks to Steffen Thorsen.)
   1237 
   1238 
   1239 Release 2020f - 2020-12-29 00:17:46 -0800
   1240 
   1241   Change to build procedure
   1242 
   1243     'make rearguard_tarballs' no longer generates a bad rearguard.zi,
   1244     fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
   1245 
   1246 
   1247 Release 2020e - 2020-12-22 15:14:34 -0800
   1248 
   1249   Briefly:
   1250     Volgograd switches to Moscow time on 2020-12-27 at 02:00.
   1251 
   1252   Changes to future timestamps
   1253 
   1254     Volgograd changes time zone from +04 to +03 on 2020-12-27 at 02:00.
   1255     (Thanks to Alexander Krivenyshev and Stepan Golosunov.)
   1256 
   1257   Changes to past timestamps
   1258 
   1259     Correct many pre-1986 transitions, fixing entries originally
   1260     derived from Shanks.  The fixes include:
   1261       - Australia: several 1917 through 1971 transitions
   1262       - The Bahamas: several 1941 through 1945 transitions
   1263       - Bermuda: several 1917 through 1956 transitions
   1264       - Belize: several 1942 through 1968 transitions
   1265       - Ghana: several 1915 through 1956 transitions
   1266       - Israel and Palestine: several 1940 through 1985 transitions
   1267       - Kenya and adjacent: several 1908 through 1960 transitions
   1268       - Nigeria and adjacent: correcting LMT in Lagos, and several 1905
   1269         through 1919 transitions
   1270       - Seychelles: the introduction of standard time in 1907, not 1906
   1271       - Vanuatu: DST in 1973-1974, and a corrected 1984 transition
   1272     (Thanks to P Chan.)
   1273 
   1274     Because of the Australia change, Australia/Currie (King Island) is
   1275     no longer needed, as it is identical to Australia/Hobart for all
   1276     timestamps since 1970 and was therefore created by mistake.
   1277     Australia/Currie has been moved to the 'backward' file and its
   1278     corrected data moved to the 'backzone' file.
   1279 
   1280   Changes to past time zone abbreviations and DST flags
   1281 
   1282     To better match legislation in Turks and Caicos, the 2015 shift to
   1283     year-round observance of -04 is now modeled as AST throughout before
   1284     returning to Eastern Time with US DST in 2018, rather than as
   1285     maintaining EDT until 2015-11-01.  (Thanks to P Chan.)
   1286 
   1287   Changes to documentation
   1288 
   1289     The zic man page now documents zic's coalescing of transitions
   1290     when a zone falls back just before DST springs forward.
   1291 
   1292 
   1293 Release 2020d - 2020-10-21 11:24:13 -0700
   1294 
   1295   Briefly:
   1296     Palestine ends DST earlier than predicted, on 2020-10-24.
   1297 
   1298   Changes to past and future timestamps
   1299 
   1300     Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
   1301     as previously predicted (thanks to Sharef Mustafa.)  Its
   1302     2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
   1303     Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
   1304     its spring 2020 transition was on March 28 at 00:00, not March 27
   1305     (thanks to Pierre Cashon.)  This affects Asia/Gaza and
   1306     Asia/Hebron.  Assume future spring and fall transitions will be on
   1307     the Saturday preceding the last Sunday of March and October,
   1308     respectively.
   1309 
   1310 
   1311 Release 2020c - 2020-10-16 11:15:53 -0700
   1312 
   1313   Briefly:
   1314     Fiji starts DST later than usual, on 2020-12-20.
   1315 
   1316   Changes to future timestamps
   1317 
   1318     Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
   1319     previously predicted.  DST will still end on 2021-01-17.
   1320     (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
   1321     the later-than-usual start date is a one-time departure from the
   1322     recent pattern.
   1323 
   1324   Changes to build procedure
   1325 
   1326     Rearguard tarballs now contain an empty file pacificnew.
   1327     Some older downstream software expects this file to exist.
   1328     (Problem reported by Mike Cullinan.)
   1329 
   1330 
   1331 Release 2020b - 2020-10-06 18:35:04 -0700
   1332 
   1333   Briefly:
   1334     Revised predictions for Morocco's changes starting in 2023.
   1335     Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
   1336     Macquarie Island has stayed in sync with Tasmania since 2011.
   1337     Casey, Antarctica is at +08 in winter and +11 in summer.
   1338     zic no longer supports -y, nor the TYPE field of Rules.
   1339 
   1340   Changes to future timestamps
   1341 
   1342     Morocco's spring-forward after Ramadan is now predicted to occur
   1343     no sooner than two days after Ramadan, instead of one day.
   1344     (Thanks to Milamber.)  The first altered prediction is for 2023,
   1345     now predicted to spring-forward on April 30 instead of April 23.
   1346 
   1347   Changes to past and future timestamps
   1348 
   1349    Casey Station, Antarctica has been using +08 in winter and +11 in
   1350    summer since 2018.  The most recent transition from +08 to +11 was
   1351    2020-10-04 00:01.  Also, Macquarie Island has been staying in
   1352    sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
   1353 
   1354   Changes to past and future time zone abbreviations and DST flags
   1355 
   1356     Canada's Yukon, represented by America/Whitehorse and
   1357     America/Dawson, changes its time zone rules from -08/-07 to
   1358     permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
   1359     This change affects only the time zone abbreviation (MST vs PDT)
   1360     and daylight saving flag for the period between the two dates.
   1361     (Thanks to Andrew G. Smith.)
   1362 
   1363   Changes to past timestamps
   1364 
   1365     Correct several transitions for Hungary for 1918/1983.
   1366     For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
   1367     (Thanks to Gza Nyry.)  Also, the 1890 transition to standard
   1368     time was on 11-01, not 10-01 (thanks to Michael Deckers).
   1369 
   1370     The 1891 French transition was on March 16, not March 15.  The
   1371     1911-03-11 French transition was at midnight, not a minute later.
   1372     Monaco's transitions were on 1892-06-01 and 1911-03-29, not
   1373     1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
   1374 
   1375   Changes to code
   1376 
   1377     Support for zic's long-obsolete '-y YEARISTYPE' option has been
   1378     removed and, with it, so has support for the TYPE field in Rule
   1379     lines, which is now reserved for compatibility with earlier zic.
   1380     These features were previously deprecated in release 2015f.
   1381     (Thanks to Tim Parenti.)
   1382 
   1383     zic now defaults to '-b slim' instead of to '-b fat'.
   1384 
   1385     zic's new '-l -' and '-p -' options uninstall any existing
   1386     localtime and posixrules files, respectively.
   1387 
   1388     The undocumented and ineffective tzsetwall function has been
   1389     removed.
   1390 
   1391   Changes to build procedure
   1392 
   1393     The Makefile now defaults POSIXRULES to '-', so the posixrules
   1394     feature (obsolete as of 2019b) is no longer installed by default.
   1395 
   1396   Changes to documentation and commentary
   1397 
   1398     The long-obsolete files pacificnew, systemv, and yearistype.sh have
   1399     been removed from the distribution.  (Thanks to Tim Parenti.)
   1400 
   1401 
   1402 Release 2020a - 2020-04-23 16:03:47 -0700
   1403 
   1404   Briefly:
   1405     Morocco springs forward on 2020-05-31, not 2020-05-24.
   1406     Canada's Yukon advanced to -07 year-round on 2020-03-08.
   1407     America/Nuuk renamed from America/Godthab.
   1408     zic now supports expiration dates for leap second lists.
   1409 
   1410   Changes to future timestamps
   1411 
   1412     Morocco's second spring-forward transition in 2020 will be May 31,
   1413     not May 24 as predicted earlier.  (Thanks to Semlali Naoufal.)
   1414     Adjust future-year predictions to use the first Sunday after the
   1415     day after Ramadan, not the first Sunday after Ramadan.
   1416 
   1417     Canada's Yukon, represented by America/Whitehorse and
   1418     America/Dawson, advanced to -07 year-round, beginning with its
   1419     spring-forward transition on 2020-03-08, and will not fall back on
   1420     2020-11-01.  Although a government press release calls this
   1421     "permanent Pacific Daylight Saving Time", we prefer MST for
   1422     consistency with nearby Dawson Creek, Creston, and Fort Nelson.
   1423     (Thanks to Tim Parenti.)
   1424 
   1425   Changes to past timestamps
   1426 
   1427     Shanghai observed DST in 1919.  (Thanks to Phake Nick.)
   1428 
   1429   Changes to timezone identifiers
   1430 
   1431     To reflect current usage in English better, America/Godthab has
   1432     been renamed to America/Nuuk.  A backwards-compatibility link
   1433     remains for the old name.
   1434 
   1435   Changes to code
   1436 
   1437     localtime.c no longer mishandles timestamps after the last
   1438     transition in a TZif file with leap seconds and with daylight
   1439     saving time transitions projected into the indefinite future.
   1440     For example, with TZ='America/Los_Angeles' with leap seconds,
   1441     zdump formerly reported a DST transition on 2038-03-14
   1442     from 01:59:32.999... to 02:59:33 instead of the correct transition
   1443     from 01:59:59.999... to 03:00:00.
   1444 
   1445     zic -L now supports an Expires line in the leapseconds file, and
   1446     truncates the TZif output accordingly.  This propagates leap
   1447     second expiration information into the TZif file, and avoids the
   1448     abovementioned localtime.c bug as well as similar bugs present in
   1449     many client implementations.  If no Expires line is present, zic
   1450     -L instead truncates the TZif output based on the #expires comment
   1451     present in leapseconds files distributed by tzdb 2018f and later;
   1452     however, this usage is obsolescent.  For now, the distributed
   1453     leapseconds file has an Expires line that is commented out, so
   1454     that the file can be fed to older versions of zic which ignore the
   1455     commented-out line.  Future tzdb distributions are planned to
   1456     contain a leapseconds file with an Expires line.
   1457 
   1458     The configuration macros HAVE_TZNAME and USG_COMPAT should now be
   1459     set to 1 if the system library supports the feature, and 2 if not.
   1460     As before, these macros are nonzero if tzcode should support the
   1461     feature, zero otherwise.
   1462 
   1463     The configuration macro ALTZONE now has the same values with the
   1464     same meaning as HAVE_TZNAME and USG_COMPAT.
   1465 
   1466     The code's defense against CRLF in leap-seconds.list is now
   1467     portable to POSIX awk.  (Problem reported by Deborah Goldsmith.)
   1468 
   1469     Although the undocumented tzsetwall function is not changed in
   1470     this release, it is now deprecated in preparation for removal in
   1471     future releases.  Due to POSIX requirements, tzsetwall has not
   1472     worked for some time.  Any code that uses it should instead use
   1473     tzalloc(NULL) or, if portability trumps thread-safety, should
   1474     unset the TZ environment variable.
   1475 
   1476   Changes to commentary
   1477 
   1478     The les-de-la-Madeleine and the Listuguj reserve are noted as
   1479     following America/Halifax, and comments about Yukon's "south" and
   1480     "north" have been corrected to say "east" and "west".  (Thanks to
   1481     Jeffery Nichols.)
   1482 
   1483 
   1484 Release 2019c - 2019-09-11 08:59:48 -0700
   1485 
   1486   Briefly:
   1487     Fiji observes DST from 2019-11-10 to 2020-01-12.
   1488     Norfolk Island starts observing Australian-style DST.
   1489 
   1490   Changes to future timestamps
   1491 
   1492     Fiji's next DST transitions will be 2019-11-10 and 2020-01-12
   1493     instead of 2019-11-03 and 2020-01-19.  (Thanks to Raymond Kumar.)
   1494     Adjust future guesses accordingly.
   1495 
   1496     Norfolk Island will observe Australian-style DST starting in
   1497     spring 2019.  The first transition is on 2019-10-06.  (Thanks to
   1498     Kyle Czech and Michael Deckers.)
   1499 
   1500   Changes to past timestamps
   1501 
   1502     Many corrections to time in Turkey from 1940 through 1985.
   1503     (Thanks to Oya Vula via Alois Treindl, and to Kvan Yazan.)
   1504 
   1505     The Norfolk Island 1975-03-02 transition was at 02:00 standard
   1506     time, not 02:00 DST.  (Thanks to Michael Deckers.)
   1507 
   1508     South Korea observed DST from 1948 through 1951.  Although this
   1509     info was supposed to appear in release 2014j, a typo inadvertently
   1510     suppressed the change.  (Thanks to Alois Treindl.)
   1511 
   1512     Detroit observed DST in 1967 and 1968 following the US DST rules,
   1513     except that its 1967 DST began on June 14 at 00:01.  (Thanks to
   1514     Alois Treindl for pointing out that the old data entries were
   1515     probably wrong.)
   1516 
   1517     Fix several errors in pre-1970 transitions in Perry County, IN.
   1518     (Thanks to Alois Treindl for pointing out the 1967/9 errors.)
   1519 
   1520     Edmonton did not observe DST in 1967 or 1969.  In 1946 Vancouver
   1521     ended DST on 09-29 not 10-13, and Vienna ended DST on 10-07 not
   1522     10-06.  In 1945 Knigsberg (now Kaliningrad) switched from +01/+02
   1523     to +02/+03 on 04-10 not 01-01, and its +02/+03 is abbreviated
   1524     EET/EEST, not CET/CEST.  (Thanks to Alois Treindl.)  In 1946
   1525     Knigsberg switched to +03 on 04-07 not 01-01.
   1526 
   1527     In 1946 Louisville switched from CST to CDT on 04-28 at 00:01, not
   1528     01-01 at 00:00.  (Thanks to Alois Treindl and Michael Deckers.)
   1529     Also, it switched from CST to CDT on 1950-04-30, not 1947-04-27.
   1530 
   1531     The 1892-05-01 transition in Brussels was at 00:17:30, not at noon.
   1532     (Thanks to Michael Deckers.)
   1533 
   1534   Changes to past time zone abbreviations and DST flags
   1535 
   1536     Hong Kong Winter Time, observed from 1941-10-01 to 1941-12-25,
   1537     is now flagged as DST and is abbreviated HKWT not HKT.
   1538 
   1539   Changes to code
   1540 
   1541     leapseconds.awk now relies only on its input data, rather than
   1542     also relying on its comments.  (Inspired by code from Dennis
   1543     Ferguson and Chris Woodbury.)
   1544 
   1545     The code now defends against CRLFs in leap-seconds.list.
   1546     (Thanks to Brian Inglis and Chris Woodbury.)
   1547 
   1548   Changes to documentation and commentary
   1549 
   1550     theory.html discusses leap seconds.  (Thanks to Steve Summit.)
   1551 
   1552     Nashville's newspapers dueled about the time of day in the 1950s.
   1553     (Thanks to John Seigenthaler.)
   1554 
   1555     Liechtenstein observed Swiss DST in 1941/2.
   1556     (Thanks to Alois Treindl.)
   1557 
   1558 
   1559 Release 2019b - 2019-07-01 00:09:53 -0700
   1560 
   1561   Briefly:
   1562     Brazil no longer observes DST.
   1563     'zic -b slim' outputs smaller TZif files; please try it out.
   1564     Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
   1565 
   1566   Changes to future timestamps
   1567 
   1568     Brazil has canceled DST and will stay on standard time indefinitely.
   1569     (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
   1570     Oliveira.)
   1571 
   1572     Predictions for Morocco now go through 2087 instead of 2037, to
   1573     work around a problem on newlib when using TZif files output by
   1574     zic 2019a or earlier.  (Problem reported by David Gauchard.)
   1575 
   1576   Changes to past and future timestamps
   1577 
   1578     Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
   1579     at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
   1580     future transitions to be March's last Friday at 00:00.
   1581 
   1582   Changes to past timestamps
   1583 
   1584     Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
   1585     03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
   1586     not 09-15 at 00:00.  In 1946 its spring-forward transition was on
   1587     04-21 at 00:00, not the previous day at 03:30.  From 1946 through
   1588     1952 its fall-back transitions occurred at 04:30, not at 03:30.
   1589     In 1947 its fall-back transition was on 11-30, not 12-30.
   1590     (Thanks to P Chan.)
   1591 
   1592   Changes to past time zone abbreviations
   1593 
   1594     Italy's 1866 transition to Rome Mean Time was on December 12, not
   1595     September 22.  This affects only the time zone abbreviation for
   1596     Europe/Rome between those dates.  (Thanks to Stephen Trainor and
   1597     Luigi Rosa.)
   1598 
   1599   Changes affecting metadata only
   1600 
   1601     Add info about the Crimea situation in zone1970.tab and zone.tab.
   1602     (Problem reported by Serhii Demediuk.)
   1603 
   1604   Changes to code
   1605 
   1606     zic's new -b option supports a way to control data bloat and to
   1607     test for year-2038 bugs in software that reads TZif files.
   1608     'zic -b fat' and 'zic -b slim' generate larger and smaller output;
   1609     for example, changing from fat to slim shrinks the Europe/London
   1610     file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
   1611     files represent the same set of timestamps and use the same TZif
   1612     format as documented in tzfile(5) and in Internet RFC 8536.
   1613     Fat format attempts to work around bugs or incompatibilities in
   1614     older software, notably software that mishandles 64-bit TZif data
   1615     or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
   1616     Slim format is more efficient and does not work around 64-bit bugs
   1617     or obsolete TZ strings.  Currently zic defaults to fat format
   1618     unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
   1619     out-of-the-box default is intended to change in future releases
   1620     as the buggy software often mishandles timestamps anyway.
   1621 
   1622     zic no longer treats a set of rules ending in 2037 specially.
   1623     Previously, zic assumed that such a ruleset meant that future
   1624     timestamps could not be predicted, and therefore omitted a
   1625     POSIX-like TZ string in the TZif output.  The old behavior is no
   1626     longer needed for current tzdata, and caused problems with newlib
   1627     when used with older tzdata (reported by David Gauchard).
   1628 
   1629     zic no longer generates some artifact transitions.  For example,
   1630     Europe/London no longer has a no-op transition in January 1996.
   1631 
   1632   Changes to build procedure
   1633 
   1634     tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
   1635     by a percent or so.
   1636 
   1637   Changes to documentation and commentary
   1638 
   1639     The Makefile now documents the POSIXRULES macro as being obsolete,
   1640     and similarly, zic's -p POSIXRULES option is now documented as
   1641     being obsolete.  Although the POSIXRULES feature still exists and
   1642     works as before, in practice it is rarely used for its intended
   1643     purpose, and it does not work either in the default reference
   1644     implementation (for timestamps after 2037) or in common
   1645     implementations such as GNU/Linux (for contemporary timestamps).
   1646     Since POSIXRULES was designed primarily as a temporary transition
   1647     facility for System V platforms that died off decades ago, it is
   1648     being decommissioned rather than institutionalized.
   1649 
   1650     New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
   1651 
   1652 
   1653 Release 2019a - 2019-03-25 22:01:33 -0700
   1654 
   1655   Briefly:
   1656     Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
   1657     Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
   1658 
   1659   Changes to past and future timestamps
   1660 
   1661     Palestine will not start DST until 2019-03-30, instead of 2019-03-23 as
   1662     previously predicted.  Adjust our prediction by guessing that spring
   1663     transitions will be between 24 and 30 March, which matches recent practice
   1664     since 2016.  (Thanks to Even Scharning and Tim Parenti.)
   1665 
   1666     Metlakatla ended its observance of Pacific standard time,
   1667     rejoining Alaska Time, on 2019-01-20 at 02:00.  (Thanks to Ryan
   1668     Stanley and Tim Parenti.)
   1669 
   1670   Changes to past timestamps
   1671 
   1672     Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
   1673     (Thanks to Alois Treindl and Isaac Starkman.)
   1674 
   1675   Changes to time zone abbreviations
   1676 
   1677     Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
   1678     of being a separate zone that generates the abbreviation "UCT",
   1679     which nowadays is typically a typo.  (Problem reported by Isiah
   1680     Meadows.)
   1681 
   1682   Changes to code
   1683 
   1684     zic now has an -r option to limit the time range of output data.
   1685     For example, 'zic -r @1000000000' limits the output data to
   1686     timestamps starting 1000000000 seconds after the Epoch.
   1687     This helps shrink output size and can be useful for applications
   1688     not needing the full timestamp history, such as TZDIST truncation;
   1689     see Internet RFC 8536 section 5.1.  (Inspired by a feature request
   1690     from Christopher Wong, helped along by bug reports from Wong and
   1691     from Tim Parenti.)
   1692 
   1693   Changes to documentation
   1694 
   1695     Mention Internet RFC 8536 (February 2019), which documents TZif.
   1696 
   1697     tz-link.html now cites tzdata-meta
   1698     <https://tzdata-meta.timtimeonline.com/>.
   1699 
   1700 
   1701 Release 2018i - 2018-12-30 11:05:43 -0800
   1702 
   1703   Briefly:
   1704     So Tom and Prncipe switches from +01 to +00 on 2019-01-01.
   1705 
   1706   Changes to future timestamps
   1707 
   1708     Due to a change in government, So Tom and Prncipe switches back
   1709     from +01 to +00 on 2019-01-01 at 02:00.  (Thanks to Vadim
   1710     Nasardinov and Michael Deckers.)
   1711 
   1712 
   1713 Release 2018h - 2018-12-23 17:59:32 -0800
   1714 
   1715   Briefly:
   1716     Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
   1717     New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
   1718     Metlakatla, Alaska observes PST this winter only.
   1719     Guess Morocco will continue to adjust clocks around Ramadan.
   1720     Add predictions for Iran from 2038 through 2090.
   1721 
   1722   Changes to future timestamps
   1723 
   1724     Guess that Morocco will continue to fall back just before and
   1725     spring forward just after Ramadan, the practice since 2012.
   1726     (Thanks to Maamar Abdelkader.)  This means Morocco will observe
   1727     negative DST during Ramadan in main and vanguard formats, and in
   1728     rearguard format it stays in the +00 timezone and observes
   1729     ordinary DST in all months other than Ramadan.  As before, extend
   1730     this guesswork to the year 2037.  As a consequence, Morocco is
   1731     scheduled to observe three DST transitions in some Gregorian years
   1732     (e.g., 2033) due to the mismatch between the Gregorian and Islamic
   1733     calendars.
   1734 
   1735     The table of exact transitions for Iranian DST has been extended.
   1736     It formerly cut off before the year 2038 in a nod to 32-bit time_t.
   1737     It now cuts off before 2091 as there is doubt about how the Persian
   1738     calendar will treat 2091.  This change predicts DST transitions in
   1739     2038-9, 2042-3, and 2046-7 to occur one day later than previously
   1740     predicted.  As before, post-cutoff transitions are approximated.
   1741 
   1742   Changes to past and future timestamps
   1743 
   1744     Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
   1745     +05 on 2018-12-21.  This is a zone split as Qostanay (aka
   1746     Kostanay) did not switch, so create a zone Asia/Qostanay.
   1747 
   1748     Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
   1749     It did not change clocks that day and remains on -08 this winter.
   1750     (Thanks to Ryan Stanley.)  It will revert to the usual Alaska
   1751     rules next spring, so this change affects only timestamps
   1752     from 2018-11-04 through 2019-03-10.
   1753 
   1754   Change to past timestamps
   1755 
   1756     Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
   1757     not 00:00.  I transcribed the time incorrectly from Shanks.
   1758     (Thanks to Phake Nick.)
   1759 
   1760     Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
   1761     (Thanks to Phake Nick.)
   1762 
   1763     Guam observed DST irregularly from 1959 through 1977.
   1764     (Thanks to Phake Nick.)
   1765 
   1766     Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
   1767     10-01 changed standard time to +08:30 (not +08).  Its transition
   1768     back to +08 after WWII was on 1945-09-15, not the previous day.
   1769     Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
   1770     (Thanks to Phake Nick, Steve Allen, and Joseph Myers.)  Also,
   1771     its 1952 fallback was on 11-02 (not 10-25).
   1772 
   1773     This release contains many changes to timestamps before 1946 due
   1774     to Japanese possession or occupation of Pacific/Chuuk,
   1775     Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
   1776     Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
   1777     (Thanks to Phake Nick.)
   1778 
   1779     Assume that the Spanish East Indies was like the Philippines and
   1780     observed American time until the end of 1844.  This affects
   1781     Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.
   1782 
   1783   Changes to past tm_isdst flags
   1784 
   1785     For the recent Morocco change, the tm_isdst flag should be 1 from
   1786     2018-10-27 00:00 to 2018-10-28 03:00.  (Thanks to Michael Deckers.)
   1787     Give a URL to the official decree.  (Thanks to Matt Johnson.)
   1788 
   1789 
   1790 Release 2018g - 2018-10-26 22:22:45 -0700
   1791 
   1792   Briefly:
   1793     Morocco switches to permanent +01 on 2018-10-28.
   1794 
   1795   Changes to future timestamps
   1796 
   1797     Morocco switches from +00/+01 to permanent +01 effective 2018-10-28,
   1798     so its clocks will not fall back as previously scheduled.
   1799     (Thanks to Mohamed Essedik Najd and Brian Inglis.)
   1800 
   1801   Changes to code
   1802 
   1803     When generating TZif files with leap seconds, zic no longer uses a
   1804     format that trips up older 32-bit clients, fixing a bug introduced
   1805     in 2018f.  (Reported by Daniel Fischer.)  Also, the zic workaround
   1806     for QTBUG-53071 now also works for TZif files with leap seconds.
   1807 
   1808     The translator to rearguard format now rewrites the line
   1809     "Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S" to
   1810     "Rule Japan 1948 1951 - Sep Sun>=9  1:00 0 S".
   1811     This caters to zic before 2007 and to Oracle TZUpdater 2.2.0
   1812     and earlier.  (Reported by Christos Zoulas.)
   1813 
   1814   Changes to past time zone abbreviations
   1815 
   1816     Change HDT to HWT/HPT for WWII-era abbreviations in Hawaii.
   1817     This reverts to 2011h, as the abbreviation change in 2011i was
   1818     likely inadvertent.
   1819 
   1820   Changes to documentation
   1821 
   1822     tzfile.5 has new sections on interoperability issues.
   1823 
   1824 
   1825 Release 2018f - 2018-10-18 00:14:18 -0700
   1826 
   1827   Briefly:
   1828   Volgograd moves from +03 to +04 on 2018-10-28.
   1829   Fiji ends DST 2019-01-13, not 2019-01-20.
   1830   Most of Chile changes DST dates, effective 2019-04-06.
   1831 
   1832   Changes to future timestamps
   1833 
   1834     Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
   1835     (Thanks to Alexander Fetisov and Stepan Golosunov.)
   1836 
   1837     Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
   1838     predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
   1839     accordingly.
   1840 
   1841     Most of Chile will end DST on the first Saturday in April at 24:00 mainland
   1842     time, and resume DST on the first Saturday in September at 24:00 mainland
   1843     time.  The changes are effective from 2019-04-06, and do not affect the
   1844     Magallanes region modeled by America/Punta_Arenas.  (Thanks to Juan Correa
   1845     and Tim Parenti.)  Adjust future predictions accordingly.
   1846 
   1847   Changes to past timestamps
   1848 
   1849     The 2018-05-05 North Korea 30-minute time zone change took place
   1850     at 23:30 the previous day, not at 00:00 that day.
   1851 
   1852     China's 1988 spring-forward transition was on April 17, not
   1853     April 10.  Its DST transitions in 1986/91 were at 02:00, not 00:00.
   1854     (Thanks to P Chan.)
   1855 
   1856     Fix several issues for Macau before 1992.  Macau's pre-1904 LMT
   1857     was off by 10 s.  Macau switched to +08 in 1904 not 1912, and
   1858     temporarily switched to +09/+10 during World War II.  Macau
   1859     observed DST in 1942/79, not 1961/80, and there were several
   1860     errors for transition times and dates.  (Thanks to P Chan.)
   1861 
   1862     The 1948-1951 fallback transitions in Japan were at 25:00 on
   1863     September's second Saturday, not at 24:00.  (Thanks to Phake Nick.)
   1864     zic turns this into 01:00 on the day after September's second
   1865     Saturday, which is the best that POSIX or C platforms can do.
   1866 
   1867     Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
   1868     paper by Li Yu, replacing more-questionable data from Shanks.
   1869 
   1870   Changes to time zone abbreviations
   1871 
   1872     Use "PST" and "PDT" for Philippine time.  (Thanks to Paul Goyette.)
   1873 
   1874   Changes to code
   1875 
   1876     zic now always generates TZif files where time type 0 is used for
   1877     timestamps before the first transition.  This simplifies the
   1878     reading of TZif files and should not affect behavior of existing
   1879     TZif readers because the same set of time types is used; only
   1880     their internal indexes may have changed.  This affects only the
   1881     legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
   1882     EET, which previously used nonzero types for these timestamps.
   1883 
   1884     Because of the type 0 change, zic no longer outputs a dummy
   1885     transition at time -2**59 (before the Big Bang), as clients should
   1886     no longer need this to handle historical timestamps correctly.
   1887     This reverts a change introduced in 2013d and shrinks most TZif
   1888     files by a few bytes.
   1889 
   1890     zic now supports negative time-of-day in Rule and Leap lines, e.g.,
   1891     "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
   1892     occurs at 18:00 on the Saturday before the last Sunday in April.
   1893     This behavior was documented in 2018a but the code did not
   1894     entirely match the documentation.
   1895 
   1896     localtime.c no longer requires at least one time type in TZif
   1897     files that lack transitions or have a POSIX-style TZ string.  This
   1898     future-proofs the code against possible future extensions to the
   1899     format that would allow TZif files with POSIX-style TZ strings and
   1900     without transitions or time types.
   1901 
   1902     A read-access subscript error in localtime.c has been fixed.
   1903     It could occur only in TZif files with timecnt == 0, something that
   1904     does not happen in practice now but could happen in future versions.
   1905 
   1906     localtime.c no longer ignores TZif POSIX-style TZ strings that
   1907     specify only standard time.  Instead, these TZ strings now
   1908     override the default time type for timestamps after the last
   1909     transition (or for all timestamps if there are no transitions),
   1910     just as DST strings specifying DST have always done.
   1911 
   1912     leapseconds.awk now outputs "#updated" and "#expires" comments,
   1913     and supports leap seconds at the ends of months other than June
   1914     and December.  (Inspired by suggestions from Chris Woodbury.)
   1915 
   1916   Changes to documentation
   1917 
   1918     New restrictions: A Rule name must start with a character that
   1919     is neither an ASCII digit nor "-" nor "+", and an unquoted name
   1920     should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
   1921     The latter restriction makes room for future extensions (a
   1922     possibility noted by Tom Lane).
   1923 
   1924     tzfile.5 now documents what time types apply before the first and
   1925     after the last transition, if any.
   1926 
   1927     Documentation now uses the spelling "timezone" for a TZ setting
   1928     that determines timestamp history, and "time zone" for a
   1929     geographic region currently sharing the same standard time.
   1930 
   1931     The name "TZif" is now used for the tz binary data format.
   1932 
   1933     tz-link.htm now mentions the A0 TimeZone Migration utilities.
   1934     (Thanks to Aldrin Martoq for the link.)
   1935 
   1936   Changes to build procedure
   1937 
   1938     New 'make' target 'rearguard_tarballs' to build the rearguard
   1939     tarball only.  This is a convenience on platforms that lack lzip
   1940     if you want to build the rearguard tarball.  (Problem reported by
   1941     Deborah Goldsmith.)
   1942 
   1943     tzdata.zi is now more stable from release to release.  (Problem
   1944     noted by Tom Lane.)  It is also a bit shorter.
   1945 
   1946     tzdata.zi now can contain comment lines documenting configuration
   1947     information, such as which data format was selected, which input
   1948     files were used, and how leap seconds are treated.  (Problems
   1949     noted by Lester Caine and Brian Inglis.)  If the Makefile defaults
   1950     are used these comment lines are absent, for backward
   1951     compatibility.  A redistributor intending to alter its copy of the
   1952     files should also append "-LABEL" to the 'version' file's first
   1953     line, where "LABEL" identifies the redistributor's change.
   1954 
   1955 
   1956 Release 2018e - 2018-05-01 23:42:51 -0700
   1957 
   1958   Briefly:
   1959 
   1960     North Korea switches back to +09 on 2018-05-05.
   1961     The main format uses negative DST again, for Ireland etc.
   1962     'make tarballs' now also builds a rearguard tarball.
   1963     New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
   1964 
   1965   Changes to past and future timestamps
   1966 
   1967     North Korea switches back from +0830 to +09 on 2018-05-05.
   1968     (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
   1969     and Tim Parenti.)
   1970 
   1971     Bring back the negative-DST changes of 2018a, except be more
   1972     compatible with data parsers that do not support negative DST.
   1973     Also, this now affects historical timestamps in Namibia and the
   1974     former Czechoslovakia, not just Ireland.  The main format now uses
   1975     negative DST to model timestamps in Europe/Dublin (from 1971 on),
   1976     Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
   1977     does not affect UT offsets, only time zone abbreviations and the
   1978     tm_isdst flag.  Also, this does not affect rearguard or vanguard
   1979     formats; effectively the main format now uses vanguard instead of
   1980     rearguard format.  Data parsers that do not support negative DST
   1981     can still use data from the rearguard tarball described below.
   1982 
   1983   Changes to build procedure
   1984 
   1985     The command 'make tarballs' now also builds the tarball
   1986     tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
   1987     except that it uses rearguard format intended for trailing-edge
   1988     data parsers.
   1989 
   1990   Changes to data format and to code
   1991 
   1992     The SAVE column of Rule and Zone lines can now have an 's' or 'd'
   1993     suffix, which specifies whether the adjusted time is standard time
   1994     or daylight saving time.  If no suffix is given, daylight saving
   1995     time is used if and only if the SAVE column is nonzero; this is
   1996     the longstanding behavior.  Although this new feature is not used
   1997     in tzdata, it could be used to specify the legal time in Namibia
   1998     1994-2017, as opposed to the popular time (see below).
   1999 
   2000   Changes to past timestamps
   2001 
   2002     From 1994 through 2017 Namibia observed DST in winter, not summer.
   2003     That is, it used negative DST, as Ireland still does.  This change
   2004     does not affect UTC offsets; it affects only the tm_isdst flag and
   2005     the abbreviation used during summer, which is now CAT, not WAST.
   2006     Although (as noted by Michael Deckers) summer and winter time were
   2007     both simply called "standard time" in Namibian law, in common
   2008     practice winter time was considered to be DST (as noted by Stephen
   2009     Colebourne).  The full effect of this change is only in vanguard
   2010     and main format; in rearguard format, the tm_isdst flag is still
   2011     zero in winter and nonzero in summer.
   2012 
   2013     In 1946/7 Czechoslovakia also observed negative DST in winter.
   2014     The full effect of this change is only in vanguard and main
   2015     formats; in rearguard format, it is modeled as plain GMT without
   2016     daylight saving.  Also, the dates of some 1944/5 DST transitions
   2017     in Czechoslovakia have been changed.
   2018 
   2019 
   2020 Release 2018d - 2018-03-22 07:05:46 -0700
   2021 
   2022   Briefly:
   2023 
   2024   Palestine starts DST a week earlier in 2018.
   2025   Add support for vanguard and rearguard data consumers.
   2026   Add subsecond precision to source data format, though not to data.
   2027 
   2028   Changes to future timestamps
   2029 
   2030     In 2018, Palestine starts DST on March 24, not March 31.
   2031     Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
   2032 
   2033   Changes to past and future timestamps
   2034 
   2035     Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
   2036     at 04:00.  (Thanks to Steffen Thorsen.)
   2037 
   2038   Changes to past timestamps
   2039 
   2040     Historical transitions for Uruguay, represented by
   2041     America/Montevideo, have been updated per official legal documents,
   2042     replacing previous data mainly originating from the inventions of
   2043     Shanks & Pottenger.  This has resulted in adjustments ranging from
   2044     30 to 90 minutes in either direction over at least two dozen
   2045     distinct periods ranging from one day to several years in length.
   2046     A mere handful of pre-1991 transitions are unaffected; data since
   2047     then has come from more reliable contemporaneous reporting.  These
   2048     changes affect various timestamps in 1920-1923, 1936, 1939,
   2049     1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
   2050     Additionally, Uruguay's pre-standard-time UT offset has been
   2051     adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
   2052     match the location of the Observatory of the National Meteorological
   2053     Institute in Montevideo.
   2054     (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
   2055 
   2056     East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
   2057     (Thanks to Kerry Shetline.)
   2058 
   2059     Fix the 1912-01-01 transition for Portugal and its colonies.
   2060     This transition was at 00:00 according to the new UT offset, not
   2061     according to the old one.  Also assume that Cape Verde switched on
   2062     the same date as the rest, not in 1907.  This affects
   2063     Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
   2064     Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
   2065     (Thanks to Michael Deckers.)
   2066 
   2067     Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
   2068     Turks & Caicos.
   2069 
   2070   Changes to past time zone abbreviations
   2071 
   2072     MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
   2073     is no clock change associated with the transition.
   2074 
   2075   Changes to build procedure
   2076 
   2077     The new DATAFORM macro in the Makefile lets the installer choose
   2078     among three source data formats.  The idea is to lessen downstream
   2079     disruption when data formats are improved.
   2080 
   2081     * DATAFORM=vanguard installs from the latest, bleeding-edge
   2082       format.  DATAFORM=main (the default) installs from the format
   2083       used in the 'africa' etc. files.  DATAFORM=rearguard installs
   2084       from a trailing-edge format.  Eventually, elements of today's
   2085       vanguard format should move to the main format, and similarly
   2086       the main format's features should eventually move to the
   2087       rearguard format.
   2088 
   2089     * In the current version, the main and rearguard formats are
   2090       identical and match that of 2018c, so this change does not
   2091       affect default behavior.  The vanguard format currently contains
   2092       one feature not in the main format: negative SAVE values.  This
   2093       improves support for Ireland, which uses Irish Standard Time
   2094       (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
   2095       supported negative SAVE values for decades, and this feature
   2096       should move to the main format soon.  However, it will not move
   2097       to the rearguard format for quite some time because some
   2098       downstream parsers do not support it.
   2099 
   2100     * The build procedure constructs three files vanguard.zi, main.zi,
   2101       and rearguard.zi, one for each format.  Although the files
   2102       represent essentially the same data, they may have minor
   2103       discrepancies that users are not likely to notice.  The files
   2104       are intended for downstream data consumers and are not
   2105       installed.  Zoneinfo parsers that do not support negative SAVE values
   2106       should start using rearguard.zi, so that they will be unaffected
   2107       when the negative-DST feature moves from vanguard to main.
   2108       Bleeding-edge Zoneinfo parsers that support the new features
   2109       already can use vanguard.zi; in this respect, current tzcode is
   2110       bleeding-edge.
   2111 
   2112     The Makefile should now be safe for parallelized builds, and 'make
   2113     -j to2050new.tzs' is now much faster on a multiprocessor host
   2114     with GNU Make.
   2115 
   2116     When built with -DSUPPRESS_TZDIR, the tzcode library no longer
   2117     prepends TZDIR/ to file names that do not begin with '/'.  This is
   2118     not recommended for general use, due to its security implications.
   2119     (From a suggestion by Manuela Friedrich.)
   2120 
   2121   Changes to code
   2122 
   2123     zic now accepts subsecond precision in expressions like
   2124     00:19:32.13, which is approximately the legal time of the
   2125     Netherlands from 1835 to 1937.  However, because it is
   2126     questionable whether the few recorded uses of non-integer offsets
   2127     had subsecond precision in practice, there are no plans for tzdata
   2128     to use this feature.  (Thanks to Steve Allen for pointing out
   2129     the limitations of historical data in this area.)
   2130 
   2131     The code is a bit more portable to MS-Windows.  Installers can
   2132     compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
   2133     reserve identifiers like 'localtime'.  (Thanks to Manuela
   2134     Friedrich.)
   2135 
   2136   Changes to documentation and commentary
   2137 
   2138     theory.html now outlines tzdb's extensions to POSIX's model for
   2139     civil time, and has a section "POSIX features no longer needed"
   2140     that lists POSIX API components that are now vestigial.
   2141     (From suggestions by Steve Summit.)  It also better distinguishes
   2142     time zones from tz regions.  (From a suggestion by Guy Harris.)
   2143 
   2144     Commentary is now more consistent about using the phrase "daylight
   2145     saving time", to match the C name tm_isdst.  Daylight saving time
   2146     need not occur in summer, and need not have a positive offset from
   2147     standard time.
   2148 
   2149     Commentary about historical transitions in Uruguay has been expanded
   2150     with links to many relevant legal documents.
   2151     (Thanks to Tim Parenti.)
   2152 
   2153     Commentary now uses some non-ASCII characters with Unicode value
   2154     less than U+0100, as they can be useful and should work even with
   2155     older editors such as XEmacs.
   2156 
   2157 
   2158 Release 2018c - 2018-01-22 23:00:44 -0800
   2159 
   2160   Briefly:
   2161   Revert Irish changes that relied on negative SAVE values.
   2162 
   2163   Changes to tm_isdst
   2164 
   2165     Revert the 2018a change to Europe/Dublin.  As before, this change
   2166     does not affect UT offsets or abbreviations; it affects only
   2167     whether timestamps are considered to be standard time or
   2168     daylight-saving time, as expressed in the tm_isdst flag of C's
   2169     struct tm type.  This reversion is intended to be a temporary
   2170     workaround for problems discovered with downstream uses of
   2171     releases 2018a and 2018b, which implemented Irish time by using
   2172     negative SAVE values in the Eire rules of the 'europe' file.
   2173     Although negative SAVE values have been part of tzcode for many
   2174     years and are supported by many platforms, they were not
   2175     documented before 2018a and ICU and OpenJDK do not currently
   2176     support them.  A mechanism to export data to platforms lacking
   2177     support for negative DST is planned to be developed before the
   2178     change is reapplied.  (Problems reported by Deborah Goldsmith and
   2179     Stephen Colebourne.)
   2180 
   2181   Changes to past timestamps
   2182 
   2183     Japanese DST transitions (1948-1951) were Sundays at 00:00, not
   2184     Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
   2185 
   2186   Changes to build procedure
   2187 
   2188     The build procedure now works around mawk 1.3.3's lack of support
   2189     for character class expressions.  (Problem reported by Ohyama.)
   2190 
   2191 
   2192 Release 2018b - 2018-01-17 23:24:48 -0800
   2193 
   2194   Briefly:
   2195   Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
   2196 
   2197   Changes to build procedure
   2198 
   2199     The distribution now contains the file 'pacificnew' again.
   2200     This file was inadvertently omitted in the 2018a distribution.
   2201     (Problem reported by Matias Fonzo.)
   2202 
   2203 
   2204 Release 2018a - 2018-01-12 22:29:21 -0800
   2205 
   2206   Briefly:
   2207   So Tom and Prncipe switched from +00 to +01.
   2208   Brazil's DST will now start on November's first Sunday.
   2209   Ireland's standard time is now in the summer, not the winter.
   2210   Use Debian-style installation locations, instead of 4.3BSD-style.
   2211   New zic option -t.
   2212 
   2213   Changes to past and future timestamps
   2214 
   2215     So Tom and Prncipe switched from +00 to +01 on 2018-01-01 at
   2216     01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
   2217 
   2218   Changes to future timestamps
   2219 
   2220     Starting in 2018 southern Brazil will begin DST on November's
   2221     first Sunday instead of October's third Sunday.  (Thanks to
   2222     Steffen Thorsen.)
   2223 
   2224   Changes to past timestamps
   2225 
   2226     A discrepancy of 4 s in timestamps before 1931 in South Sudan has
   2227     been corrected.  The 'backzone' and 'zone.tab' files did not agree
   2228     with the 'africa' and 'zone1970.tab' files.  (Problem reported by
   2229     Michael Deckers.)
   2230 
   2231     The abbreviation invented for Bolivia Summer Time (1931-2) is now
   2232     BST instead of BOST, to be more consistent with the convention
   2233     used for Latvian Summer Time (1918-9) and for British Summer Time.
   2234 
   2235   Changes to tm_isdst
   2236 
   2237     Change Europe/Dublin so that it observes Irish Standard Time (UT
   2238     +01) in summer and GMT (as negative daylight-saving) in winter,
   2239     instead of observing standard time (GMT) in winter and Irish
   2240     Summer Time (UT +01) in summer.  This change does not affect UT
   2241     offsets or abbreviations; it affects only whether timestamps are
   2242     considered to be standard time or daylight-saving time, as
   2243     expressed in the tm_isdst flag of C's struct tm type.
   2244     (Discrepancy noted by Derick Rethans.)
   2245 
   2246   Changes to build procedure
   2247 
   2248     The default installation locations have been changed to mostly
   2249     match Debian circa 2017, instead of being designed as an add-on to
   2250     4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
   2251     TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
   2252     USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
   2253     locations more precisely.  (This responds to suggestions from
   2254     Brian Inglis and from Steve Summit.)
   2255 
   2256     The default installation procedure no longer creates the
   2257     backward-compatibility link US/Pacific-New, which causes
   2258     confusion during user setup (e.g., see Debian bug 815200).
   2259     Use 'make BACKWARD="backward pacificnew"' to create the link
   2260     anyway, for now.  Eventually we plan to remove the link entirely.
   2261 
   2262     tzdata.zi now contains a version-number comment.
   2263     (Suggested by Tom Lane.)
   2264 
   2265     The Makefile now quotes values like BACKWARD more carefully when
   2266     passing them to the shell.  (Problem reported by Zefram.)
   2267 
   2268     Builders no longer need to specify -DHAVE_SNPRINTF on platforms
   2269     that have snprintf and use pre-C99 compilers.  (Problem reported
   2270     by Jon Skeet.)
   2271 
   2272   Changes to code
   2273 
   2274     zic has a new option -t FILE that specifies the location of the
   2275     file that determines local time when TZ is unset.  The default for
   2276     this location can be configured via the new TZDEFAULT makefile
   2277     macro, which defaults to /etc/localtime.
   2278 
   2279     Diagnostics and commentary now distinguish UT from UTC more
   2280     carefully; see theory.html for more information about UT vs UTC.
   2281 
   2282     zic has been ported to GCC 8's -Wstringop-truncation option.
   2283     (Problem reported by Martin Sebor.)
   2284 
   2285   Changes to documentation and commentary
   2286 
   2287     The zic man page now documents the longstanding behavior that
   2288     times and years can be out of the usual range, with negative times
   2289     counting backwards from midnight and with year 0 preceding year 1.
   2290     (Problem reported by Michael Deckers.)
   2291 
   2292     The theory.html file now mentions the POSIX limit of six chars
   2293     per abbreviation, and lists alphabetic abbreviations used.
   2294 
   2295     The files tz-art.htm and tz-link.htm have been renamed to
   2296     tz-art.html and tz-link.html, respectively, for consistency with
   2297     other file names and to simplify web server configuration.
   2298 
   2299 
   2300 Release 2017c - 2017-10-20 14:49:34 -0700
   2301 
   2302   Briefly:
   2303   Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
   2304   Fiji ends DST 2018-01-14, not 2018-01-21.
   2305   Namibia switches from +01/+02 to +02 on 2018-04-01.
   2306   Sudan switches from +03 to +02 on 2017-11-01.
   2307   Tonga likely switches from +13/+14 to +13 on 2017-11-05.
   2308   Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
   2309   A new file tzdata.zi now holds a small text copy of all data.
   2310   The zic input format has been regularized slightly.
   2311 
   2312   Changes to future timestamps
   2313 
   2314     Northern Cyprus has decided to resume EU rules starting
   2315     2017-10-29, thus reinstituting winter time.
   2316 
   2317     Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
   2318     predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
   2319     accordingly.
   2320 
   2321     Namibia will switch from +01 with DST to +02 all year on
   2322     2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
   2323     at 02:00.  (Thanks to Steffen Thorsen.)
   2324 
   2325     Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
   2326     Atyya and Yahia Abdalla.)  South Sudan is not switching, so
   2327     Africa/Juba is no longer a link to Africa/Khartoum.
   2328 
   2329     Tonga has likely ended its experiment with DST, and will not
   2330     adjust its clocks on 2017-11-05.  Although Tonga has not announced
   2331     whether it will continue to observe DST, the IATA is assuming that
   2332     it will not.  (Thanks to David Wade.)
   2333 
   2334     Turks & Caicos will switch from -04 all year to -05 with US DST on
   2335     2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
   2336     at 02:00.  (Thanks to Steffen Thorsen.)
   2337 
   2338   Changes to past timestamps
   2339 
   2340     Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
   2341     (Thanks to Arthur David Olson.)
   2342 
   2343     Detroit did not observe DST in 1967.
   2344 
   2345     Use railway time for Asia/Kolkata before 1941, by switching to
   2346     Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
   2347     1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
   2348 
   2349     Europe/Dublin's 1946 and 1947 fallback transitions occurred at
   2350     02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
   2351 
   2352     Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
   2353     American time in 1892, not 1879.  (Thanks to Michael Deckers.)
   2354 
   2355     Adjust the 1867 transition in Alaska to better reflect the
   2356     historical record, by changing it to occur on 1867-10-18 at 15:30
   2357     Sitka time rather than at the start of 1867-10-17 local time.
   2358     Although strictly speaking this is accurate only for Sitka,
   2359     the rest of Alaska's blanks need to be filled in somehow.
   2360 
   2361     Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
   2362     (Thanks to Michael Deckers.)
   2363 
   2364     Add 7 s to the UT offset in Asia/Yangon before 1920.
   2365 
   2366   Changes to zone names
   2367 
   2368     Remove Canada/East-Saskatchewan from the 'backward' file, as it
   2369     exceeded the 14-character limit and was an unused misnomer anyway.
   2370 
   2371   Changes to build procedure
   2372 
   2373     To support applications that prefer to read time zone data in text
   2374     form, two zic input files tzdata.zi and leapseconds are now
   2375     installed by default.  The commands 'zic tzdata.zi' and 'zic -L
   2376     leapseconds tzdata.zi' can reproduce the tzdata binary files
   2377     without and with leap seconds, respectively.  To prevent these two
   2378     new files from being installed, use 'make TZDATA_TEXT=', and to
   2379     suppress leap seconds from the tzdata text installation, use 'make
   2380     TZDATA_TEXT=tzdata.zi'.
   2381 
   2382     'make BACKWARD=' now suppresses backward-compatibility names
   2383     like 'US/Pacific' that are defined in the 'backward' and
   2384     'pacificnew' files.
   2385 
   2386     'make check' now works on systems that lack a UTF-8 locale,
   2387     or that lack the nsgmls program.  Set UTF8_LOCALE to configure
   2388     the name of a UTF-8 locale, if you have one.
   2389 
   2390     Y2K runtime checks are no longer enabled by default.  Add
   2391     -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
   2392     adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
   2393     to disable them.  (New name suggested by Brian Inglis.)
   2394 
   2395     The build procedure for zdump now works on AIX 7.1.
   2396     (Problem reported by Kees Dekker.)
   2397 
   2398   Changes to code
   2399 
   2400     zic and the reference runtime now reject multiple leap seconds
   2401     within 28 days of each other, or leap seconds before the Epoch.
   2402     As a result, support for double leap seconds, which was
   2403     obsolescent and undocumented, has been removed.  Double leap
   2404     seconds were an error in the C89 standard; they have never existed
   2405     in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
   2406     noticing glitches in the code that uncovered this problem.)
   2407 
   2408     zic now warns about use of the obsolescent and undocumented -y
   2409     option, and about use of the obsolescent TYPE field of Rule lines.
   2410 
   2411     zic now allows unambiguous abbreviations like "Sa" and "Su" for
   2412     weekdays; formerly it rejected them due to a bug.  Conversely, zic
   2413     no longer considers non-prefixes to be abbreviations; for example,
   2414     it no longer accepts "lF" as an abbreviation for "lastFriday".
   2415     Also, zic warns about the undocumented usage with a "last-"
   2416     prefix, e.g., "last-Fri".
   2417 
   2418     Similarly, zic now accepts the unambiguous abbreviation "L" for
   2419     "Link" in ordinary context and for "Leap" in leap-second context.
   2420     Conversely, zic no longer accepts non-prefixes such as "La" as
   2421     abbreviations for words like "Leap".
   2422 
   2423     zic no longer accepts leap second lines in ordinary input, or
   2424     ordinary lines in leap second input.  Formerly, zic sometimes
   2425     warned about this undocumented usage and handled it incorrectly.
   2426 
   2427     The new macro HAVE_TZNAME governs whether the tzname external
   2428     variable is exported, instead of USG_COMPAT.  USG_COMPAT now
   2429     governs only the external variables "timezone" and "daylight".
   2430     This change is needed because the three variables are not in the
   2431     same category: although POSIX requires tzname, it specifies the
   2432     other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
   2433     if not defined, the code attempts to guess it from other macros.
   2434 
   2435     localtime.c and difftime.c no longer require stdio.h, and .c files
   2436     other than zic.c no longer require sys/wait.h.
   2437 
   2438     zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
   2439 
   2440     Calculation of time_t extrema works around a bug in GCC 4.8.4
   2441     (Reported by Stan Shebs and Joseph Myers.)
   2442 
   2443     zic.c no longer mistranslates formats of line numbers in non-English
   2444     locales.  (Problem reported by Benno Schulenberg.)
   2445 
   2446     Several minor changes have been made to the code to make it a
   2447     bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
   2448     Dekker for reporting the problems.)
   2449 
   2450   Changes to documentation and commentary
   2451 
   2452     The two new files 'theory.html' and 'calendars' contain the
   2453     contents of the removed file 'Theory'.  The goal is to document
   2454     tzdb theory more accessibly.
   2455 
   2456     The zic man page now documents abbreviation rules.
   2457 
   2458     tz-link.htm now covers how to apply tzdata changes to clients.
   2459     (Thanks to Jorge Fbregas for the AIX link.)  It also mentions MySQL.
   2460 
   2461     The leap-seconds.list URL has been updated to something that is
   2462     more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
   2463 
   2464 Release 2017b - 2017-03-17 07:30:38 -0700
   2465 
   2466   Briefly: Haiti has resumed DST.
   2467 
   2468   Changes to past and future timestamps
   2469 
   2470     Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
   2471 
   2472   Changes to past timestamps
   2473 
   2474     Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
   2475 
   2476     Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
   2477     is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
   2478 
   2479   Changes to code
   2480 
   2481     The reference localtime implementation now falls back on the
   2482     current US daylight-saving transition rules rather than the
   2483     1987-2006 rules.  This fallback occurs only when (1) the TZ
   2484     environment variable has a value like "AST4ADT" that asks
   2485     for daylight saving time but does not specify the rules, (2) there
   2486     is no file by that name, and (3) the TZDEFRULES file cannot be
   2487     loaded.  (Thanks to Tom Lane.)
   2488 
   2489 
   2490 Release 2017a - 2017-02-28 00:05:36 -0800
   2491 
   2492   Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
   2493   discontinues DST.
   2494 
   2495   Changes to future timestamps
   2496 
   2497     Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
   2498 
   2499     Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
   2500     Its clocks diverge from America/Santiago starting 2017-05-13 at
   2501     23:00, hiving off a new zone America/Punta_Arenas.  Although the
   2502     Chilean government says this change expires in May 2019, for now
   2503     assume it's permanent.  (Thanks to Juan Correa and Deborah
   2504     Goldsmith.)  This also affects Antarctica/Palmer.
   2505 
   2506   Changes to past timestamps
   2507 
   2508     Fix many entries for historical timestamps for Europe/Madrid
   2509     before 1979, to agree with tables compiled by Pere Planesas of the
   2510     National Astronomical Observatory of Spain.  As a side effect,
   2511     this changes some timestamps for Africa/Ceuta before 1929, which
   2512     are probably guesswork anyway.  (Thanks to Steve Allen and
   2513     Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
   2514     correcting the 1901 transition.)
   2515 
   2516     Ecuador observed DST from 1992-11-28 to 1993-02-05.
   2517     (Thanks to Alois Treindl.)
   2518 
   2519     Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
   2520     (Thanks to Stepan Golosunov.)
   2521 
   2522   Changes to past and future time zone abbreviations
   2523 
   2524     Switch to numeric time zone abbreviations for South America, as
   2525     part of the ongoing project of removing invented abbreviations.
   2526     This avoids the need to invent an abbreviation for the new Chilean
   2527     new zone.  Similarly, switch from invented to numeric time zone
   2528     abbreviations for Afghanistan, American Samoa, the Azores,
   2529     Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
   2530     Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
   2531     Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
   2532     Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
   2533     the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
   2534     Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
   2535     Papua New Guinea, the Philippines, Pitcairn, Qatar, Runion, St
   2536     Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
   2537     Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
   2538     Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
   2539     for half-hour daylight saving time in Belize before 1944 and in
   2540     the Dominican Republic before 1975; and for Canary Islands before
   2541     1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
   2542     Indian Summer Time before 1942, for Indonesia before around 1964,
   2543     for Kenya before 1960, for Liberia before 1973, for Madeira before
   2544     1967, for Namibia before 1943, for the Netherlands in 1937-9, for
   2545     Pakistan before 1971, for Western Sahara before 1977, and for
   2546     Zaporozhye in 1880-1924.
   2547 
   2548     For Alaska time from 1900 through 1967, instead of "CAT" use the
   2549     abbreviation "AST", the abbreviation commonly used at the time
   2550     (Atlantic Standard Time had not been standardized yet).  Use "AWT"
   2551     and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
   2552 
   2553     Use "CST" and "CDT" instead of invented abbreviations for Macau
   2554     before 1999 and Taiwan before 1938, and use "JST" instead of the
   2555     invented abbreviation "JCST" for Japan and Korea before 1938.
   2556 
   2557   Change to database entry category
   2558 
   2559     Move the Pacific/Johnston link from 'australasia' to 'backward',
   2560     since Johnston is now uninhabited.
   2561 
   2562   Changes to code
   2563 
   2564     zic no longer mishandles some transitions in January 2038 when it
   2565     attempts to work around Qt bug 53071.  This fixes a bug affecting
   2566     Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
   2567     now contains a workaround, useful when loading a file generated by
   2568     a buggy zic.  (Problem and localtime.c fix reported by Bradley
   2569     White.)
   2570 
   2571     zdump -i now outputs non-hour numeric time zone abbreviations
   2572     without a colon, e.g., "+0530" rather than "+05:30".  This agrees
   2573     with zic %z and with common practice, and simplifies auditing of
   2574     zdump output.
   2575 
   2576     zdump is now buildable again with -DUSE_LTZ=0.
   2577     (Problem reported by Joseph Myers.)
   2578 
   2579     zdump.c now always includes private.h, to avoid code duplication
   2580     with private.h.  (Problem reported by Kees Dekker.)
   2581 
   2582     localtime.c no longer mishandles early or late timestamps
   2583     when TZ is set to a POSIX-style string that specifies DST.
   2584     (Problem reported by Kees Dekker.)
   2585 
   2586     date and strftime now cause %z to generate "-0000" instead of
   2587     "+0000" when the UT offset is zero and the time zone abbreviation
   2588     begins with "-".
   2589 
   2590   Changes to documentation and commentary
   2591 
   2592     The 'Theory' file now better documents choice of historical time
   2593     zone abbreviations.  (Problems reported by Michael Deckers.)
   2594 
   2595     tz-link.htm now covers leap smearing, which is popular in clouds.
   2596 
   2597 
   2598 Release 2016j - 2016-11-22 23:17:13 -0800
   2599 
   2600   Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
   2601 
   2602   Changes to future timestamps
   2603 
   2604     Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
   2605     This hives off a new zone Europe/Saratov from Europe/Volgograd.
   2606     (Thanks to Yuri Konotopov and Stepan Golosunov.)
   2607 
   2608   Changes to past timestamps
   2609 
   2610     The new zone Asia/Atyrau for Atyra Region, Kazakhstan, is like
   2611     Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
   2612     1999, not fall 1994.  (Thanks to Stepan Golosunov.)
   2613 
   2614   Changes to past time zone abbreviations
   2615 
   2616     Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
   2617     summer time before 1948.  The old use of "EET" was a typo.
   2618 
   2619   Changes to code
   2620 
   2621     zic no longer mishandles file systems that lack hard links, fixing
   2622     bugs introduced in 2016g.  (Problems reported by Tom Lane.)
   2623     Also, when the destination already contains symbolic links, zic
   2624     should now work better on systems where the 'link' system call
   2625     does not follow symbolic links.
   2626 
   2627   Changes to documentation and commentary
   2628 
   2629     tz-link.htm now documents the relationship between release version
   2630     numbers and development-repository commit tags.  (Suggested by
   2631     Paul Koning.)
   2632 
   2633     The 'Theory' file now documents UT.
   2634 
   2635     iso3166.tab now accents "Curaao", and commentary now mentions
   2636     the names "Cabo Verde" and "Czechia".  (Thanks to Ji Boh.)
   2637 
   2638 
   2639 Release 2016i - 2016-11-01 23:19:52 -0700
   2640 
   2641   Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
   2642   reintroduces DST on 2016-11-06.
   2643 
   2644   Changes to future timestamps
   2645 
   2646     Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
   2647     2017-01-15 at 03:00.  Assume future observances in Tonga will be
   2648     from the first Sunday in November through the third Sunday in
   2649     January, like Fiji.  (Thanks to Pulu Anau.)  Switch to numeric
   2650     time zone abbreviations for this zone.
   2651 
   2652   Changes to past and future timestamps
   2653 
   2654     Northern Cyprus is now +03 year round, causing a split in Cyprus
   2655     time zones starting 2016-10-30 at 04:00.  This creates a zone
   2656     Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
   2657 
   2658     Antarctica/Casey switched from +08 to +11 on 2016-10-22.
   2659     (Thanks to Steffen Thorsen.)
   2660 
   2661   Changes to past timestamps
   2662 
   2663     Several corrections were made for pre-1975 timestamps in Italy.
   2664     These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
   2665     Europe/Vatican.
   2666 
   2667     First, the 1893-11-01 00:00 transition in Italy used the new UT
   2668     offset (+01), not the old (+00:49:56).  (Thanks to Michael
   2669     Deckers.)
   2670 
   2671     Second, rules for daylight saving in Italy were changed to agree
   2672     with Italy's National Institute of Metrological Research (INRiM)
   2673     except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
   2674     Inglis, and Michael Deckers):
   2675 
   2676       The 1916-06-03 transition was at 24:00, not 00:00.
   2677 
   2678       The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
   2679       00:00, not 01:00.
   2680 
   2681       The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
   2682       01:00.
   2683 
   2684       The 1944-09-17 transition was at 03:00, not 01:00.  This
   2685       particular change is taken from Italian law as INRiM's table,
   2686       (which says 02:00) appears to have a typo here.  Also, keep the
   2687       1944-04-03 transition for Europe/Rome, as Rome was controlled by
   2688       Germany then.
   2689 
   2690       The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
   2691       not 00:00.
   2692 
   2693   Changes to code
   2694 
   2695     The code should now be buildable on AmigaOS merely by setting the
   2696     appropriate Makefile variables.  (From a patch by Carsten Larsen.)
   2697 
   2698 
   2699 Release 2016h - 2016-10-19 23:17:57 -0700
   2700 
   2701   Changes to future timestamps
   2702 
   2703     Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
   2704     2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
   2705     future fall transitions will be on the last Saturday of October
   2706     at 01:00, which is consistent with predicted spring transitions
   2707     on the last Saturday of March.  (Thanks to Tim Parenti.)
   2708 
   2709   Changes to past timestamps
   2710 
   2711     In Turkey, transitions in 1986-1990 were at 01:00 standard time
   2712     not at 02:00, and the spring 1994 transition was on March 20, not
   2713     March 27.  (Thanks to Kvan Yazan.)
   2714 
   2715   Changes to past and future time zone abbreviations
   2716 
   2717     Asia/Colombo now uses numeric time zone abbreviations like "+0530"
   2718     instead of alphabetic ones like "IST" and "LKT".  Various
   2719     English-language sources use "IST", "LKT" and "SLST", with no
   2720     working consensus.  (Usage of "SLST" mentioned by Sadika
   2721     Sumanapala.)
   2722 
   2723   Changes to code
   2724 
   2725     zic no longer mishandles relativizing file names when creating
   2726     symbolic links like /etc/localtime, when these symbolic links
   2727     are outside the usual directory hierarchy.  This fixes a bug
   2728     introduced in 2016g.  (Problem reported by Andreas Stieger.)
   2729 
   2730   Changes to build procedure
   2731 
   2732     New rules 'traditional_tarballs' and 'traditional_signatures' for
   2733     building just the traditional-format distribution.  (Requested by
   2734     Deborah Goldsmith.)
   2735 
   2736     The file 'version' is now put into the tzdata tarball too.
   2737     (Requested by Howard Hinnant.)
   2738 
   2739   Changes to documentation and commentary
   2740 
   2741     The 'Theory' file now has a section on interface stability.
   2742     (Requested by Paul Koning.)  It also mentions features like
   2743     tm_zone and localtime_rz that have long been supported by the
   2744     reference code.
   2745 
   2746     tz-link.htm has improved coverage of time zone boundaries suitable
   2747     for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
   2748     Johnson.)
   2749 
   2750     The US commentary now mentions Allen and the "day of two noons".
   2751 
   2752     The Fiji commentary mentions the government's 2016-10-03 press
   2753     release.  (Thanks to Raymond Kumar.)
   2754 
   2755 
   2756 Release 2016g - 2016-09-13 08:56:38 -0700
   2757 
   2758   Changes to future timestamps
   2759 
   2760     Turkey switched from EET/EEST (+02/+03) to permanent +03,
   2761     effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
   2762     than an invented abbreviation for the new time.
   2763 
   2764     New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
   2765     (Thanks to Tim Parenti.)
   2766 
   2767   Changes to past timestamps
   2768 
   2769     For America/Los_Angeles, spring-forward transition times have been
   2770     corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
   2771     1950-1966.
   2772 
   2773     For zones using Soviet time on 1919-07-01, transitions to UT-based
   2774     time were at 00:00 UT, not at 02:00 local time.  The affected
   2775     zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
   2776     Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
   2777 
   2778   Changes to past and future time zone abbreviations
   2779 
   2780     The Factory zone now uses the time zone abbreviation -00 instead
   2781     of a long English-language string, as -00 is now the normal way to
   2782     represent an undefined time zone.
   2783 
   2784     Several zones in Antarctica and the former Soviet Union, along
   2785     with zones intended for ships at sea that cannot use POSIX TZ
   2786     strings, now use numeric time zone abbreviations instead of
   2787     invented or obsolete alphanumeric abbreviations.  The affected
   2788     zones are Antarctica/Casey, Antarctica/Davis,
   2789     Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
   2790     Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
   2791     Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
   2792     Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
   2793     Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
   2794     Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
   2795     Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
   2796     Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
   2797     Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
   2798     Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
   2799     Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
   2800     Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
   2801     Europe/Minsk, Europe/Samara, Europe/Volgograd, and
   2802     Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
   2803     was replaced by +05, whereas MSK and MSD were kept as they are not
   2804     our invention and are widely used.
   2805 
   2806   Changes to zone names
   2807 
   2808     Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
   2809     (Thanks to David Massoud.)
   2810 
   2811   Changes to code
   2812 
   2813     zic no longer generates binary files containing POSIX TZ-like
   2814     strings that disagree with the local time type after the last
   2815     explicit transition in the data.  This fixes a bug with
   2816     Africa/Casablanca and Africa/El_Aaiun in some year-2037 timestamps
   2817     on the reference platform.  (Thanks to Alexander Belopolsky for
   2818     reporting the bug and suggesting a way forward.)
   2819 
   2820     If the installed localtime and/or posixrules files are symbolic
   2821     links, zic now keeps them symbolic links when updating them, for
   2822     compatibility with platforms like OpenSUSE where other programs
   2823     configure these files as symlinks.
   2824 
   2825     zic now avoids hard linking to symbolic links, avoids some
   2826     unnecessary mkdir and stat system calls, and uses shorter file
   2827     names internally.
   2828 
   2829     zdump has a new -i option to generate transitions in a
   2830     smaller but still human-readable format.  This option is
   2831     experimental, and the output format may change in future versions.
   2832     (Thanks to Jon Skeet for suggesting that an option was needed,
   2833     and thanks to Tim Parenti and Chris Rovick for further comments.)
   2834 
   2835   Changes to build procedure
   2836 
   2837     An experimental distribution format is available, in addition
   2838     to the traditional format which will continue to be distributed.
   2839     The new format is a tarball tzdb-VERSION.tar.lz with signature
   2840     file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
   2841     tzdb-VERSION containing the code and data of the traditional
   2842     two-tarball format, along with extra data that may be useful.
   2843     (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
   2844     for comments about the experimental format.)
   2845 
   2846     The release version number is now more accurate in the usual case
   2847     where releases are built from a Git repository.  For example, if
   2848     23 commits and some working-file changes have been made since
   2849     release 2016g, the version number is now something like
   2850     '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
   2851     Tagged releases use the same version number format as before,
   2852     e.g., '2016g'.  To support the more accurate version number, its
   2853     specification has moved from a line in the Makefile to a new
   2854     source file 'version'.
   2855 
   2856     The experimental distribution contains a file to2050.tzs that
   2857     contains what should be the output of 'zdump -i -c 2050' on
   2858     primary zones.  If this file is available, 'make check' now checks
   2859     that zdump generates this output.
   2860 
   2861     'make check_web' now works on Fedora-like distributions.
   2862 
   2863   Changes to documentation and commentary
   2864 
   2865     tzfile.5 now documents the new restriction on POSIX TZ-like
   2866     strings that is now implemented by zic.
   2867 
   2868     Comments now cite URLs for some 1917-1921 Russian DST decrees.
   2869     (Thanks to Alexander Belopolsky.)
   2870 
   2871     tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
   2872     (thanks to Meno Hochschild) and ThreeTen-Extra, and its
   2873     description of Java 8 has been brought up to date (thanks to
   2874     Stephen Colebourne).  Its description of local time on Mars has
   2875     been updated to match current practice, and URLs have been updated
   2876     and some obsolete ones removed.
   2877 
   2878 
   2879 Release 2016f - 2016-07-05 16:26:51 +0200
   2880 
   2881   Changes affecting future timestamps
   2882 
   2883     The Egyptian government changed its mind on short notice, and
   2884     Africa/Cairo will not introduce DST starting 2016-07-07 after all.
   2885     (Thanks to Mina Samuel.)
   2886 
   2887     Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
   2888     (Thanks to Stepan Golosunov.)
   2889 
   2890   Changes to past and future timestamps
   2891 
   2892     Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
   2893     abbreviations instead of invented ones.
   2894 
   2895   Changes affecting past timestamps
   2896 
   2897     Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
   2898     (Thanks to Stepan Golosunov.)
   2899 
   2900 
   2901 Release 2016e - 2016-06-14 08:46:16 -0700
   2902 
   2903   Changes affecting future timestamps
   2904 
   2905     Africa/Cairo observes DST in 2016 from July 7 to the end of October.
   2906     Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
   2907     For future years, guess April's last Thursday to October's last
   2908     Thursday except for Ramadan.
   2909 
   2910   Changes affecting past timestamps
   2911 
   2912     Locations while uninhabited now use '-00', not 'zzz', as a
   2913     placeholder time zone abbreviation.  This is inspired by Internet
   2914     RFC 3339 and is more consistent with numeric time zone
   2915     abbreviations already used elsewhere.  The change affects several
   2916     arctic and antarctic locations, e.g., America/Cambridge_Bay before
   2917     1920 and Antarctica/Troll before 2005.
   2918 
   2919     Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
   2920     at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
   2921 
   2922   Changes to code
   2923 
   2924     zic now outputs a dummy transition at time 2**31 - 1 in zones
   2925     whose POSIX-style TZ strings contain a '<'.  This mostly works
   2926     around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
   2927     (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
   2928 
   2929   Changes affecting documentation and commentary
   2930 
   2931     tz-link.htm says why governments should give plenty of notice for
   2932     time zone or DST changes, and refers to Matt Johnson's blog post.
   2933 
   2934     tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
   2935 
   2936 
   2937 Release 2016d - 2016-04-17 22:50:29 -0700
   2938 
   2939   Changes affecting future timestamps
   2940 
   2941     America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
   2942     (Thanks to Alexander Krivenyshev for the heads-up.)
   2943 
   2944     Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
   2945     (Thanks to Alexander Krivenyshev and Matt Johnson.)
   2946 
   2947     New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
   2948     Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
   2949     at 02:00.  (Thanks to Stepan Golosunov.)
   2950 
   2951   Changes affecting past timestamps
   2952 
   2953     New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
   2954     Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
   2955     1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
   2956     the same change.  (Thanks to Stepan Golosunov.)
   2957 
   2958     Russia and nearby locations had daylight-saving transitions on
   2959     1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
   2960     1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
   2961     Golosunov.)
   2962 
   2963     Many corrections to historical time in Kazakhstan from 1991
   2964     through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
   2965     invented time zone abbreviations with numeric abbreviations.
   2966 
   2967   Changes to commentary
   2968 
   2969     Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
   2970 
   2971 
   2972 Release 2016c - 2016-03-23 00:51:27 -0700
   2973 
   2974   Changes affecting future timestamps
   2975 
   2976     Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
   2977 
   2978     Chile reverts from permanent to seasonal DST.  (Thanks to Juan
   2979     Correa for the heads-up, and to Tim Parenti for corrections.)
   2980     Guess that future transitions are August's and May's second
   2981     Saturdays at 24:00 mainland time.  Also, call the period from
   2982     2014-09-07 through 2016-05-14 daylight saving time instead of
   2983     standard time, as that seems more appropriate now.
   2984 
   2985   Changes affecting past timestamps
   2986 
   2987     Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
   2988     +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
   2989     from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
   2990     (Thanks to Stepan Golosunov.)
   2991 
   2992   Changes to commentary
   2993 
   2994     Several updates and URLs for historical and proposed Russian changes.
   2995     (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
   2996 
   2997 
   2998 Release 2016b - 2016-03-12 17:30:14 -0800
   2999 
   3000   Compatibility note
   3001 
   3002     Starting with release 2016b, some data entries cause zic implementations
   3003     derived from tz releases 2005j through 2015e to issue warnings like
   3004     "time zone abbreviation differs from POSIX standard (+03)".
   3005     These warnings should not otherwise affect zic's output and can safely be
   3006     ignored on today's platforms, as the warnings refer to a restriction in
   3007     POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
   3008     warnings is to upgrade to zic derived from tz releases 2015f and later.
   3009 
   3010   Changes affecting future timestamps
   3011 
   3012     New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
   3013     Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
   3014     2016-03-27 at 02:00 local time.  They need distinct zones since their
   3015     post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
   3016     Altai Republic, Russia, which will switch from +06 to +07 on the same date
   3017     and local time.  The Astrakhan change is already official; the others have
   3018     passed the first reading in the State Duma and are extremely likely.
   3019     Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
   3020     (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
   3021     and Stepan Golosunov for followup.)
   3022 
   3023     As a trial of a new system that needs less information to be made up,
   3024     the new zones use numeric time zone abbreviations like "+04"
   3025     instead of invented abbreviations like "ASTT".
   3026 
   3027     Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
   3028     Steffen Thorsen.)
   3029 
   3030     Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
   3031     (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
   3032     Saturday at 01:00, not March's last Friday at 24:00.
   3033 
   3034   Changes affecting past timestamps
   3035 
   3036     Europe/Chisinau observed DST during 1990, and switched from +04 to
   3037     +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
   3038     (Thanks to Stepan Golosunov.)
   3039 
   3040     1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
   3041     KUYT/KUYST.  (Thanks to Stepan Golosunov.)
   3042 
   3043   Changes to code
   3044 
   3045     tzselect's diagnostics and checking, and checktab.awk's checking,
   3046     have been improved.  (Thanks to J William Piggott.)
   3047 
   3048     tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
   3049 
   3050     tzselect now tests Julian-date TZ settings more accurately.
   3051     (Thanks to J William Piggott.)
   3052 
   3053   Changes to commentary
   3054 
   3055     Comments in zone tables have been improved.  (Thanks to J William Piggott.)
   3056 
   3057     tzselect again limits its menu comments so that menus fit on a
   3058     2480 alphanumeric display.
   3059 
   3060     A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
   3061 
   3062     In the Theory file, the description of possible time zone abbreviations in
   3063     tzdata has been cleaned up, as the old description was unclear and
   3064     inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
   3065 
   3066 
   3067 Release 2016a - 2016-01-26 23:28:02 -0800
   3068 
   3069   Changes affecting future timestamps
   3070 
   3071     America/Cayman will not observe daylight saving this year after all.
   3072     Revert our guess that it would.  (Thanks to Matt Johnson.)
   3073 
   3074     Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
   3075     (Thanks to Alexander Krivenyshev.)
   3076 
   3077     Asia/Tehran now has DST predictions for the year 2038 and later,
   3078     to be March 21 00:00 to September 21 00:00.  This is likely better
   3079     than predicting no DST, albeit off by a day every now and then.
   3080 
   3081   Changes affecting past and future timestamps
   3082 
   3083     America/Metlakatla switched from PST all year to AKST/AKDT on
   3084     2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
   3085 
   3086     America/Santa_Isabel has been removed, and replaced with a
   3087     backward compatibility link to America/Tijuana.  Its contents were
   3088     apparently based on a misreading of Mexican legislation.
   3089 
   3090   Changes affecting past timestamps
   3091 
   3092     Asia/Karachi's two transition times in 2002 were off by a minute.
   3093     (Thanks to Matt Johnson.)
   3094 
   3095   Changes affecting build procedure
   3096 
   3097     An installer can now combine leap seconds with use of the backzone file,
   3098     e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
   3099     The old 'make posix_packrat' rule is now marked as obsolescent.
   3100     (Thanks to Ian Abbott for an initial implementation.)
   3101 
   3102   Changes affecting documentation and commentary
   3103 
   3104     A new file LICENSE makes it easier to see that the code and data
   3105     are mostly public-domain.  (Thanks to James Knight.)  The three
   3106     non-public-domain files now use the current (3-clause) BSD license
   3107     instead of older versions of that license.
   3108 
   3109     tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
   3110     CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
   3111     on editing tz source files (with a mention of Sublime zoneinfo,
   3112     thanks to Gilmore Davidson).
   3113 
   3114     The Theory and asia files now mention the 2015 book "The Global
   3115     Transformation of Time, 1870-1950", and cite a couple of reviews.
   3116 
   3117     The America/Chicago entry now documents the informal use of US
   3118     central time in Fort Pierre, South Dakota.  (Thanks to Rick
   3119     McDermid, Matt Johnson, and Steve Jones.)
   3120 
   3121 
   3122 Release 2015g - 2015-10-01 00:39:51 -0700
   3123 
   3124   Changes affecting future timestamps
   3125 
   3126     Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
   3127     (Thanks to Fatih.)
   3128 
   3129     Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
   3130     (Thanks to Alexander Krivenyshev.)
   3131 
   3132     Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
   3133     (Thanks to Ken Rylander.)
   3134 
   3135     Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
   3136     effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
   3137     New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
   3138 
   3139   Changes affecting past timestamps
   3140 
   3141     Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
   3142 
   3143   Changes affecting code
   3144 
   3145     localtime no longer mishandles America/Anchorage after 2037.
   3146     (Thanks to Bradley White for reporting the bug.)
   3147 
   3148     On hosts with signed 32-bit time_t, localtime no longer mishandles
   3149     Pacific/Fiji after 2038-01-16 14:00 UTC.
   3150 
   3151     The localtime module allows the variables 'timezone', 'daylight',
   3152     and 'altzone' to be in common storage shared with other modules,
   3153     and declares them in case the system <time.h> does not.
   3154     (Problems reported by Kees Dekker.)
   3155 
   3156     On platforms with tm_zone, strftime.c now assumes it is not NULL.
   3157     This simplifies the code and is consistent with zdump.c.
   3158     (Problem reported by Christos Zoulas.)
   3159 
   3160   Changes affecting documentation
   3161 
   3162    The tzfile man page now documents that transition times denote the
   3163    starts (not the ends) of the corresponding time periods.
   3164    (Ambiguity reported by Bill Seymour.)
   3165 
   3166 
   3167 Release 2015f - 2015-08-10 18:06:56 -0700
   3168 
   3169   Changes affecting future timestamps
   3170 
   3171     North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
   3172     The abbreviation remains "KST".  (Thanks to Robert Elz.)
   3173 
   3174     Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
   3175     and Pablo Camargo.)
   3176 
   3177   Changes affecting past and future timestamps
   3178 
   3179     Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
   3180     (Thanks to Roman Tudos.)
   3181 
   3182   Changes affecting data format and code
   3183 
   3184     zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
   3185     field of a Rule line should now be '-'; the old values 'even',
   3186     'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
   3187     Although the implementation has not changed, these features do not
   3188     work in the default installation, they are not used in the data,
   3189     and they are now considered obsolescent.
   3190 
   3191     zic now checks that two rules don't take effect at the same time.
   3192     (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
   3193     simultaneity are now documented.
   3194 
   3195     The two characters '%z' in a zone format now stand for the UT
   3196     offset, e.g., '-07' for seven hours behind UT and '+0530' for
   3197     five hours and thirty minutes ahead.  This better supports time
   3198     zone abbreviations conforming to POSIX.1-2001 and later.
   3199 
   3200   Changes affecting installed data files
   3201 
   3202     Comments for America/Halifax and America/Glace_Bay have been improved.
   3203     (Thanks to Brian Inglis.)
   3204 
   3205     Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
   3206     Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
   3207     installed data files for Europe/Simferopol and Europe/Tallinn.
   3208     It does not affect timestamps.  (Thanks to Howard Hinnant.)
   3209 
   3210   Changes affecting code
   3211 
   3212     zdump and zic no longer warn about valid time zone abbreviations
   3213     like '-05'.
   3214 
   3215     Some Visual Studio 2013 warnings have been suppressed.
   3216     (Thanks to Kees Dekker.)
   3217 
   3218     'date' no longer sets the time of day and its -a, -d, -n and -t
   3219     options have been removed.  Long obsolescent, the implementation
   3220     of these features had porting problems.  Builders no longer need
   3221     to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
   3222     (Thanks to Kees Dekker for pointing out the problem.)
   3223 
   3224   Changes affecting documentation
   3225 
   3226     The Theory file mentions naming issues earlier, as these seem to be
   3227     poorly publicized (thanks to Gilmore Davidson for reporting the problem).
   3228 
   3229     tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
   3230 
   3231     Mention that Herbert Samuel introduced the term "Summer Time".
   3232 
   3233 
   3234 Release 2015e - 2015-06-13 10:56:02 -0700
   3235 
   3236   Changes affecting future timestamps
   3237 
   3238     Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
   3239     not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
   3240 
   3241     Assume Cayman Islands will observe DST starting next year, using US rules.
   3242     Although it isn't guaranteed, it is the most likely.
   3243 
   3244   Changes affecting data format
   3245 
   3246     The file 'iso3166.tab' now uses UTF-8, so that its entries can better
   3247     spell the names of land Islands, Cte d'Ivoire, and Runion.
   3248 
   3249   Changes affecting code
   3250 
   3251     When displaying data, tzselect converts it to the current locale's
   3252     encoding if the iconv command works.  (Problem reported by random832.)
   3253 
   3254     tzselect no longer mishandles Dominica, fixing a bug introduced
   3255     in Release 2014f.  (Problem reported by Owen Leibman.)
   3256 
   3257     zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
   3258     This fixes a bug introduced in Release 2014f.
   3259     (Problem reported by Leonardo Chiquitto.)
   3260 
   3261 
   3262 Release 2015d - 2015-04-24 08:09:46 -0700
   3263 
   3264   Changes affecting future timestamps
   3265 
   3266     Egypt will not observe DST in 2015 and will consider canceling it
   3267     permanently.  For now, assume no DST indefinitely.
   3268     (Thanks to Ahmed Nazmy and Tim Parenti.)
   3269 
   3270   Changes affecting past timestamps
   3271 
   3272     America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
   3273     1966-07-01.  Also, Yukon's time zone history is documented better.
   3274     (Thanks to Brian Inglis and Dennis Ferguson.)
   3275 
   3276   Change affecting past and future time zone abbreviations
   3277 
   3278     The abbreviations for Hawaii-Aleutian standard and daylight times
   3279     have been changed from HAST/HADT to HST/HDT, as per US Government
   3280     Printing Office style.  This affects only America/Adak since 1983,
   3281     as America/Honolulu was already using the new style.
   3282 
   3283   Changes affecting code
   3284 
   3285    zic has some minor performance improvements.
   3286 
   3287 
   3288 Release 2015c - 2015-04-11 08:55:55 -0700
   3289 
   3290   Changes affecting future timestamps
   3291 
   3292     Egypt's spring-forward transition is at 24:00 on April's last Thursday,
   3293     not 00:00 on April's last Friday.  2015's transition will therefore be on
   3294     Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
   3295     apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
   3296 
   3297   Changes affecting past timestamps
   3298 
   3299     The following changes affect some pre-1991 Chile-related timestamps
   3300     in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
   3301 
   3302       The 1910 transition was January 10, not January 1.
   3303 
   3304       The 1918 transition was September 10, not September 1.
   3305 
   3306       The UT -04 time observed from 1932 to 1942 is now considered to
   3307       be standard time, not year-round DST.
   3308 
   3309       Santiago observed DST (UT -03) from 1946-07-15 through
   3310       1946-08-31, then reverted to standard time, then switched to -05
   3311       on 1947-04-01.
   3312 
   3313       Assume transitions before 1968 were at 00:00, since we have no data
   3314       saying otherwise.
   3315 
   3316       The spring 1988 transition was 1988-10-09, not 1988-10-02.
   3317       The fall 1990 transition was 1990-03-11, not 1990-03-18.
   3318 
   3319       Assume no UT offset change for Pacific/Easter on 1890-01-01,
   3320       and omit all transitions on Pacific/Easter from 1942 through 1946
   3321       since we have no data suggesting that they existed.
   3322 
   3323     One more zone has been turned into a link, as it differed
   3324     from an existing zone only for older timestamps.  As usual,
   3325     this change affects UT offsets in pre-1970 timestamps only.
   3326     The zone's old contents have been moved to the 'backzone' file.
   3327     The affected zone is America/Montreal.
   3328 
   3329   Changes affecting commentary
   3330 
   3331     Mention the TZUpdater tool.
   3332 
   3333     Mention "The Time Now".  (Thanks to Brandon Ramsey.)
   3334 
   3335 
   3336 Release 2015b - 2015-03-19 23:28:11 -0700
   3337 
   3338   Changes affecting future timestamps
   3339 
   3340     Mongolia will start observing DST again this year, from the last
   3341     Saturday in March at 02:00 to the last Saturday in September at 00:00.
   3342     (Thanks to Ganbold Tsagaankhuu.)
   3343 
   3344     Palestine will start DST on March 28, not March 27.  Also,
   3345     correct the fall 2014 transition from September 26 to October 24.
   3346     Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
   3347 
   3348   Changes affecting past timestamps
   3349 
   3350     The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
   3351     regression.  (Thanks to Stuart Bishop for reporting the problem.)
   3352 
   3353     Some more zones have been turned into links, when they differed
   3354     from existing zones only for older timestamps.  As usual,
   3355     these changes affect UT offsets in pre-1970 timestamps only.
   3356     Their old contents have been moved to the 'backzone' file.
   3357     The affected zones are: America/Antigua, America/Cayman,
   3358     Pacific/Midway, and Pacific/Saipan.
   3359 
   3360   Changes affecting time zone abbreviations
   3361 
   3362     Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
   3363     (Thanks to Hank W.)
   3364 
   3365   Changes affecting code
   3366 
   3367     Fix integer overflow bug in reference 'mktime' implementation.
   3368     (Problem reported by Jrg Richter.)
   3369 
   3370     Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
   3371     to be used in the same executable as standard-library time_t functions.
   3372     (Problems reported by Bradley White.)
   3373 
   3374   Changes affecting commentary
   3375 
   3376     Cite the recent Mexican decree changing Quintana Roo's time zone.
   3377     (Thanks to Carlos Ral Perasso.)
   3378 
   3379     Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
   3380 
   3381     Update info about Mars time.
   3382 
   3383 
   3384 Release 2015a - 2015-01-29 22:35:20 -0800
   3385 
   3386   Changes affecting future timestamps
   3387 
   3388     The Mexican state of Quintana Roo, represented by America/Cancun,
   3389     will shift from Central Time with DST to Eastern Time without DST
   3390     on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
   3391 
   3392     Chile will not change clocks in April or thereafter; its new standard time
   3393     will be its old daylight saving time.  This affects America/Santiago,
   3394     Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
   3395 
   3396     New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
   3397     (Thanks to Tim Parenti.)
   3398 
   3399   Changes affecting past timestamps
   3400 
   3401     Iceland observed DST in 1919 and 1921, and its 1939 fallback
   3402     transition was Oct. 29, not Nov. 29.  Remove incorrect data from
   3403     Shanks about time in Iceland between 1837 and 1908.
   3404 
   3405     Some more zones have been turned into links, when they differed
   3406     from existing zones only for older timestamps.  As usual,
   3407     these changes affect UT offsets in pre-1970 timestamps only.
   3408     Their old contents have been moved to the 'backzone' file.
   3409     The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
   3410     and Asia/Muscat.
   3411 
   3412   Changes affecting code
   3413 
   3414     tzalloc now scrubs time zone abbreviations compatibly with the way
   3415     that tzset always has, by replacing invalid bytes with '_' and by
   3416     shortening too-long abbreviations.
   3417 
   3418     tzselect ports to POSIX awk implementations, no longer mishandles
   3419     POSIX TZ settings when GNU awk is used, and reports POSIX TZ
   3420     settings to the user.  (Thanks to Stefan Kuhn.)
   3421 
   3422   Changes affecting build procedure
   3423 
   3424     'make check' now checks for links to links in the data.
   3425     One such link (for Africa/Asmera) has been fixed.
   3426     (Thanks to Stephen Colebourne for pointing out the problem.)
   3427 
   3428   Changes affecting commentary
   3429 
   3430     The leapseconds file commentary now mentions the expiration date.
   3431     (Problem reported by Martin Burnicki.)
   3432 
   3433     Update Mexican Library of Congress URL.
   3434 
   3435 
   3436 Release 2014j - 2014-11-10 17:37:11 -0800
   3437 
   3438   Changes affecting current and future timestamps
   3439 
   3440     Turks & Caicos' switch from US eastern time to UT -04 year-round
   3441     did not occur on 2014-11-02 at 02:00.  It's currently scheduled
   3442     for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
   3443 
   3444   Changes affecting past timestamps
   3445 
   3446     Many pre-1989 timestamps have been corrected for Asia/Seoul and
   3447     Asia/Pyongyang, based on sources for the Korean-language Wikipedia
   3448     entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
   3449     longer guess that Pyongyang mimicked Seoul time after World War II,
   3450     as this is politically implausible.
   3451 
   3452     Some more zones have been turned into links, when they differed
   3453     from existing zones only for older timestamps.  As usual,
   3454     these changes affect UT offsets in pre-1970 timestamps only.
   3455     Their old contents have been moved to the 'backzone' file.
   3456     The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
   3457     Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
   3458     Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
   3459     Indian/Mayotte.
   3460 
   3461   Changes affecting commentary
   3462 
   3463     The commentary is less enthusiastic about Shanks as a source,
   3464     and is more careful to distinguish UT from UTC.
   3465 
   3466 
   3467 Release 2014i - 2014-10-21 22:04:57 -0700
   3468 
   3469   Changes affecting future timestamps
   3470 
   3471     Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
   3472     (Thanks to Ken Rylander for the heads-up.)  Guess that future
   3473     years will use a similar pattern.
   3474 
   3475     A new Zone Pacific/Bougainville, for the part of Papua New Guinea
   3476     that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
   3477     (Thanks to Kiley Walbom for the heads-up.)
   3478 
   3479   Changes affecting time zone abbreviations
   3480 
   3481     Since Belarus is not changing its clocks even though Moscow is,
   3482     the time zone abbreviation in Europe/Minsk is changing from FET
   3483     to its more traditional value MSK on 2014-10-26 at 01:00.
   3484     (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
   3485 
   3486     The new abbreviation IDT stands for the pre-1976 use of UT +08 in
   3487     Indochina, to distinguish it better from ICT (+07).
   3488 
   3489   Changes affecting past timestamps
   3490 
   3491     Many timestamps have been corrected for Asia/Ho_Chi_Minh before 1976
   3492     (thanks to Trn Ngc Qun for an indirect pointer to Trn Tin Bnh's
   3493     authoritative book).  Asia/Ho_Chi_Minh has been added to
   3494     zone1970.tab, to give tzselect users in Vietnam two choices,
   3495     since north and south Vietnam disagreed after our 1970 cutoff.
   3496 
   3497     Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
   3498     they differed from existing zones only for older timestamps.  As
   3499     usual, these changes affect pre-1970 timestamps only.  Their old
   3500     contents have been moved to the 'backzone' file.
   3501 
   3502   Changes affecting code
   3503 
   3504     The time-related library functions now set errno on failure, and
   3505     some crashes in the new tzalloc-related library functions have
   3506     been fixed.  (Thanks to Christos Zoulas for reporting most of
   3507     these problems and for suggesting fixes.)
   3508 
   3509     If USG_COMPAT is defined and the requested timestamp is standard time,
   3510     the tz library's localtime and mktime functions now set the extern
   3511     variable timezone to a value appropriate for that timestamp; and
   3512     similarly for ALTZONE, daylight saving time, and the altzone variable.
   3513     This change is a companion to the tzname change in 2014h, and is
   3514     designed to make timezone and altzone more compatible with tzname.
   3515 
   3516     The tz library's functions now set errno to EOVERFLOW if they fail
   3517     because the result cannot be represented.  ctime and ctime_r now
   3518     return NULL and set errno when a timestamp is out of range, rather
   3519     than having undefined behavior.
   3520 
   3521     Some bugs associated with the new 2014g functions have been fixed.
   3522     This includes a bug that largely incapacitated the new functions
   3523     time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
   3524     It also includes some uses of uninitialized variables after tzalloc.
   3525     The new code uses the standard type 'ssize_t', which the Makefile
   3526     now gives porting advice about.
   3527 
   3528   Changes affecting commentary
   3529 
   3530     Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
   3531 
   3532 
   3533 Release 2014h - 2014-09-25 18:59:03 -0700
   3534 
   3535   Changes affecting past timestamps
   3536 
   3537     America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
   3538 
   3539     Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
   3540     not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
   3541 
   3542     Some more zones have been turned into links, when they differed
   3543     from existing zones only for older timestamps.  As usual,
   3544     these changes affect UT offsets in pre-1970 timestamps only.
   3545     Their old contents have been moved to the 'backzone' file.
   3546     The affected zones are: Africa/Blantyre, Africa/Bujumbura,
   3547     Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
   3548     Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
   3549 
   3550   Changes affecting code
   3551 
   3552     zdump -V and -v now output gmtoff= values on all platforms,
   3553     not merely on platforms defining TM_GMTOFF.
   3554 
   3555     The tz library's localtime and mktime functions now set tzname to a value
   3556     appropriate for the requested timestamp, and zdump now uses this
   3557     on platforms not defining TM_ZONE, fixing a 2014g regression.
   3558     (Thanks to Tim Parenti for reporting the problem.)
   3559 
   3560     The tz library no longer sets tzname if localtime or mktime fails.
   3561 
   3562     zdump -c no longer mishandles transitions near year boundaries.
   3563     (Thanks to Tim Parenti for reporting the problem.)
   3564 
   3565     An access to uninitialized data has been fixed.
   3566     (Thanks to Jrg Richter for reporting the problem.)
   3567 
   3568     When THREAD_SAFE is defined, the code ports to the C11 memory model.
   3569     A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
   3570     and two threads race to initialize data used by gmtime-like functions.
   3571     (Thanks to Andy Heninger for reporting the problems.)
   3572 
   3573   Changes affecting build procedure
   3574 
   3575     'make check' now checks better for properly sorted data.
   3576 
   3577   Changes affecting documentation and commentary
   3578 
   3579     zdump's gmtoff=N output is now documented, and its isdst=D output
   3580     is now documented to possibly output D values other than 0 or 1.
   3581 
   3582     zdump -c's treatment of years is now documented to use the
   3583     Gregorian calendar and Universal Time without leap seconds,
   3584     and its behavior at cutoff boundaries is now documented better.
   3585     (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
   3586 
   3587     Programs are now documented to use the proleptic Gregorian calendar.
   3588     (Thanks to Alan Barrett for the suggestion.)
   3589 
   3590     Fractional-second GMT offsets have been documented for civil time
   3591     in 19th-century Chennai, Jakarta, and New York.
   3592 
   3593 
   3594 Release 2014g - 2014-08-28 12:31:23 -0700
   3595 
   3596   Changes affecting future timestamps
   3597 
   3598     Turks & Caicos is switching from US eastern time to UT -04
   3599     year-round, modeled as a switch on 2014-11-02 at 02:00.
   3600     [As noted in 2014j, this switch was later delayed.]
   3601 
   3602   Changes affecting past timestamps
   3603 
   3604     Time in Russia or the USSR before 1926 or so has been corrected by
   3605     a few seconds in the following zones: Asia/Irkutsk,
   3606     Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
   3607     Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
   3608     Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
   3609     Vladimir Karpinsky.)
   3610 
   3611     The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
   3612     This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
   3613     Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
   3614     GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
   3615     (Thanks to Stephen Colebourne for pointing to the decree.)
   3616 
   3617     Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
   3618 
   3619     A new file 'backzone' contains data which may appeal to
   3620     connoisseurs of old timestamps, although it is out of scope for
   3621     the tz database, is often poorly sourced, and contains some data
   3622     that is known to be incorrect.  The new file is not recommended
   3623     for ordinary use and its entries are not installed by default.
   3624     (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
   3625     Isle of Man entries.)
   3626 
   3627     Some more zones have been turned into links, when they differed
   3628     from existing zones only for older timestamps.  As usual,
   3629     these changes affect UT offsets in pre-1970 timestamps only.
   3630     Their old contents have been moved to the 'backzone' file.
   3631     The affected zones are: Africa/Bangui, Africa/Brazzaville,
   3632     Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
   3633     Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
   3634 
   3635   Changes affecting code
   3636 
   3637     Unless NETBSD_INSPIRED is defined to 0, the tz library now
   3638     supplies functions for creating and using objects that represent
   3639     timezones. The new functions are tzalloc, tzfree, localtime_rz,
   3640     mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
   3641     time2posix_z.  They are intended for performance: for example,
   3642     localtime_rz (unlike localtime_r) is trivially thread-safe without
   3643     locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
   3644     functions, and to Alan Barrett and Jonathan Lennox for helping to
   3645     debug the change.)
   3646 
   3647     zdump now builds with the tz library unless USE_LTZ is defined to 0,
   3648     This lets zdump use tz features even if the system library lacks them.
   3649     To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
   3650     TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
   3651 
   3652     zdump now uses localtime_rz if available, as it's significantly faster,
   3653     and it can help zdump better diagnose invalid timezone names.
   3654     Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
   3655     defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
   3656     not available, zdump now uses localtime_r and tzset if available,
   3657     as this is a bit cleaner and faster than plain localtime.  Compile
   3658     with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
   3659     lacks these two functions.
   3660 
   3661     If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
   3662     Although not needed for tz's own applications, which are single-threaded,
   3663     this supports POSIX better if the tz library is used in multithreaded apps.
   3664 
   3665     Some crashes have been fixed when zdump or the tz library is given
   3666     invalid or outlandish input.
   3667 
   3668     The tz library no longer mishandles leap seconds on platforms with
   3669     unsigned time_t in timezones that lack ordinary transitions after 1970.
   3670 
   3671     The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
   3672     already defined, to make it easier to configure on common platforms.
   3673     Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
   3674 
   3675     Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
   3676     assumes that reading uninitialized memory yields garbage values
   3677     but does not cause other problems such as traps.
   3678 
   3679     If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
   3680     more likely to guess right for ambiguous timestamps near
   3681     transitions where tm_isdst does not change.
   3682 
   3683     If HAVE_STRFTIME_L is defined to 1, the tz library now defines
   3684     strftime_l for compatibility with recent versions of POSIX.
   3685     Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
   3686     to 1 on recent POSIX versions, and to 0 otherwise.
   3687 
   3688     tzselect -c now uses a hybrid distance measure that works better
   3689     in Africa.  (Thanks to Alan Barrett for noting the problem.)
   3690 
   3691     The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
   3692     or when time_tz is defined.
   3693 
   3694     When HAVE_UTMPX_H is set the 'date' command now builds on systems
   3695     whose <utmpx.h> file does not define WTMPX_FILE, and when setting
   3696     the date it updates the wtmpx file if _PATH_WTMPX is defined.
   3697     This affects GNU/Linux and similar systems.
   3698 
   3699     For easier maintenance later, some C code has been simplified,
   3700     some lint has been removed, and the code has been tweaked so that
   3701     plain 'make' is more likely to work.
   3702 
   3703     The C type 'bool' is now used for boolean values, instead of 'int'.
   3704 
   3705     The long-obsolete LOCALE_HOME code has been removed.
   3706 
   3707     The long-obsolete 'gtime' function has been removed.
   3708 
   3709   Changes affecting build procedure
   3710 
   3711     'zdump' no longer links in ialloc.o, as it's not needed.
   3712 
   3713     'make check_time_t_alternatives' no longer assumes GNU diff.
   3714 
   3715   Changes affecting distribution tarballs
   3716 
   3717     The files checktab.awk and zoneinfo2tdf.pl are now distributed in
   3718     the tzdata tarball instead of the tzcode tarball, since they help
   3719     maintain the data.  The NEWS and Theory files are now also
   3720     distributed in the tzdata tarball, as they're relevant for data.
   3721     (Thanks to Alan Barrett for pointing this out.)  Also, the
   3722     leapseconds.awk file is no longer distributed in the tzcode
   3723     tarball, since it belongs in the tzdata tarball (where 2014f
   3724     inadvertently also distributed it).
   3725 
   3726   Changes affecting documentation and commentary
   3727 
   3728     A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
   3729     suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
   3730     for debugging it.)
   3731 
   3732     The man pages have been updated to use function prototypes,
   3733     to document thread-safe variants like localtime_r, and to document
   3734     the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
   3735     mktime_z.
   3736 
   3737     The fields in Link lines have been renamed to be more descriptive
   3738     and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
   3739     and LINK-TO has become LINK-NAME.
   3740 
   3741     tz-link.htm mentions the IETF's tzdist working group; Windows
   3742     Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
   3743 
   3744     Some broken URLs have been fixed in the commentary.  (Thanks to
   3745     Lester Caine.)
   3746 
   3747     Commentary about Philippines DST has been updated, and commentary
   3748     on pre-1970 time in India has been added.
   3749 
   3750 
   3751 Release 2014f - 2014-08-05 17:42:36 -0700
   3752 
   3753   Changes affecting future timestamps
   3754 
   3755     Russia will subtract an hour from most of its time zones on 2014-10-26
   3756     at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
   3757     There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
   3758     Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
   3759     (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
   3760     (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
   3761     (Europe/Samara) are not changing their clocks.  The changed zones are
   3762     Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
   3763     Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
   3764     Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
   3765     Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
   3766     subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
   3767     but not its UTC offset.  Two zones are added: Asia/Chita (split
   3768     from Asia/Yakutsk, and also with two hours subtracted) and
   3769     Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
   3770     subtracted).  (Thanks to Tim Parenti for much of the above.)
   3771 
   3772   Changes affecting time zone abbreviations
   3773 
   3774     Australian eastern time zone abbreviations are now AEST/AEDT not EST,
   3775     and similarly for the other Australian zones.  That is, for eastern
   3776     standard and daylight saving time the abbreviations are AEST and AEDT
   3777     instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
   3778     and AWST/AWDT are now used instead of the former CST, CWST, and WST.
   3779     This change does not affect UT offsets, only time zone abbreviations.
   3780     (Thanks to Rich Tibbett and many others.)
   3781 
   3782     Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
   3783     effective 2014-10-26 at 02:00 local time.
   3784 
   3785     The time zone abbreviation for Xinjiang Time (observed in rmqi)
   3786     has been changed from URUT to XJT.  (Thanks to Luther Ma.)
   3787 
   3788     Prefer MSK/MSD for Moscow time in Russia, even in other cities.
   3789     Similarly, prefer EET/EEST for eastern European time in Russia.
   3790 
   3791     Change time zone abbreviations in (western) Samoa to use "ST" and
   3792     "DT" suffixes, as this is more likely to match common practice.
   3793     Prefix "W" to (western) Samoa time when its standard-time offset
   3794     disagrees with that of American Samoa.
   3795 
   3796     America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
   3797 
   3798     Time zone abbreviations have been updated for Japan's two time
   3799     zones used 1896-1937.  JWST now stands for Western Standard
   3800     Time, and JCST for Central Standard Time (formerly this was CJT).
   3801     These abbreviations are now used for time in Korea, Taiwan,
   3802     and Sakhalin while controlled by Japan.
   3803 
   3804   Changes affecting past timestamps
   3805 
   3806     China's five zones have been simplified to two, since the post-1970
   3807     differences in the other three seem to have been imaginary.  The
   3808     zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
   3809     removed; backwards-compatibility links still work, albeit with
   3810     different behaviors for timestamps before May 1980.  Asia/Urumqi's
   3811     1980 transition to UT +08 has been removed, so that it is now at
   3812     +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
   3813     Treindl sent helpful translations of two papers by Guo Qingsheng.)
   3814 
   3815     Some zones have been turned into links, when they differed from existing
   3816     zones only for older UT offsets where data entries were likely invented.
   3817     These changes affect UT offsets in pre-1970 timestamps only.  This is
   3818     similar to the change in release 2013e, except this time for western
   3819     Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
   3820     Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
   3821     Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
   3822     Atlantic/St_Helena.  This also affects the backwards-compatibility
   3823     link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
   3824     Tim Parenti, and David Patte for reporting problems in earlier
   3825     versions of this change.)
   3826 
   3827     Asia/Shanghai's pre-standard-time UT offset has been changed from
   3828     8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
   3829     transition to standard time has been changed from 1928 to 1901.
   3830 
   3831     Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
   3832     then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
   3833     In 1946 it observed DST from 05-15 through 09-30; in 1947
   3834     from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
   3835     (Thanks to Yu-Cheng Chuang.)
   3836 
   3837     Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
   3838 
   3839     Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
   3840     10-03 at 00:00.  (Thanks to Konstantin Hyppnen.)
   3841 
   3842     Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
   3843     period from 1911 to 1950.
   3844 
   3845     Pacific/Chatham has been changed to New Zealand standard time plus
   3846     45 minutes for the period before 1957, reflecting a 1956 remark in
   3847     the New Zealand parliament.
   3848 
   3849     Europe/Budapest has several pre-1946 corrections: in 1918 the transition
   3850     out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
   3851     1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
   3852     not 04-06 at 02:00; and there was no DST in 1920.
   3853 
   3854     Africa/Accra is now assumed to have observed DST from 1920 through 1935.
   3855 
   3856     Time in Russia before 1927 or so has been corrected by a few seconds in
   3857     the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
   3858     Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
   3859     Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
   3860     point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
   3861 
   3862   Changes affecting data format
   3863 
   3864     A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
   3865     The new file's extended format allows multiple country codes per zone.
   3866     The older file is still installed but is deprecated; its format is
   3867     not changing and it will still be distributed for a while, but new
   3868     applications should use the new file.
   3869 
   3870     The new file format simplifies maintenance of obscure locations.
   3871     To test this, it adds coverage for the Crozet Islands and the
   3872     Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
   3873 
   3874     The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
   3875     It is still ASCII now, but commentary about the switch has been added.
   3876     The new file 'zone1970.tab' already uses UTF-8.
   3877 
   3878   Changes affecting code
   3879 
   3880     'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
   3881     is defined.  (Thanks to Elliott Hughes for reporting the problem.)
   3882 
   3883     'zic' no longer mishandles input when ignoring case in locales that
   3884     are not compatible with English, e.g., unibyte Turkish locales when
   3885     compiled with HAVE_GETTEXT.
   3886 
   3887     Error diagnostics of 'zic' and 'yearistype' have been reworded so that
   3888     they no longer use ASCII '-' as if it were a dash.
   3889 
   3890     'zic' now rejects output file names that contain '.' or '..' components.
   3891     (Thanks to Tim Parenti for reporting the problem.)
   3892 
   3893     'zic -v' now warns about output file names that do not follow
   3894     POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
   3895     David Olson for starting the ball rolling on this.)
   3896 
   3897     Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
   3898 
   3899   Changes affecting build procedure
   3900 
   3901     'zic' no longer links in localtime.o and asctime.o, as they're not needed.
   3902     (Thanks to John Cochran.)
   3903 
   3904   Changes affecting documentation and commentary
   3905 
   3906     The 'Theory' file documents legacy names, the longstanding
   3907     exceptions to the POSIX-inspired file name rules.
   3908 
   3909     The 'zic' documentation clarifies the role of time types when
   3910     interpreting dates.  (Thanks to Arthur David Olson.)
   3911 
   3912     Documentation and commentary now prefer UTF-8 to US-ASCII,
   3913     allowing the use of proper accents in foreign words and names.
   3914     Code and data have not changed because of this.  (Thanks to
   3915     Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
   3916     this.)
   3917 
   3918     Non-HTML documentation and commentary now use plain-text URLs instead of
   3919     HTML insertions, and are more consistent about bracketing URLs when they
   3920     are not already surrounded by white space.  (Thanks to suggestions by
   3921     Steffen Nurpmeso.)
   3922 
   3923     There is new commentary about Xujiahui Observatory, the five time-zone
   3924     project in China from 1918 to 1949, timekeeping in Japanese-occupied
   3925     Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
   3926     warlord Jin Shuren in the data.
   3927 
   3928     Commentary about the coverage of each Russian zone has been standardized.
   3929     (Thanks to Tim Parenti.)
   3930 
   3931     There is new commentary about contemporary timekeeping in Ethiopia.
   3932 
   3933     Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
   3934 
   3935     There is new commentary about time in Poland in 1919.
   3936 
   3937     Proper credit has been given to DST inventor George Vernon Hudson.
   3938 
   3939     Commentary about time in Metlakatla, AK and Resolute, NU has been
   3940     improved, with a new source for the former.
   3941 
   3942     In zone.tab, Pacific/Easter no longer mentions Salas y Gmez, as it
   3943     is uninhabited.
   3944 
   3945     Commentary about permanent Antarctic bases has been updated.
   3946 
   3947     Several typos have been corrected.  (Thanks to Tim Parenti for
   3948     contributing some of these fixes.)
   3949 
   3950     tz-link.htm now mentions the JavaScript libraries Moment Timezone,
   3951     TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
   3952     from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
   3953     (Thanks to a heads-up from Dirkjan Ochtman.)
   3954 
   3955     The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
   3956     have been removed.  These obsolescent US Naval Observatory entries were no
   3957     longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
   3958 
   3959 
   3960 Release 2014e - 2014-06-12 21:53:52 -0700
   3961 
   3962   Changes affecting near-future timestamps
   3963 
   3964     Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
   3965     (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
   3966     switch to standard time at 24:00 the last Thursday before Ramadan, and
   3967     back to DST at 00:00 the first Friday after Ramadan.
   3968 
   3969     Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
   3970     to Milamber Space Network.)  Guess that from 2015 on Morocco will
   3971     temporarily switch to standard time at 03:00 the last Saturday before
   3972     Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
   3973 
   3974   Changes affecting past timestamps
   3975 
   3976     The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
   3977     "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
   3978     "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
   3979     in 1991.  (Thanks to Hank W. for reporting the problems.)
   3980 
   3981   Changes affecting commentary
   3982 
   3983     tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
   3984     draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
   3985     removes stale pointers to World Time Explorer and WORLDTIME.
   3986 
   3987 
   3988 Release 2014d - 2014-05-27 21:34:40 -0700
   3989 
   3990   Changes affecting code
   3991 
   3992     zic no longer generates files containing timestamps before the Big Bang.
   3993     This works around GNOME glib bug 878
   3994     <https://gitlab.gnome.org/GNOME/glib/issues/878>
   3995     (Thanks to Leonardo Chiquitto for reporting the bug, and to
   3996     Arthur David Olson and James Cloos for suggesting improvements to the fix.)
   3997 
   3998   Changes affecting documentation
   3999 
   4000     tz-link.htm now mentions GNOME.
   4001 
   4002 
   4003 Release 2014c - 2014-05-13 07:44:13 -0700
   4004 
   4005   Changes affecting near-future timestamps
   4006 
   4007     Egypt observes DST starting 2014-05-15 at 24:00.
   4008     (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
   4009     Details have not been announced, except that DST will not be observed
   4010     during Ramadan.  Guess that DST will stop during the same Ramadan dates as
   4011     Morocco, and that Egypt's future spring and fall transitions will be the
   4012     same as 2010 when it last observed DST, namely April's last Friday at
   4013     00:00 to September's last Thursday at 23:00 standard time.  Also, guess
   4014     that Ramadan transitions will be at 00:00 standard time.
   4015 
   4016   Changes affecting code
   4017 
   4018     zic now generates transitions for minimum time values, eliminating guesswork
   4019     when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
   4020 
   4021     Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
   4022 
   4023   Changes affecting commentary and documentation
   4024 
   4025     Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
   4026 
   4027 
   4028 Release 2014b - 2014-03-24 21:28:50 -0700
   4029 
   4030   Changes affecting near-future timestamps
   4031 
   4032     Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
   4033     (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
   4034 
   4035     New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
   4036     Bengt-Inge Larsson.)  This is currently an approximation; a better version
   4037     will require the zic and localtime fixes mentioned below, and the plan is
   4038     to wait for a while until at least the zic fixes propagate.
   4039 
   4040   Changes affecting code
   4041 
   4042     'zic' and 'localtime' no longer reject locations needing four transitions
   4043     per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
   4044     Also, 'zic' avoids some unlikely failures due to integer overflow.
   4045 
   4046   Changes affecting build procedure
   4047 
   4048     'make check' now detects Rule lines defined but never used.
   4049     The NZAQ rules, an instance of this problem, have been removed.
   4050 
   4051   Changes affecting commentary and documentation
   4052 
   4053     Fix Tuesday/Thursday typo in description of time in Israel.
   4054     (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
   4055 
   4056     Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
   4057     to Donald MacQueen.)  Instead, the Microsoft Windows Store app
   4058     library supports them.
   4059 
   4060     Add comments about Johnston Island time in the 1960s.
   4061     (Thanks to Lyle McElhaney.)
   4062 
   4063     Morocco's 2014 DST start will be as predicted.
   4064     (Thanks to Sebastien Willemijns.)
   4065 
   4066 
   4067 Release 2014a - 2014-03-07 23:30:29 -0800
   4068 
   4069   Changes affecting near-future timestamps
   4070 
   4071     Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
   4072     the heads-up, and to Tim Parenti for simplifying the update.)
   4073 
   4074   Changes affecting past timestamps
   4075 
   4076     Fiji ended DST on 2014-01-19 at 02:00, not the previously scheduled 03:00.
   4077     (Thanks to Steffen Thorsen.)
   4078 
   4079     Ukraine switched from Moscow to Eastern European time on 1990-07-01
   4080     (not 1992-01-01), and observed DST during the entire next winter.
   4081     (Thanks to Vladimir in Moscow via Alois Treindl.)
   4082 
   4083     In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
   4084     (Thanks to Avigdor Finkelstein.)
   4085 
   4086   Changes affecting code
   4087 
   4088     A uninitialized-storage bug in 'localtime' has been fixed.
   4089     (Thanks to Logan Chien.)
   4090 
   4091   Changes affecting the build procedure
   4092 
   4093     The settings for 'make check_web' now default to Ubuntu 13.10.
   4094 
   4095   Changes affecting commentary and documentation
   4096 
   4097     The boundary of the US Pacific time zone is given more accurately.
   4098     (Thanks to Alan Mintz.)
   4099 
   4100     Chile's 2014 DST will be as predicted.  (Thanks to Jos Miguel Garrido.)
   4101 
   4102     Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Ral Perasso.)
   4103 
   4104     Better descriptions of countries with same time zone history as
   4105     Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
   4106 
   4107     Several changes affect tz-link.htm, the main web page.
   4108 
   4109       Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
   4110       David Braverman).
   4111 
   4112       Mention xCal (Internet RFC 6321) and jCal.
   4113 
   4114       Microsoft has some support for tz database names.
   4115 
   4116       CLDR data formats include both XML and JSON.
   4117 
   4118       Mention Maggiolo's map of solar vs standard time.
   4119       (Thanks to Arthur David Olson.)
   4120 
   4121       Mention TZ4Net.  (Thanks to Matt Johnson.)
   4122 
   4123       Mention the timezone-olson Haskell package.
   4124 
   4125       Mention zeitverschiebung.net.  (Thanks to Martin Jger.)
   4126 
   4127       Remove moribund links to daylight-savings-time.info and to
   4128       Simple Timer + Clocks.
   4129 
   4130       Update two links.  (Thanks to Oscar van Vlijmen.)
   4131 
   4132       Fix some formatting glitches, e.g., remove random newlines from
   4133       abbr elements' title attributes.
   4134 
   4135 
   4136 Release 2013i - 2013-12-17 07:25:23 -0800
   4137 
   4138   Changes affecting near-future timestamps:
   4139 
   4140     Jordan switches back to standard time at 00:00 on December 20, 2013.
   4141     The 2006-2011 transition schedule is planned to resume in 2014.
   4142     (Thanks to Steffen Thorsen.)
   4143 
   4144   Changes affecting past timestamps:
   4145 
   4146     In 2004, Cuba began DST on March 28, not April 4.
   4147     (Thanks to Steffen Thorsen.)
   4148 
   4149   Changes affecting code
   4150 
   4151     The compile-time flag NOSOLAR has been removed, as nowadays the
   4152     benefit of slightly shrinking runtime table size is outweighed by the
   4153     cost of disallowing potential future updates that exceed old limits.
   4154 
   4155   Changes affecting documentation and commentary
   4156 
   4157     The files solar87, solar88, and solar89 are no longer distributed.
   4158     They were a negative experiment - that is, a demonstration that
   4159     tz data can represent solar time only with some difficulty and error.
   4160     Their presence in the distribution caused confusion, as Riyadh
   4161     civil time was generally not solar time in those years.
   4162 
   4163     tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
   4164 
   4165 
   4166 Release 2013h - 2013-10-25 15:32:32 -0700
   4167 
   4168   Changes affecting current and future timestamps:
   4169 
   4170     Libya has switched its UT offset back to +02 without DST, instead
   4171     of +01 with DST.  (Thanks to Even Scharning.)
   4172 
   4173     Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
   4174     (Thanks to Gwillim Law.)
   4175 
   4176   Changes affecting future timestamps:
   4177 
   4178     Acre and (we guess) western Amazonas will switch from UT -04 to -05
   4179     on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
   4180     (Thanks to Steffen Thorsen.)
   4181 
   4182     Add entries for DST transitions in Morocco in the year 2038.
   4183     This avoids some year-2038 glitches introduced in 2013g.
   4184     (Thanks to Yoshito Umaoka for reporting the problem.)
   4185 
   4186   Changes affecting API
   4187 
   4188     The 'tzselect' command no longer requires the 'select' command,
   4189     and should now work with /bin/sh on more platforms.  It also works
   4190     around a bug in BusyBox awk before version 1.21.0.  (Thanks to
   4191     Patrick 'P. J.' McDermott and Alan Barrett.)
   4192 
   4193   Changes affecting code
   4194 
   4195     Fix localtime overflow bugs with 32-bit unsigned time_t.
   4196 
   4197     zdump no longer assumes sscanf returns maximal values on overflow.
   4198 
   4199   Changes affecting the build procedure
   4200 
   4201     The builder can specify which programs to use, if any, instead of
   4202     'ar' and 'ranlib', and libtz.a is now built locally before being
   4203     installed.  (Thanks to Michael Forney.)
   4204 
   4205     A dependency typo in the 'zdump' rule has been fixed.
   4206     (Thanks to Andrew Paprocki.)
   4207 
   4208     The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
   4209     work as specified by POSIX.2-1992 or later; this is portable nowadays.
   4210 
   4211     'make clean' no longer removes 'leapseconds', since it's
   4212     host-independent and is part of the distribution.
   4213 
   4214     The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
   4215 
   4216   Changes affecting documentation and commentary
   4217 
   4218     tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
   4219     (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
   4220 
   4221     Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
   4222     8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
   4223     longer maintained) and for old advisories.  SOFA now does C.
   4224 
   4225 Release 2013g - 2013-09-30 21:08:26 -0700
   4226 
   4227   Changes affecting current and near-future timestamps
   4228 
   4229     Morocco now observes DST from the last Sunday in March to the last
   4230     Sunday in October, not April to September respectively.  (Thanks
   4231     to Steffen Thorsen.)
   4232 
   4233   Changes affecting 'zic'
   4234 
   4235     'zic' now runs on platforms that lack both hard links and symlinks.
   4236     (Thanks to Theo Veenker for reporting the problem, for MinGW.)
   4237     Also, fix some bugs on platforms that lack hard links but have symlinks.
   4238 
   4239     'zic -v' again warns that Asia/Tehran has no POSIX environment variable
   4240     to predict the far future, fixing a bug introduced in 2013e.
   4241 
   4242   Changes affecting the build procedure
   4243 
   4244     The 'leapseconds' file is again put into the tzdata tarball.
   4245     Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
   4246     Matt Burgess and Ian Abbott.)  The timestamps of these and other
   4247     dependent files in tarballs are adjusted more consistently.
   4248 
   4249   Changes affecting documentation and commentary
   4250 
   4251     The README file is now part of the data tarball as well as the code.
   4252     It now states that files are public domain unless otherwise specified.
   4253     (Thanks to Andrew Main (Zefram) for asking for clarifications.)
   4254     Its details about the 1989 release moved to a place of honor near
   4255     the end of NEWS.
   4256 
   4257 
   4258 Release 2013f - 2013-09-24 23:37:36 -0700
   4259 
   4260   Changes affecting near-future timestamps
   4261 
   4262     Tocantins will very likely not observe DST starting this spring.
   4263     (Thanks to Steffen Thorsen.)
   4264 
   4265     Jordan will likely stay at UT +03 indefinitely, and will not fall
   4266     back this fall.
   4267 
   4268     Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
   4269 
   4270   Changes affecting API
   4271 
   4272     The types of the global variables 'timezone' and 'altzone' (if present)
   4273     have been changed back to 'long'.  This is required for 'timezone'
   4274     by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
   4275     These variables were originally 'long' in the tz code, but were
   4276     mistakenly changed to 'time_t' in 1987; nobody reported the
   4277     incompatibility until now.  The difference matters on x32, where
   4278     'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
   4279 
   4280   Changes affecting the build procedure
   4281 
   4282     Avoid long strings in leapseconds.awk to work around a mawk bug.
   4283     (Thanks to Cyril Baurand.)
   4284 
   4285   Changes affecting documentation and commentary
   4286 
   4287     New file 'NEWS' that contains release notes like this one.
   4288 
   4289     Paraguay's law does not specify DST transition time; 00:00 is customary.
   4290     (Thanks to Waldemar Villamayor-Venialbo.)
   4291 
   4292     Minor capitalization fixes.
   4293 
   4294   Changes affecting version-control only
   4295 
   4296     The experimental GitHub repository now contains annotated and
   4297     signed tags for recent releases, e.g., '2013e' for Release 2013e.
   4298     Releases are tagged starting with 2012e; earlier releases were
   4299     done differently, and tags would either not have a simple name or
   4300     not exactly match what was released.
   4301 
   4302     'make set-timestamps' is now simpler and a bit more portable.
   4303 
   4304 
   4305 Release 2013e - 2013-09-19 23:50:04 -0700
   4306 
   4307   Changes affecting near-future timestamps
   4308 
   4309     This year Fiji will start DST on October 27, not October 20.
   4310     (Thanks to David Wheeler for the heads-up.)  For now, guess that
   4311     Fiji will continue to spring forward the Sunday before the fourth
   4312     Monday in October.
   4313 
   4314   Changes affecting current and future time zone abbreviations
   4315 
   4316     Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
   4317     time zone abbreviations since 1932.  (Thanks to George Ziegler,
   4318     Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
   4319     Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
   4320     Asia/Makassar, and Asia/Pontianak.
   4321 
   4322     Use ART (UT -03, standard time), rather than WARST (also -03, but
   4323     daylight saving time) for San Luis, Argentina since 2009.
   4324 
   4325   Changes affecting Godthb timestamps after 2037 if version mismatch
   4326 
   4327     Allow POSIX-like TZ strings where the transition time's hour can
   4328     range from -167 through 167, instead of the POSIX-required 0
   4329     through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
   4330     new Fiji rules.  This is a more compact way to represent
   4331     far-future timestamps for America/Godthab, America/Santiago,
   4332     Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
   4333     Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
   4334     this change.  (Derived from a suggestion by Arthur David Olson.)
   4335 
   4336     Allow POSIX-like TZ strings where daylight saving time is in
   4337     effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
   4338     Argentina Summer Time all year.  This supports a more compact way
   4339     to represent the 2013d data for America/Argentina/San_Luis.
   4340     Because of the change for San Luis noted above this change does not
   4341     affect the current data.  (Thanks to Andrew Main (Zefram) for
   4342     suggestions that improved this change.)
   4343 
   4344     Where these two TZ changes take effect, there is a minor extension
   4345     to the tz file format in that it allows new values for the
   4346     embedded TZ-format string, and the tz file format version number
   4347     has therefore been increased from 2 to 3 as a precaution.
   4348     Version-2-based client code should continue to work as before for
   4349     all timestamps before 2038.  Existing version-2-based client code
   4350     (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
   4351     files, and typically works in practice even for timestamps after
   4352     2037; the only known exception is America/Godthab.
   4353 
   4354   Changes affecting timestamps before 1970
   4355 
   4356     Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
   4357     some errors before 1947.
   4358 
   4359     Some zones have been turned into links, when they differ from existing
   4360     zones only in older data entries that were likely invented or that
   4361     differ only in LMT or transitions from LMT.  These changes affect
   4362     only timestamps before 1943.  The affected zones are:
   4363     Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
   4364     America/Grenada, America/Guadeloupe, America/Marigot,
   4365     America/Montserrat, America/St_Barthelemy, America/St_Kitts,
   4366     America/St_Lucia, America/St_Thomas, America/St_Vincent,
   4367     America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
   4368     confirming that the old Europe/Vaduz zone was wrong and the new
   4369     link is better for WWII-era times.)
   4370 
   4371     Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
   4372     America/Cayman, America/Jamaica and America/Grand_Turk timestamps
   4373     from 1890 to 1912.
   4374 
   4375     Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
   4376     This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
   4377     to Alois Treindl.)
   4378 
   4379     Change the date of the circa-1850 Zurich transition from 1849-09-12
   4380     to 1853-07-16, overriding Shanks with data from Messerli about
   4381     postal and telegraph time in Switzerland.
   4382 
   4383   Changes affecting time zone abbreviations before 1970
   4384 
   4385     For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
   4386     as Jakarta was called Batavia back then.
   4387 
   4388   Changes affecting API
   4389 
   4390     The 'zic' command now outputs a dummy transition when far-future
   4391     data can't be summarized using a TZ string, and uses a 402-year
   4392     window rather than a 400-year window.  For the current data, this
   4393     affects only the Asia/Tehran file.  It does not affect any of the
   4394     timestamps that this file represents, so zdump outputs the same
   4395     information as before.  (Thanks to Andrew Main (Zefram).)
   4396 
   4397     The 'date' command has a new '-r' option, which lets you specify
   4398     the integer time to display, a la FreeBSD.
   4399 
   4400     The 'tzselect' command has two new options '-c' and '-n', which lets you
   4401     select a zone based on latitude and longitude.
   4402 
   4403     The 'zic' command's '-v' option now warns about constructs that
   4404     require the new version-3 binary file format.  (Thanks to Arthur
   4405     David Olson for the suggestion.)
   4406 
   4407     Support for floating-point time_t has been removed.
   4408     It was always dicey, and POSIX no longer requires it.
   4409     (Thanks to Eric Blake for suggesting to the POSIX committee to
   4410     remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
   4411     Heninger, Arthur David Olson, and Alois Treindl, for reporting
   4412     bugs and elucidating some of the corners of the old floating-point
   4413     implementation.)
   4414 
   4415     The signatures of 'offtime', 'timeoff', and 'gtime' have been
   4416     changed back to the old practice of using 'long' to represent UT
   4417     offsets.  This had been inadvertently and mistakenly changed to
   4418     'int_fast32_t'.  (Thanks to Christos Zoulas.)
   4419 
   4420     The code avoids undefined behavior on integer overflow in some
   4421     more places, including gmtime, localtime, mktime and zdump.
   4422 
   4423   Changes affecting the zdump utility
   4424 
   4425     zdump now outputs "UT" when referring to Universal Time, not "UTC".
   4426     "UTC" does not make sense for timestamps that predate the introduction
   4427     of UTC, whereas "UT", a more generic term, does.  (Thanks to Steve Allen
   4428     for clarifying UT vs UTC.)
   4429 
   4430   Data changes affecting behavior of tzselect and similar programs
   4431 
   4432     Country code BQ is now called the more common name "Caribbean Netherlands"
   4433     rather than the more official "Bonaire, St Eustatius & Saba".
   4434 
   4435     Remove from zone.tab the names America/Montreal, America/Shiprock,
   4436     and Antarctica/South_Pole, as they are equivalent to existing
   4437     same-country-code zones for post-1970 timestamps.  The data entries for
   4438     these names are unchanged, so the names continue to work as before.
   4439 
   4440   Changes affecting code internals
   4441 
   4442     zic -c now runs way faster on 64-bit hosts when given large numbers.
   4443 
   4444     zic now uses vfprintf to avoid allocating and freeing some memory.
   4445 
   4446     tzselect now computes the list of continents from the data,
   4447     rather than have it hard-coded.
   4448 
   4449     Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
   4450 
   4451   Changes affecting the build procedure
   4452 
   4453     The 'leapseconds' file is now generated automatically from a
   4454     new file 'leap-seconds.list', which is a copy of
   4455     <ftp://ftp.nist.gov/pub/time/leap-seconds.list>
   4456     A new source file 'leapseconds.awk' implements this.
   4457     The goal is simplification of the future maintenance of 'leapseconds'.
   4458 
   4459     When building the 'posix' or 'right' subdirectories, if the
   4460     subdirectory would be a copy of the default subdirectory, it is
   4461     now made a symbolic link if that is supported.  This saves about
   4462     2 MB of file system space.
   4463 
   4464     The links America/Shiprock and Antarctica/South_Pole have been
   4465     moved to the 'backward' file.  This affects only nondefault builds
   4466     that omit 'backward'.
   4467 
   4468   Changes affecting version-control only
   4469 
   4470     .gitignore now ignores 'date'.
   4471 
   4472   Changes affecting documentation and commentary
   4473 
   4474     Changes to the 'tzfile' man page
   4475 
   4476       It now mentions that the binary file format may be extended in
   4477       future versions by appending data.
   4478 
   4479       It now refers to the 'zdump' and 'zic' man pages.
   4480 
   4481     Changes to the 'zic' man page
   4482 
   4483       It lists conditions that elicit a warning with '-v'.
   4484 
   4485       It says that the behavior is unspecified when duplicate names
   4486       are given, or if the source of one link is the target of another.
   4487 
   4488       Its examples are updated to match the latest data.
   4489 
   4490       The definition of white space has been clarified slightly.
   4491       (Thanks to Michael Deckers.)
   4492 
   4493     Changes to the 'Theory' file
   4494 
   4495       There is a new section about the accuracy of the tz database,
   4496       describing the many ways that errors can creep in, and
   4497       explaining why so many of the pre-1970 timestamps are wrong or
   4498       misleading (thanks to Steve Allen, Lester Caine, and Garrett
   4499       Wollman for discussions that contributed to this).
   4500 
   4501       The 'Theory' file describes LMT better (this follows a
   4502       suggestion by Guy Harris).
   4503 
   4504       It refers to the 2013 edition of POSIX rather than the 2004 edition.
   4505 
   4506       It's mentioned that excluding 'backward' should not affect the
   4507       other data, and it suggests at least one zone.tab name per
   4508       inhabited country (thanks to Stephen Colebourne).
   4509 
   4510       Some longstanding restrictions on names are documented, e.g.,
   4511       'America/New_York' precludes 'America/New_York/Bronx'.
   4512 
   4513       It gives more reasons for the 1970 cutoff.
   4514 
   4515       It now mentions which time_t variants are supported, such as
   4516       signed integer time_t.  (Thanks to Paul Goyette for reporting
   4517       typos in an experimental version of this change.)
   4518 
   4519       (Thanks to Philip Newton for correcting typos in these changes.)
   4520 
   4521     Documentation and commentary is more careful to distinguish UT in
   4522     general from UTC in particular.  (Thanks to Steve Allen.)
   4523 
   4524     Add a better source for the Zurich 1894 transition.
   4525     (Thanks to Pierre-Yves Berger.)
   4526 
   4527     Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
   4528 
   4529 
   4530 Release 2013d - 2013-07-05 07:38:01 -0700
   4531 
   4532   Changes affecting future timestamps:
   4533 
   4534     Morocco's midsummer transitions this year are July 7 and August 10,
   4535     not July 9 and August 8.  (Thanks to Andrew Paprocki.)
   4536 
   4537     Israel now falls back on the last Sunday of October.
   4538     (Thanks to Ephraim Silverberg.)
   4539 
   4540   Changes affecting past timestamps:
   4541 
   4542     Specify Jerusalem's location more precisely; this changes the pre-1880
   4543     times by 2 s.
   4544 
   4545   Changing affecting metadata only:
   4546 
   4547     Fix typos in the entries for country codes BQ and SX.
   4548 
   4549   Changes affecting code:
   4550 
   4551     Rework the code to fix a bug with handling Australia/Macquarie on
   4552     32-bit hosts (thanks to Arthur David Olson).
   4553 
   4554     Port to platforms like NetBSD, where time_t can be wider than long.
   4555 
   4556     Add support for testing time_t types other than the system's.
   4557     Run 'make check_time_t_alternatives' to try this out.
   4558     Currently, the tests fail for unsigned time_t;
   4559     this should get fixed at some point.
   4560 
   4561   Changes affecting documentation and commentary:
   4562 
   4563     Deemphasize the significance of national borders.
   4564 
   4565     Update the zdump man page.
   4566 
   4567     Remove obsolete NOID comment (thanks to Denis Excoffier).
   4568 
   4569     Update several URLs and comments in the web pages.
   4570 
   4571     Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
   4572 
   4573     Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
   4574 
   4575 
   4576 Release 2013c - 2013-04-19 16:17:40 -0700
   4577 
   4578   Changes affecting current and future timestamps:
   4579 
   4580     Palestine observed DST starting March 29, 2013.  (Thanks to
   4581     Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
   4582     with the predicted rules being the last Thursday in March at 24:00
   4583     to the first Friday on or after September 21 at 01:00.
   4584 
   4585     Assume that the recent change to Paraguay's DST rules is permanent,
   4586     by moving the end of DST to the 4th Sunday in March every year.
   4587     (Thanks to Carlos Ral Perasso.)
   4588 
   4589   Changes affecting past timestamps:
   4590 
   4591     Fix some historical data for Palestine to agree with that of
   4592     timeanddate.com, as follows:
   4593 
   4594 	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
   4595 	  00:00 Apr 1.
   4596 
   4597 	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
   4598 	  02:00.
   4599 
   4600 	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
   4601 
   4602 	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
   4603 
   4604 	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
   4605 
   4606 	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
   4607 
   4608     Fix times of habitation for Macquarie to agree with the Tasmania
   4609     Parks & Wildlife Service history, which indicates that permanent
   4610     habitation was 1899-1919 and 1948 on.
   4611 
   4612   Changing affecting metadata only:
   4613 
   4614     Macquarie Island is politically part of Australia, not Antarctica.
   4615     (Thanks to Tobias Conradi.)
   4616 
   4617     Sort Macquarie more consistently with other parts of Australia.
   4618     (Thanks to Tim Parenti.)
   4619 
   4620 
   4621 Release 2013b - 2013-03-10 22:33:40 -0700
   4622 
   4623   Changes affecting current and future timestamps:
   4624 
   4625     Haiti uses US daylight-saving rules this year, and presumably future years.
   4626     This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
   4627 
   4628     Paraguay will end DST on March 24 this year.
   4629     (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
   4630 
   4631     Morocco does not observe DST during Ramadan;
   4632     try to predict Ramadan in Morocco as best we can.
   4633     (Thanks to Erik Homoet for the heads-up.)
   4634 
   4635   Changes affecting commentary:
   4636 
   4637     Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
   4638     Update URL for Solaris.  Mention Internet RFC 6557.
   4639     Update Internet RFCs 2445->5545, 2822->5322.
   4640     Switch from FTP to HTTP for Internet RFCs.
   4641 
   4642 
   4643 Release 2013a - 2013-02-27 09:20:35 -0800
   4644 
   4645   Change affecting binary data format:
   4646 
   4647     The zone offset at the end of version-2-format zone files is now
   4648     allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
   4649 
   4650   Changes affecting current and future timestamps:
   4651 
   4652     Chile's 2013 rules, and we guess rules for 2014 and later, will be
   4653     the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
   4654     (Thanks to Steffen Thorsen and Robert Elz.)
   4655 
   4656     New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
   4657     (Thanks to Tobias Conradi and Arthur David Olson.)
   4658 
   4659   Many changes affect historical timestamps before 1940.
   4660   These were deduced from: Milne J. Civil time. Geogr J. 1899
   4661   Feb;13(2):173-94 <https://www.jstor.org/stable/1774359>.
   4662 
   4663   Changes affecting the code:
   4664 
   4665     Fix zic bug that mishandled Egypt's 2010 changes (this also affected
   4666     the data).  (Thanks to Arthur David Olson.)
   4667 
   4668     Fix localtime bug when time_t is unsigned and data files were generated
   4669     by a signed time_t system.  (Thanks to Doug Bailey for reporting and
   4670     to Arthur David Olson for fixing.)
   4671 
   4672     Allow the email address for bug reports to be set by the packager.
   4673     The default is tz (a] iana.org, as before.  (Thanks to Joseph S. Myers.)
   4674 
   4675     Update HTML checking to be compatible with Ubuntu 12.10.
   4676 
   4677     Check that files are a safe subset of ASCII.  At some point we may
   4678     relax this requirement to a safe subset of UTF-8.  Without the
   4679     check, some non-UTF-8 encodings were leaking into the distribution.
   4680 
   4681   Commentary changes:
   4682 
   4683     Restore a comment about copyright notices that was inadvertently deleted.
   4684     (Thanks to Arthur David Olson.)
   4685 
   4686     Improve the commentary about which districts observe what times
   4687     in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
   4688 
   4689     Add web page links to tz.js.
   4690 
   4691     Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
   4692 
   4693 
   4694 Release 2012j - 2012-11-12 18:34:49 -0800
   4695 
   4696   Libya moved to CET this weekend, but with DST planned next year.
   4697   (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
   4698 
   4699   Signatures now have the extension .asc, not .sign, as that's more
   4700   standard.  (Thanks to Phil Pennock.)
   4701 
   4702   The output of 'zdump --version', and of 'zic --version', now
   4703   uses a format that is more typical for --version.
   4704   (Thanks to Joseph S. Myers.)
   4705 
   4706   The output of 'tzselect --help', 'zdump --help', and 'zic --help'
   4707   now uses tz (a] iana.org rather than the old elsie address.
   4708 
   4709   zic -v now complains about abbreviations that are less than 3
   4710   or more than 6 characters, as per POSIX.  Formerly, it checked
   4711   for abbreviations that were more than 3.
   4712 
   4713   'make public' no longer puts its temporary directory under /tmp,
   4714   and uses the just-built zic rather than the system zic.
   4715 
   4716   Various fixes to documentation and commentary.
   4717 
   4718 
   4719 Release 2012i - 2012-11-03 12:57:09 -0700
   4720 
   4721   Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
   4722 
   4723   Linker flags can now be specified via LDFLAGS.
   4724   AWK now defaults to 'awk', not 'nawk'.
   4725   The shell in tzselect now defaults to /bin/bash, but this can
   4726   be overridden by specifying KSHELL.
   4727   The main web page now mentions the unofficial GitHub repository.
   4728   (Thanks to Mike Frysinger.)
   4729 
   4730   Tarball signatures can now be built by running 'make signatures'.
   4731   There are also new makefile rules 'tarballs', 'check_public', and
   4732   separate makefile rules for each tarball and signature file.
   4733   A few makefile rules are now more portable to strict POSIX.
   4734 
   4735   The main web page now lists the canonical IANA URL.
   4736 
   4737 
   4738 Release 2012h - 2012-10-26 22:49:10 -0700
   4739 
   4740   Bahia no longer has DST.  (Thanks to Kelley Cook.)
   4741 
   4742   Tocantins has DST.  (Thanks to Rodrigo Severo.)
   4743 
   4744   Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
   4745 
   4746   Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
   4747 
   4748   Web page updates.
   4749 
   4750   More C modernization, except that at Arthur David Olson's suggestion
   4751   the instances of 'register' were kept.
   4752 
   4753 
   4754 Release 2012g - 2012-10-17 20:59:45 -0700
   4755 
   4756   Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
   4757 
   4758   Palestine fall 2012.  (Thanks to Steffen Thorsen.)
   4759 
   4760   Assume C89.
   4761 
   4762   To attack the version-number problem, this release ships the file
   4763   'Makefile' (which contains the release number) in both the tzcode and
   4764   the tzdata tarballs.  The two Makefiles are identical, and should be
   4765   identical in any matching pair of tarballs, so it shouldn't matter
   4766   which order you extract the tarballs.  Perhaps we can come up with a
   4767   better version-number scheme at some point; this scheme does have the
   4768   virtue of not adding more files.
   4769 
   4770 
   4771 Release 2012f - 2012-09-12 23:17:03 -0700
   4772 
   4773   * australasia (Pacific/Fiji): Fiji DST is October 21 through January
   4774     20 this year.  (Thanks to Steffen Thorsen.)
   4775 
   4776 
   4777 Release 2012e - 2012-08-02 20:44:55 -0700
   4778 
   4779   * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
   4780     (Thanks to Steffen Thorsen.)
   4781 
   4782   * Use a single version number for both code and data.
   4783 
   4784   * .gitignore: New file.
   4785 
   4786   * Remove trailing white space.
   4787 
   4788 
   4789 Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
   4790 
   4791   Changes for Morocco's timestamps, which take effect in a couple of
   4792   hours, along with infrastructure changes to accommodate how the tz
   4793   code and data are released on IANA.
   4794 
   4795 
   4796 Release data2012c - 2012-03-27 12:17:25 -0400
   4797 
   4798   africa
   4799 	Summer time changes for Morocco (to start late April 2012)
   4800 
   4801   asia
   4802 	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
   4803 
   4804   northamerica
   4805 	Haiti following US/Canada rules for 2012 (and we're assuming,
   4806 	for now anyway, for the future).
   4807 
   4808 
   4809 Release 2012b - 2012-03-02 12:29:15 +0700
   4810 
   4811   There is just one change to tzcode2012b (compared with 2012a):
   4812   the Makefile that was accidentally included with 2012a has been
   4813   replaced with the version that should have been there, which is
   4814   identical with the previous version (from tzcode2011i).
   4815 
   4816   There are just two changes in tzdata2012b compared with 2012a.
   4817 
   4818   Most significantly, summer time in Cuba has been delayed 3 weeks
   4819   (now starts April 1 rather than March 11).   Since Mar 11 (the old start
   4820   date, as listed in 2012a) is just a little over a week away, this
   4821   change is urgent.
   4822 
   4823   Less importantly, an excess tab in one of the changes in zone.tab
   4824   in 2012a has been removed.
   4825 
   4826 
   4827 Release 2012a - 2012-03-01 18:28:10 +0700
   4828 
   4829   The changes in tzcode2012a (compared to the previous version, 2011i)
   4830   are entirely to the README and tz-art.htm and tz-link.htm files, if
   4831   none of those concern you, you can ignore the code update.  The changes
   4832   reflect the changed addresses for the mailing list and the code and
   4833   data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
   4834   has been added to tz-link.htm).
   4835 
   4836   In tzdata2012a (compared to the previous release, which was 2011n)
   4837   the major changes are:
   4838 	Chile 2011/2012 and 2012/2013 summer time date adjustments.
   4839 	Falkland Islands onto permanent summer time (we're assuming for the
   4840 		foreseeable future, though 2012 is all we're fairly certain of.)
   4841 	Armenia has abolished Summer Time.
   4842 	Tokelau jumped the International Date Line back last December
   4843 		(just the same as their near neighbour, Samoa).
   4844 	America/Creston is a new zone for a small area of British Columbia
   4845 	There will be a leapsecond 2012-06-30 23:59:60 UTC.
   4846 
   4847   Other minor changes are:
   4848 	Corrections to 1918 Canadian summer time end dates.
   4849 	Updated URL for UK time zone history (in comments)
   4850 	A few typos in Le Corre's list of free French place names (comments)
   4851 
   4852 
   4853 Release data2011n - 2011-10-30 14:57:54 +0700
   4854 
   4855   There are three changes of note - most urgently, Cuba (America/Havana)
   4856   has extended summer time by two weeks, now to end on Nov 13, rather than
   4857   the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
   4858   (Europe/Tiraspol) decided not to split from the rest of Moldova after
   4859   all, and consequently that zone has been removed (again) and reinstated
   4860   in the "backward" file as a link to Europe/Chisinau.   And third, the
   4861   end date for Fiji's summer time this summer was moved forward from the
   4862   earlier planned Feb 26, to Jan 22.
   4863 
   4864   Apart from that, Moldova (MD) returns to a single entry in zone.tab
   4865   (and the incorrect syntax that was in the 2011m version of that file
   4866   is so fixed - it would have been fixed in a different way had this
   4867   change not happened - that's the "missing" sccs version id).
   4868 
   4869 
   4870 Release data2011m - 2011-10-24 21:42:16 +0700
   4871 
   4872   In particular, the typos in comments in the data (2011-11-17 should have
   4873   been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
   4874   Tim Parenti noted) have been fixed, and the change for Ukraine has been
   4875   made in all 4 Ukrainian zones, rather than just Europe/Kiev
   4876   (again, thanks to Tim Parenti, and also Denys Gavrysh).
   4877 
   4878   In addition, I added Europe/Tiraspol to zone.tab.
   4879 
   4880   This time, all the files have new version numbers...  (including the files
   4881   otherwise unchanged in 2011m that were changed in 2011l but didn't get new
   4882   version numbers there...)
   4883 
   4884 
   4885 Release data2011l - 2011-10-10 11:15:43 +0700
   4886 
   4887   There are just 2 changes that cause different generated tzdata files from
   4888   zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
   4889   is included, but commented out.  Compared with the diff I sent out last week,
   4890   this version also includes attributions for the sources for the changes
   4891   (in much the same format as ado used, but the html tags have not been
   4892   checked, verified, or used in any way at all, so if there are errors there,
   4893   please let me know.)
   4894 
   4895 
   4896 Release data2011k - 2011-09-20 17:54:03 -0400
   4897 
   4898   [not summarized]
   4899 
   4900 
   4901 Release data2011j - 2011-09-12 09:22:49 -0400
   4902 
   4903   (contemporary changes for Samoa; past changes for Kenya, Uganda, and
   4904   Tanzania); there are also two spelling corrections to comments in
   4905   the australasia file (with thanks to Christos Zoulas).
   4906 
   4907 
   4908 Release 2011i - 2011-08-29 05:56:32 -0400
   4909 
   4910   [not summarized]
   4911 
   4912 
   4913 Release data2011h - 2011-06-15 18:41:48 -0400
   4914 
   4915   Russia and Curaao changes
   4916 
   4917 
   4918 Release 2011g - 2011-04-25 09:07:22 -0400
   4919 
   4920   update the rules for Egypt to reflect its abandonment of DST this year
   4921 
   4922 
   4923 Release 2011f - 2011-04-06 17:14:53 -0400
   4924 
   4925   [not summarized]
   4926 
   4927 
   4928 Release 2011e - 2011-03-31 16:04:38 -0400
   4929 
   4930   Morocco, Chile, and tz-link changes
   4931 
   4932 
   4933 Release 2011d - 2011-03-14 09:18:01 -0400
   4934 
   4935   changes that impact present-day timestamps in Cuba, Samoa, and Turkey
   4936 
   4937 
   4938 Release 2011c - 2011-03-07 09:30:09 -0500
   4939 
   4940   These do affect current timestamps in Chile and Annette Island, Canada.
   4941 
   4942 
   4943 Release 2011b - 2011-02-07 08:44:50 -0500
   4944 
   4945   [not summarized]
   4946 
   4947 
   4948 Release 2011a - 2011-01-24 10:30:16 -0500
   4949 
   4950   [not summarized]
   4951 
   4952 
   4953 Release data2010o - 2010-11-01 09:18:23 -0400
   4954 
   4955   change to the end of DST in Fiji in 2011
   4956 
   4957 
   4958 Release 2010n - 2010-10-25 08:19:17 -0400
   4959 
   4960   [not summarized]
   4961 
   4962 
   4963 Release 2010m - 2010-09-27 09:24:48 -0400
   4964 
   4965   Hong Kong, Vostok, and zic.c changes
   4966 
   4967 
   4968 Release 2010l - 2010-08-16 06:57:25 -0400
   4969 
   4970   [not summarized]
   4971 
   4972 
   4973 Release 2010k - 2010-07-26 10:42:27 -0400
   4974 
   4975   [not summarized]
   4976 
   4977 
   4978 Release 2010j - 2010-05-10 09:07:48 -0400
   4979 
   4980   changes for Baha de Banderas and for version naming
   4981 
   4982 
   4983 Release data2010i - 2010-04-16 18:50:45 -0400
   4984 
   4985   the end of DST in Morocco on 2010-08-08
   4986 
   4987 
   4988 Release data2010h - 2010-04-05 09:58:56 -0400
   4989 
   4990   [not summarized]
   4991 
   4992 
   4993 Release data2010g - 2010-03-24 11:14:53 -0400
   4994 
   4995   [not summarized]
   4996 
   4997 
   4998 Release 2010f - 2010-03-22 09:45:46 -0400
   4999 
   5000   [not summarized]
   5001 
   5002 
   5003 Release data2010e - 2010-03-08 14:24:27 -0500
   5004 
   5005   corrects the Dhaka bug found by Danvin Ruangchan
   5006 
   5007 
   5008 Release data2010d - 2010-03-06 07:26:01 -0500
   5009 
   5010   [not summarized]
   5011 
   5012 
   5013 Release 2010c - 2010-03-01 09:20:58 -0500
   5014 
   5015   changes including KRE's suggestion for earlier initialization of
   5016   "goahead" and "goback" structure elements
   5017 
   5018 
   5019 Release code2010a - 2010-02-16 10:40:04 -0500
   5020 
   5021   [not summarized]
   5022 
   5023 
   5024 Release data2010b - 2010-01-20 12:37:01 -0500
   5025 
   5026   Mexico changes
   5027 
   5028 
   5029 Release data2010a - 2010-01-18 08:30:04 -0500
   5030 
   5031   changes to Dhaka
   5032 
   5033 
   5034 Release data2009u - 2009-12-26 08:32:28 -0500
   5035 
   5036   changes to DST in Bangladesh
   5037 
   5038 
   5039 Release 2009t - 2009-12-21 13:24:27 -0500
   5040 
   5041   [not summarized]
   5042 
   5043 
   5044 Release data2009s - 2009-11-14 10:26:32 -0500
   5045 
   5046   (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
   5047 
   5048 
   5049 Release 2009r - 2009-11-09 10:10:31 -0500
   5050 
   5051   "antarctica" and "tz-link.htm" changes
   5052 
   5053 
   5054 Release 2009q - 2009-11-02 09:12:40 -0500
   5055 
   5056   with two corrections as reported by Eric Muller and Philip Newton
   5057 
   5058 
   5059 Release data2009p - 2009-10-23 15:05:27 -0400
   5060 
   5061   Argentina (including San Luis) changes (with the correction from
   5062   Mariano Absatz)
   5063 
   5064 
   5065 Release data2009o - 2009-10-14 16:49:38 -0400
   5066 
   5067   Samoa (commentary only), Pakistan, and Bangladesh changes
   5068 
   5069 
   5070 Release data2009n - 2009-09-22 15:13:38 -0400
   5071 
   5072   added commentary for Argentina and a change to the end of DST in
   5073   2009 in Pakistan
   5074 
   5075 
   5076 Release data2009m - 2009-09-03 10:23:43 -0400
   5077 
   5078   Samoa and Palestine changes
   5079 
   5080 
   5081 Release data2009l - 2009-08-14 09:13:07 -0400
   5082 
   5083   Samoa (comments only) and Egypt
   5084 
   5085 
   5086 Release 2009k - 2009-07-20 09:46:08 -0400
   5087 
   5088   [not summarized]
   5089 
   5090 
   5091 Release data2009j - 2009-06-15 06:43:59 -0400
   5092 
   5093   Bangladesh change (with a short turnaround since the DST change is
   5094   impending)
   5095 
   5096 
   5097 Release 2009i - 2009-06-08 09:21:22 -0400
   5098 
   5099   updating for DST in Bangladesh this year
   5100 
   5101 
   5102 Release 2009h - 2009-05-26 09:19:14 -0400
   5103 
   5104   [not summarized]
   5105 
   5106 
   5107 Release data2009g - 2009-04-20 16:34:07 -0400
   5108 
   5109   Cairo
   5110 
   5111 
   5112 Release data2009f - 2009-04-10 11:00:52 -0400
   5113 
   5114   correct DST in Pakistan
   5115 
   5116 
   5117 Release 2009e - 2009-04-06 09:08:11 -0400
   5118 
   5119   [not summarized]
   5120 
   5121 
   5122 Release 2009d - 2009-03-23 09:38:12 -0400
   5123 
   5124   Morocco, Tunisia, Argentina, and American Astronomical Society changes
   5125 
   5126 
   5127 Release data2009c - 2009-03-16 09:47:51 -0400
   5128 
   5129   change to the start of Cuban DST
   5130 
   5131 
   5132 Release 2009b - 2009-02-09 11:15:22 -0500
   5133 
   5134   [not summarized]
   5135 
   5136 
   5137 Release 2009a - 2009-01-21 10:09:39 -0500
   5138 
   5139   [not summarized]
   5140 
   5141 
   5142 Release data2008i - 2008-10-21 12:10:25 -0400
   5143 
   5144   southamerica and zone.tab files, with Argentina DST rule changes and
   5145   United States zone reordering and recommenting
   5146 
   5147 
   5148 Release 2008h - 2008-10-13 07:33:56 -0400
   5149 
   5150   [not summarized]
   5151 
   5152 
   5153 Release 2008g - 2008-10-06 09:03:18 -0400
   5154 
   5155   Fix a broken HTML anchor and update Brazil's DST transitions;
   5156   there's also a slight reordering of information in tz-art.htm.
   5157 
   5158 
   5159 Release data2008f - 2008-09-09 22:33:26 -0400
   5160 
   5161   [not summarized]
   5162 
   5163 
   5164 Release 2008e - 2008-07-28 14:11:17 -0400
   5165 
   5166   changes by Arthur David Olson and Jesper Nrgaard Welen
   5167 
   5168 
   5169 Release data2008d - 2008-07-07 09:51:38 -0400
   5170 
   5171   changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
   5172 
   5173 
   5174 Release data2008c - 2008-05-19 17:48:03 -0400
   5175 
   5176   Pakistan, Morocco, and Mongolia
   5177 
   5178 
   5179 Release data2008b - 2008-03-24 08:30:59 -0400
   5180 
   5181   including renaming Asia/Calcutta to Asia/Kolkata, with a backward
   5182   link provided
   5183 
   5184 
   5185 Release 2008a - 2008-03-08 05:42:16 -0500
   5186 
   5187   [not summarized]
   5188 
   5189 
   5190 Release 2007k - 2007-12-31 10:25:22 -0500
   5191 
   5192   most importantly, changes to the "southamerica" file based on
   5193   Argentina's readoption of daylight saving time
   5194 
   5195 
   5196 Release 2007j - 2007-12-03 09:51:01 -0500
   5197 
   5198   1. eliminate the "P" (parameter) macro;
   5199 
   5200   2. the "noncontroversial" changes circulated on the time zone
   5201   mailing list (less the changes to "logwtmp.c");
   5202 
   5203   3. eliminate "too many transition" errors when "min" is used in time
   5204   zone rules;
   5205 
   5206   4. changes by Paul Eggert (including updated information for Venezuela).
   5207 
   5208 
   5209 Release data2007i - 2007-10-30 10:28:11 -0400
   5210 
   5211   changes for Cuba and Syria
   5212 
   5213 
   5214 Release 2007h - 2007-10-01 10:05:51 -0400
   5215 
   5216   changes by Paul Eggert, as well as an updated link to the ICU
   5217   project in tz-link.htm
   5218 
   5219 
   5220 Release 2007g - 2007-08-20 10:47:59 -0400
   5221 
   5222   changes by Paul Eggert
   5223 
   5224   The "leapseconds" file has been updated to incorporate the most
   5225   recent International Earth Rotation and Reference Systems Service
   5226   (IERS) bulletin.
   5227 
   5228   There's an addition to tz-art.htm regarding the television show "Medium".
   5229 
   5230 
   5231 Release 2007f - 2007-05-07 10:46:46 -0400
   5232 
   5233   changes by Paul Eggert (including Haiti, Turks and Caicos, and New
   5234   Zealand)
   5235 
   5236   changes to zic.c to allow hour values greater than 24 (along with
   5237   Paul's improved time value overflow checking)
   5238 
   5239 
   5240 Release 2007e - 2007-04-02 10:11:52 -0400
   5241 
   5242   Syria and Honduras changes by Paul Eggert
   5243 
   5244   zic.c variable renaming changes by Arthur David Olson
   5245 
   5246 
   5247 Release 2007d - 2007-03-20 08:48:30 -0400
   5248 
   5249   changes by Paul Eggert
   5250 
   5251   the elimination of white space at the ends of lines
   5252 
   5253 
   5254 Release 2007c - 2007-02-26 09:09:37 -0500
   5255 
   5256   changes by Paul Eggert
   5257 
   5258 
   5259 Release 2007b - 2007-02-12 09:34:20 -0500
   5260 
   5261   Paul Eggert's proposed change to the quotation handling logic in zic.c.
   5262 
   5263   changes to the commentary in "leapseconds" reflecting the IERS
   5264   announcement that there is to be no positive leap second at the end
   5265   of June 2007.
   5266 
   5267 
   5268 Release 2007a - 2007-01-08 12:28:29 -0500
   5269 
   5270   changes by Paul Eggert
   5271 
   5272   Derick Rethans's Asmara change
   5273 
   5274   Oscar van Vlijmen's Easter Island local mean time change
   5275 
   5276   symbolic link changes
   5277 
   5278 
   5279 Release 2006p - 2006-11-27 08:54:27 -0500
   5280 
   5281   changes by Paul Eggert
   5282 
   5283 
   5284 Release 2006o - 2006-11-06 09:18:07 -0500
   5285 
   5286   changes by Paul Eggert
   5287 
   5288 
   5289 Release 2006n - 2006-10-10 11:32:06 -0400
   5290 
   5291   changes by Paul Eggert
   5292 
   5293 
   5294 Release 2006m - 2006-10-02 15:32:35 -0400
   5295 
   5296   changes for Uruguay, Palestine, and Egypt by Paul Eggert
   5297 
   5298   (minimalist) changes to zic.8 to clarify "until" information
   5299 
   5300 
   5301 Release data2006l - 2006-09-18 12:58:11 -0400
   5302 
   5303   Paul's best-effort work on this coming weekend's Egypt time change
   5304 
   5305 
   5306 Release 2006k - 2006-08-28 12:19:09 -0400
   5307 
   5308   changes by Paul Eggert
   5309 
   5310 
   5311 Release 2006j - 2006-08-21 09:56:32 -0400
   5312 
   5313   changes by Paul Eggert
   5314 
   5315 
   5316 Release code2006i - 2006-08-07 12:30:55 -0400
   5317 
   5318   localtime.c fixes
   5319 
   5320   Ken Pizzini's conversion script
   5321 
   5322 
   5323 Release code2006h - 2006-07-24 09:19:37 -0400
   5324 
   5325   adds public domain notices to four files
   5326 
   5327   includes a fix for transition times being off by a second
   5328 
   5329   adds a new recording to the "arts" file (information courtesy Colin Bowern)
   5330 
   5331 
   5332 Release 2006g - 2006-05-08 17:18:09 -0400
   5333 
   5334   northamerica changes by Paul Eggert
   5335 
   5336 
   5337 Release 2006f - 2006-05-01 11:46:00 -0400
   5338 
   5339   a missing version number problem is fixed (with thanks to Bradley
   5340   White for catching the problem)
   5341 
   5342 
   5343 Release 2006d - 2006-04-17 14:33:43 -0400
   5344 
   5345   changes by Paul Eggert
   5346 
   5347   added new items to tz-arts.htm that were found by Paul
   5348 
   5349 
   5350 Release 2006c - 2006-04-03 10:09:32 -0400
   5351 
   5352   two sets of data changes by Paul Eggert
   5353 
   5354   a fencepost error fix in zic.c
   5355 
   5356   changes to zic.c and the "europe" file to minimize differences
   5357   between output produced by the old 32-bit zic and the new 64-bit
   5358   version
   5359 
   5360 
   5361 Release 2006b - 2006-02-20 10:08:18 -0500
   5362   [tz32code2006b + tz64code2006b + tzdata2006b]
   5363 
   5364   64-bit code
   5365 
   5366   All SCCS IDs were bumped to "8.1" for this release.
   5367 
   5368 
   5369 Release 2006a - 2006-01-30 08:59:31 -0500
   5370 
   5371   changes by Paul Eggert (in particular, Indiana time zone moves)
   5372 
   5373   an addition to the zic manual page to describe how special-case
   5374   transitions are handled
   5375 
   5376 
   5377 Release 2005r - 2005-12-27 09:27:13 -0500
   5378 
   5379   Canadian changes by Paul Eggert
   5380 
   5381   They also add "<pre>" directives to time zone data files and reflect
   5382   changes to warning message logic in "zdump.c" (but with calls to
   5383   "gettext" kept unbundled at the suggestion of Ken Pizzini).
   5384 
   5385 
   5386 Release 2005q - 2005-12-13 09:17:09 -0500
   5387 
   5388   Nothing earth-shaking here:
   5389 	1.  Electronic mail addresses have been removed.
   5390 	2.  Casts of the return value of exit have been removed.
   5391 	3.  Casts of the argument of is.* macros have been added.
   5392 	4.  Indentation in one section of zic.c has been fixed.
   5393 	5.  References to dead URLs in the data files have been dealt with.
   5394 
   5395 
   5396 Release 2005p - 2005-12-05 10:30:53 -0500
   5397 
   5398   "systemv", "tz-link.htm", and "zdump.c" changes
   5399   (less the casts of arguments to the is* macros)
   5400 
   5401 
   5402 Release 2005o - 2005-11-28 10:55:26 -0500
   5403 
   5404   Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
   5405 
   5406   zdump.c lint fixes by Arthur David Olson
   5407 
   5408 
   5409 Release 2005n - 2005-10-03 09:44:09 -0400
   5410 
   5411   changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
   5412   et al. changes)
   5413 
   5414 
   5415 Release 2005m - 2005-08-29 12:15:40 -0400
   5416 
   5417   changes by Paul Eggert (with a small tweak to the tz-art change)
   5418 
   5419   a declaration of an unused variable has been removed from zdump.c
   5420 
   5421 
   5422 Release 2005l - 2005-08-22 12:06:39 -0400
   5423 
   5424   changes by Paul Eggert
   5425 
   5426   overflow/underflow checks by Arthur David Olson, minus changes to
   5427   the "Theory" file about the pending addition of 64-bit data (I grow
   5428   less confident of the changes being accepted with each passing day,
   5429   and the changes no longer increase the data files nine-fold--there's
   5430   less than a doubling in size by my local Sun's reckoning)
   5431 
   5432 
   5433 Release 2005k - 2005-07-14 14:14:24 -0400
   5434 
   5435   The "leapseconds" file has been edited to reflect the recently
   5436   announced leap second at the end of 2005.
   5437 
   5438   I've also deleted electronic mail addresses from the files as an
   5439   anti-spam measure.
   5440 
   5441 
   5442 Release 2005j - 2005-06-13 14:34:13 -0400
   5443 
   5444   These reflect changes to limit the length of time zone abbreviations
   5445   and the characters used in those abbreviations.
   5446 
   5447   There are also changes to handle POSIX-style "quoted" timezone
   5448   environment variables.
   5449 
   5450   The changes were circulated on the time zone mailing list; the only
   5451   change since then was the removal of a couple of minimum-length of
   5452   abbreviation checks.
   5453 
   5454 
   5455 Release data2005i - 2005-04-21 15:04:16 -0400
   5456 
   5457   changes (most importantly to Nicaragua and Haiti) by Paul Eggert
   5458 
   5459 
   5460 Release 2005h - 2005-04-04 11:24:47 -0400
   5461 
   5462   changes by Paul Eggert
   5463 
   5464   minor changes to Makefile and zdump.c to produce more useful output
   5465   when doing a "make typecheck"
   5466 
   5467 
   5468 Release 2005g - 2005-03-14 10:11:21 -0500
   5469 
   5470   changes by Paul Eggert (a change to current DST rules in Uruguay and
   5471   an update to a link to time zone software)
   5472 
   5473 
   5474 Release 2005f - 2005-03-01 08:45:32 -0500
   5475 
   5476   data and documentation changes by Paul Eggert
   5477 
   5478 
   5479 Release 2005e - 2005-02-10 15:59:44 -0500
   5480 
   5481   [not summarized]
   5482 
   5483 
   5484 Release code2005d - 2005-01-31 09:21:47 -0500
   5485 
   5486   make zic complain about links to links if the -v flag is used
   5487 
   5488   have "make public" do more code checking
   5489 
   5490   add an include to "localtime.c" for the benefit of gcc systems
   5491 
   5492 
   5493 Release 2005c - 2005-01-17 18:36:29 -0500
   5494 
   5495   get better results when mktime runs on a system where time_t is double
   5496 
   5497   changes to the data files (most importantly to Paraguay)
   5498 
   5499 
   5500 Release 2005b - 2005-01-10 09:19:54 -0500
   5501 
   5502   Get localtime and gmtime working on systems with exotic time_t types.
   5503 
   5504   Update the leap second commentary in the "leapseconds" file.
   5505 
   5506 
   5507 Release 2005a - 2005-01-01 13:13:44 -0500
   5508 
   5509   [not summarized]
   5510 
   5511 
   5512 Release code2004i - 2004-12-14 13:42:58 -0500
   5513 
   5514   Deal with systems where time_t is unsigned.
   5515 
   5516 
   5517 Release code2004h - 2004-12-07 11:40:18 -0500
   5518 
   5519   64-bit-time_t changes
   5520 
   5521 
   5522 Release 2004g - 2004-11-02 09:06:01 -0500
   5523 
   5524   update to Cuba (taking effect this weekend)
   5525 
   5526   other changes by Paul Eggert
   5527 
   5528   correction of the spelling of Oslo
   5529 
   5530   changed versions of difftime.c and private.h
   5531 
   5532 
   5533 Release code2004f - 2004-10-21 10:25:22 -0400
   5534 
   5535   Cope with wide-ranging tm_year values.
   5536 
   5537 
   5538 Release 2004e - 2004-10-11 14:47:21 -0400
   5539 
   5540   Brazil/Argentina/Israel changes by Paul Eggert
   5541 
   5542   changes to tz-link.htm by Paul
   5543 
   5544   one small fix to Makefile
   5545 
   5546 
   5547 Release 2004d - 2004-09-22 08:27:29 -0400
   5548 
   5549   Avoid overflow problems when TM_YEAR_BASE is added to an integer.
   5550 
   5551 
   5552 Release 2004c - 2004-08-11 12:06:26 -0400
   5553 
   5554   asctime-related changes
   5555 
   5556   (variants of) some of the documentation changes suggested by Paul Eggert
   5557 
   5558 
   5559 Release 2004b - 2004-07-19 14:33:35 -0400
   5560 
   5561   data changes by Paul Eggert - most importantly, updates for Argentina
   5562 
   5563 
   5564 Release 2004a - 2004-05-27 12:00:47 -0400
   5565 
   5566   changes by Paul Eggert
   5567 
   5568   Handle DST transitions that occur at the end of a month in some
   5569   years but at the start of the following month in other years.
   5570 
   5571   Add a copy of the correspondence that's the basis for claims about
   5572   DST in the Navajo Nation.
   5573 
   5574 
   5575 Release 2003e - 2003-12-15 09:36:47 -0500
   5576 
   5577   changes by Arthur David Olson (primarily code changes)
   5578 
   5579   changes by Paul Eggert (primarily data changes)
   5580 
   5581   minor changes to "Makefile" and "northamerica" (in the latter case,
   5582   optimization of the "Toronto" rules)
   5583 
   5584 
   5585 Release 2003d - 2003-10-06 09:34:44 -0400
   5586 
   5587   changes by Paul Eggert
   5588 
   5589 
   5590 Release 2003c - 2003-09-16 10:47:05 -0400
   5591 
   5592   Fix bad returns in zic.c's inleap function.
   5593   Thanks to Bradley White for catching the problem!
   5594 
   5595 
   5596 Release 2003b - 2003-09-16 07:13:44 -0400
   5597 
   5598   Add a "--version" option (and documentation) to the zic and zdump commands.
   5599 
   5600   changes to overflow/underflow checking in zic
   5601 
   5602   a localtime typo fix.
   5603 
   5604   Update the leapseconds and tz-art.htm files.
   5605 
   5606 
   5607 Release 2003a - 2003-03-24 09:30:54 -0500
   5608 
   5609   changes by Paul Eggert
   5610 
   5611   a few additions and modifications to the tz-art.htm file
   5612 
   5613 
   5614 Release 2002d - 2002-10-15 13:12:42 -0400
   5615 
   5616   changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
   5617 
   5618   There's also a new time zone quote in "tz-art.htm".
   5619 
   5620 
   5621 Release 2002c - 2002-04-04 11:55:20 -0500
   5622 
   5623   changes by Paul Eggert
   5624 
   5625   Change zic.c to avoid creating symlinks to files that don't exist.
   5626 
   5627 
   5628 Release 2002b - 2002-01-28 12:56:03 -0500
   5629 
   5630   [These change notes are for Release 2002a, which was corrupted.
   5631   2002b was a corrected version of 2002a.]
   5632 
   5633   changes by Paul Eggert
   5634 
   5635   Update the "leapseconds" file to note that there'll be no leap
   5636   second at the end of June, 2002.
   5637 
   5638   Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
   5639 
   5640   Change to "difftime.c" to avoid sizeof problems.
   5641 
   5642 
   5643 Release 2001d - 2001-10-09 13:31:32 -0400
   5644 
   5645   changes by Paul Eggert
   5646 
   5647 
   5648 Release 2001c - 2001-06-05 13:59:55 -0400
   5649 
   5650   changes by Paul Eggert and Andrew Brown
   5651 
   5652 
   5653 Release 2001b - 2001-04-05 16:44:38 -0400
   5654 
   5655   changes by Paul Eggert (modulo jnorgard's typo fix)
   5656 
   5657   tz-art.htm has been HTMLified.
   5658 
   5659 
   5660 Release 2001a - 2001-03-13 12:57:44 -0500
   5661 
   5662   changes by Paul Eggert
   5663 
   5664   An addition to the "leapseconds" file: comments with the text of the
   5665   latest IERS leap second notice.
   5666 
   5667   Trailing white space has been removed from data file lines, and
   5668   repeated spaces in "Rule Jordan" lines in the "asia" file have been
   5669   converted to tabs.
   5670 
   5671 
   5672 Release 2000h - 2000-12-14 15:33:38 -0500
   5673 
   5674   changes by Paul Eggert
   5675 
   5676   one typo fix in the "art" file
   5677 
   5678   With providence, this is the last update of the millennium.
   5679 
   5680 
   5681 Release 2000g - 2000-10-10 11:35:22 -0400
   5682 
   5683   changes by Paul Eggert
   5684 
   5685   correction of John Mackin's name submitted by Robert Elz
   5686 
   5687   Garry Shandling's Daylight Saving Time joke (!?!) from the recent
   5688   Emmy Awards broadcast.
   5689 
   5690 
   5691 Release 2000f - 2000-08-10 09:31:58 -0400
   5692 
   5693   changes by Paul Eggert
   5694 
   5695   Added information in "tz-art.htm" on a Seinfeld reference to DST.
   5696 
   5697   Error checking and messages in the "yearistype" script have been
   5698   improved.
   5699 
   5700 
   5701 Release 2000e - 2000-07-31 09:27:54 -0400
   5702 
   5703   data changes by Paul Eggert
   5704 
   5705   a change to the default value of the defined constant HAVE_STRERROR
   5706 
   5707   the addition of a Dave Barry quote on DST to the tz-arts file
   5708 
   5709 
   5710 Release 2000d - 2000-04-20 15:43:04 -0400
   5711 
   5712   changes to the documentation and code of strftime for C99 conformance
   5713 
   5714   a bug fix for date.c
   5715 
   5716   These are based on (though modified from) changes by Paul Eggert.
   5717 
   5718 
   5719 Release 2000c - 2000-03-04 10:31:43 -0500
   5720 
   5721   changes by Paul Eggert
   5722 
   5723 
   5724 Release 2000b - 2000-02-21 12:16:29 -0500
   5725 
   5726   changes by Paul Eggert and Joseph Myers
   5727 
   5728   modest tweaks to the tz-art.htm and tz-link.htm files
   5729 
   5730 
   5731 Release 2000a - 2000-01-18 09:21:26 -0500
   5732 
   5733   changes by Paul Eggert
   5734 
   5735   The two hypertext documents have also been renamed.
   5736 
   5737 
   5738 Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
   5739 
   5740   Paul Eggert's changes
   5741 
   5742   additions to the "zic" manual page and the "Arts.htm" file
   5743 
   5744 
   5745 Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
   5746 
   5747   [not summarized]
   5748 
   5749 
   5750 Release data1999h - 1999-10-07 03:50:29 -0400
   5751 
   5752   changes by Paul Eggert to "europe" (most importantly, fixing
   5753   Lithuania and Estonia)
   5754 
   5755 
   5756 Release 1999g - 1999-09-28 11:06:18 -0400
   5757 
   5758   data changes by Paul Eggert (most importantly, the change for
   5759   Lebanon that buys correctness for this coming Sunday)
   5760 
   5761   The "code" file contains changes to "Makefile" and "checktab.awk" to
   5762   allow better checking of time zone files before they are published.
   5763 
   5764 
   5765 Release 1999f - 1999-09-23 09:48:14 -0400
   5766 
   5767   changes by Arthur David Olson and Paul Eggert
   5768 
   5769 
   5770 Release 1999e - 1999-08-17 15:20:54 -0400
   5771 
   5772   changes circulated by Paul Eggert, although the change to handling
   5773   of DST-specifying timezone names has been commented out for now
   5774   (search for "XXX" in "localtime.c" for details).  These files also
   5775   do not make any changes to the start of DST in Brazil.
   5776 
   5777   In addition to Paul's changes, there are updates to "Arts.htm" and
   5778   cleanups of URLs.
   5779 
   5780 
   5781 Release 1999d - 1999-03-30 11:31:07 -0500
   5782 
   5783   changes by Paul Eggert
   5784 
   5785   The Makefile's "make public" rule has also been changed to do a test
   5786   compile of each individual time zone data file (which should help
   5787   avoid problems such as the one we had with Nicosia).
   5788 
   5789 
   5790 Release 1999c - 1999-03-25 09:47:47 -0500
   5791 
   5792   changes by Paul Eggert, most importantly the change for Chile.
   5793 
   5794 
   5795 Release 1999b - 1999-02-01 17:51:44 -0500
   5796 
   5797   changes by Paul Eggert
   5798 
   5799   code changes (suggested by Mani Varadarajan, mani at be.com) for
   5800   correct handling of symbolic links when building using a relative directory
   5801 
   5802   code changes to generate correct messages for failed links
   5803 
   5804   updates to the URLs in Arts.htm
   5805 
   5806 
   5807 Release 1999a - 1999-01-19 16:20:29 -0500
   5808 
   5809   error message internationalizations and corrections in zic.c and
   5810   zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
   5811   to whom thanks!)
   5812 
   5813 
   5814 Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
   5815 
   5816   changes for Brazil, Chile, and Germany
   5817 
   5818   support for use of "24:00" in the input files for the time zone compiler
   5819 
   5820 
   5821 Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
   5822 
   5823   changes by Paul Eggert
   5824 
   5825   correction to a define in the "private.h" file
   5826 
   5827 
   5828 Release data1998g - 1998-08-11 03:28:35 -0000
   5829   [tzdata1998g.tar.gz is missing!]
   5830 
   5831   Lithuanian change provided by mgedmin at pub.osf.it
   5832 
   5833   Move creation of the GMT link with Etc/GMT to "etcetera" (from
   5834   "backward") to ensure that the GMT file is created even where folks
   5835   don't want the "backward" links (as suggested by Paul Eggert).
   5836 
   5837 
   5838 Release data1998f - 1998-07-20 13:50:00 -0000
   5839   [tzdata1998f.tar.gz is missing!]
   5840 
   5841   Update the "leapseconds" file to include the newly announced
   5842   insertion at the end of 1998.
   5843 
   5844 
   5845 Release code1998f - 1998-06-01 10:18:31 -0400
   5846 
   5847   addition to localtime.c by Guy Harris
   5848 
   5849 
   5850 Release 1998e - 1998-05-28 09:56:26 -0400
   5851 
   5852   The Makefile is changed to produce zoneinfo-posix rather than
   5853   zoneinfo/posix, and to produce zoneinfo-leaps rather than
   5854   zoneinfo/right.
   5855 
   5856   data changes by Paul Eggert
   5857 
   5858   changes from Guy Harris to provide asctime_r and ctime_r
   5859 
   5860   A usno1998 file (substantially identical to usno1997) has been added.
   5861 
   5862 
   5863 Release 1998d - 1998-05-14 11:58:34 -0400
   5864 
   5865   changes to comments (in particular, elimination of references to CIA maps).
   5866   "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
   5867   where changes occur.
   5868 
   5869 
   5870 Release 1998c - 1998-02-28 12:32:26 -0500
   5871 
   5872   changes by Paul Eggert (save the "French correction," on which I'll
   5873   wait for the dust to settle)
   5874 
   5875   symlink changes
   5876 
   5877   changes and additions to Arts.htm
   5878 
   5879 
   5880 Release 1998b - 1998-01-17 14:31:51 -0500
   5881 
   5882   URL cleanups and additions
   5883 
   5884 
   5885 Release 1998a - 1998-01-13 12:37:35 -0500
   5886 
   5887   changes by Paul Eggert
   5888 
   5889 
   5890 Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
   5891 
   5892   changes by Paul Eggert, with minor modifications from Arthur David
   5893   Olson to make the files more browser friendly
   5894 
   5895 
   5896 Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
   5897 
   5898   minor changes to put "TZif" at the start of each timezone information file
   5899 
   5900   a rule has also been added to the Makefile so you can
   5901 	make zones
   5902   to just recompile the zone information files (rather than doing a
   5903   full "make install" with its other effects).
   5904 
   5905 
   5906 Release data1997i - 1997-10-07 08:45:38 -0400
   5907 
   5908   changes to Africa by Paul Eggert
   5909 
   5910 
   5911 Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
   5912 
   5913   corrections for Uruguay (and other locations)
   5914 
   5915   Arthur David Olson's simple-minded fix allowing mktime to both
   5916   correctly handle leap seconds and correctly handle tm_sec values
   5917   upon which arithmetic has been performed.
   5918 
   5919 
   5920 Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
   5921 
   5922   Paul Eggert's updates
   5923 
   5924   a small change to a function prototype;
   5925 
   5926   "Music" has been renamed "Arts.htm", HTMLified, and augmented to
   5927   include information on Around the World in Eighty Days.
   5928 
   5929 
   5930 Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
   5931 
   5932   fixes to zic's error handling
   5933 
   5934   changes inspired by the item circulated on Slovenia
   5935 
   5936   The description of Web resources has been HTMLified for browsing
   5937   convenience.
   5938 
   5939   A new piece of tz-related music has been added to the "Music" file.
   5940 
   5941 
   5942 Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
   5943 
   5944   Paul Eggert's latest suggestions
   5945 
   5946 
   5947 Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
   5948 
   5949   changes to "zic.c" to correct performance of the "-s" option
   5950 
   5951   a new file "usno1997"
   5952 
   5953 
   5954 Release data1997c - 1997-03-04 09:58:18 -0500
   5955 
   5956   changes in Israel
   5957 
   5958 
   5959 Release 1997b - 1997-02-27 18:34:19 -0500
   5960 
   5961   The data file incorporates the 1997 leap second.
   5962 
   5963   The code file incorporates Arthur David Olson's take on the
   5964   zic/multiprocessor/directory-creation situation.
   5965 
   5966 
   5967 Release 1997a - 1997-01-21 09:11:10 -0500
   5968 
   5969   Paul Eggert's Antarctica (and other changes)
   5970 
   5971   Arthur David Olson finessed the "getopt" issue by checking against
   5972   both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
   5973   is returned while SunOS 5.5's manual says EOF is returned).
   5974 
   5975 
   5976 Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
   5977 
   5978   Paul Eggert's latest changes
   5979 
   5980 
   5981 Release code1996n - 1996-12-16 09:42:02 -0500
   5982 
   5983   link snapping fix from Bruce Evans (via Garrett Wollman)
   5984 
   5985 
   5986 Release data1996m - 1996-11-24 02:37:34 -0000
   5987   [tzdata1996m.tar.gz is missing!]
   5988 
   5989   Paul Eggert's batch of changes
   5990 
   5991 
   5992 Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
   5993 
   5994   No functional changes here; the files have simply been changed to
   5995   make more use of ISO style dates in comments. The names of the above
   5996   files now include the year in full.
   5997 
   5998 
   5999 Release code96l - 1996-09-08 17:12:20 -0400
   6000 
   6001   tzcode96k was missing a couple of pieces.
   6002 
   6003 
   6004 Release 96k - 1996-09-08 16:06:22 -0400
   6005 
   6006   the latest round of changes from Paul Eggert
   6007 
   6008   the recent Year 2000 material
   6009 
   6010 
   6011 Release code96j - 1996-07-30 13:18:53 -0400
   6012 
   6013   Set sp->typecnt as suggested by Timothy Patrick Murphy.
   6014 
   6015 
   6016 Release code96i - 1996-07-27 20:11:35 -0400
   6017 
   6018   Paul's suggested patch for strftime %V week numbers
   6019 
   6020 
   6021 Release data96i - 1996-07-01 18:13:04 -0400
   6022 
   6023   "northamerica" and "europe" changes by Paul Eggert
   6024 
   6025 
   6026 Release code96h - 1996-06-05 08:02:21 -0400
   6027 
   6028   fix for handling transitions specified in Universal Time
   6029 
   6030   Some "public domain" notices have also been added.
   6031 
   6032 
   6033 Release code96g - 1996-05-16 14:00:26 -0400
   6034 
   6035   fix for the simultaneous-DST-and-zone-change challenge
   6036 
   6037 
   6038 Release data96h - 1996-05-09 17:40:51 -0400
   6039 
   6040   changes by Paul Eggert
   6041 
   6042 
   6043 Release code96f-data96g - 1996-05-03 03:09:59 -0000
   6044   [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
   6045 
   6046   The changes get us some of the way to fixing the problems noted in Paul
   6047   Eggert's letter yesterday (in addition to a few others).  The approach
   6048   has been to make zic a bit smarter about figuring out what time zone
   6049   abbreviations apply just after the time specified in the "UNTIL" part
   6050   of a zone line.  Putting the smarts in zic means avoiding having
   6051   transition times show up in both "Zone" lines and "Rule" lines, which
   6052   in turn avoids multiple transition time entries in time zone files.
   6053   (This also makes the zic input files such as "europe" a bit shorter and
   6054   should ease maintenance.)
   6055 
   6056 
   6057 Release data96f - 1996-04-19 19:20:03 -0000
   6058   [tzdata96f.tar.gz is missing!]
   6059 
   6060   The only changes are to the "northamerica" file; the time zone
   6061   abbreviation for Denver is corrected to MST (and MDT), and the
   6062   comments for Mexico have been updated.
   6063 
   6064 
   6065 Release data96e - 1996-03-19 17:37:26 -0500
   6066 
   6067   Proposals by Paul Eggert, in particular the Portugal change that
   6068   comes into play at the end of this month.
   6069 
   6070 
   6071 Release data96d - 1996-03-18 20:49:39 -0500
   6072 
   6073   [not summarized]
   6074 
   6075 
   6076 Release code96e - 1996-02-29 15:43:27 -0000
   6077   [tzcode96e.tar.gz is missing!]
   6078 
   6079   internationalization changes and the fix to the documentation for strftime
   6080 
   6081 
   6082 Release code96d-data96c - 1996-02-12 11:05:27 -0500
   6083 
   6084   The "code" file simply updates Bob Kridle's electronic address.
   6085 
   6086   The "data" file updates rules for Mexico.
   6087 
   6088 
   6089 Release data96b - 1996-01-27 15:44:42 -0500
   6090 
   6091   Kiribati change
   6092 
   6093 
   6094 Release code96c - 1996-01-16 16:58:15 -0500
   6095 
   6096   leap-year streamlining and binary-search changes
   6097 
   6098   fix to newctime.3
   6099 
   6100 
   6101 Release code96b - 1996-01-10 20:42:39 -0500
   6102 
   6103   fixes and enhancements from Paul Eggert, including code that
   6104   emulates the behavior of recent versions of the SunOS "date"
   6105   command.
   6106 
   6107 
   6108 Release 96a - 1996-01-06 09:08:24 -0500
   6109 
   6110   Israel updates
   6111 
   6112   fixes to strftime.c for correct ISO 8601 week number generation,
   6113   plus support for two new formats ('G' and 'g') to give ISO 8601 year
   6114   numbers (which are not necessarily the same as calendar year numbers)
   6115 
   6116 
   6117 Release code95i-data95m - 1995-12-21 12:46:47 -0500
   6118 
   6119   The latest revisions from Paul Eggert are included, the usno1995
   6120   file has been updated, and a new file ("WWW") covering useful URLs
   6121   has been added.
   6122 
   6123 
   6124 Release code95h-data95l - 1995-12-19 18:10:12 -0500
   6125 
   6126   A simplification of a macro definition, a change to data for Sudan,
   6127   and (for last minute shoppers) notes in the "Music" file on the CD
   6128   "Old Man Time".
   6129 
   6130 
   6131 Release code95g-data95k - 1995-10-30 10:32:47 -0500
   6132 
   6133   (slightly reformatted) 8-bit-clean proposed patch
   6134 
   6135   minor patch: US/Eastern -> America/New_York
   6136 
   6137   snapshot of the USNO's latest data ("usno1995")
   6138 
   6139   some other minor cleanups
   6140 
   6141 
   6142 Release code95f-data95j - 1995-10-28 21:01:34 -0000
   6143   [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
   6144 
   6145   European cleanups
   6146 
   6147   support for 64-bit time_t's
   6148 
   6149   optimization in localtime.c
   6150 
   6151 
   6152 Release code95e - 1995-10-13 13:23:57 -0400
   6153 
   6154   the mktime change to scan from future to past when trying to find time zone
   6155   offsets
   6156 
   6157 
   6158 Release data95i - 1995-09-26 10:43:26 -0400
   6159 
   6160   For Canada/Central, guess that the Sun customer's "one week too
   6161   early" was just a approximation, and the true error is one month
   6162   too early.  This is consistent with the rest of Canada.
   6163 
   6164 
   6165 Release data95h - 1995-09-21 11:26:48 -0400
   6166 
   6167   latest changes from Paul Eggert
   6168 
   6169 
   6170 Release code95d - 1995-09-14 11:14:45 -0400
   6171 
   6172   the addition of a "Music" file, which documents four recorded
   6173   versions of the tune "Save That Time".
   6174 
   6175 
   6176 Release data95g - 1995-09-01 17:21:36 -0400
   6177 
   6178   "yearistype" correction
   6179 
   6180 
   6181 Release data95f - 1995-08-28 20:46:56 -0400
   6182 
   6183   Paul Eggert's change to the australasia file
   6184 
   6185 
   6186 Release data95e - 1995-07-08 18:02:34 -0400
   6187 
   6188   The only change is a leap second at the end of this year.
   6189   Thanks to Bradley White for forwarding news on the leap second.
   6190 
   6191 
   6192 Release data95d - 1995-07-03 13:26:22 -0400
   6193 
   6194   Paul Eggert's changes
   6195 
   6196 
   6197 Release data95c - 1995-07-02 19:19:28 -0400
   6198 
   6199   changes to "asia", "backward", "europe", and "southamerica"
   6200   (read: northamericacentrics need not apply)
   6201 
   6202 
   6203 Release code95c - 1995-03-13 14:00:46 -0500
   6204 
   6205   one-line fix for sign extension problems in detzcode
   6206 
   6207 
   6208 Release 95b - 1995-03-04 11:22:38 -0500
   6209 
   6210   Minor changes in both:
   6211 
   6212   The "code" file contains a workaround for the lack of "unistd.h" in
   6213   Microsoft C++ version 7.
   6214 
   6215   The "data" file contains a fixed "Link" for America/Shiprock.
   6216 
   6217 
   6218 Release 94h - 1994-12-10 12:51:14 -0500
   6219 
   6220   The files:
   6221 
   6222   *	incorporate the changes to "zdump" and "date" to make changes to
   6223 	the "TZ" environment variable permanent;
   6224 
   6225   *	incorporate the table changes by Paul Eggert;
   6226 
   6227   *	include (and document) support for universal time specifications in
   6228 	data files - but do not (yet) include use of this feature in the
   6229 	data files.
   6230 
   6231   Think of this as "TZ Classic" - the software has been set up not to break if
   6232   universal time shows up in its input, and data entries have been
   6233   left as is so as not to break existing implementations.
   6234 
   6235 
   6236 Release data94f - 1994-08-20 12:56:09 -0400
   6237 
   6238   (with thanks!) the latest data updates from Paul Eggert
   6239 
   6240 
   6241 Release data94e - 1994-06-04 13:13:53 -0400
   6242 
   6243   [not summarized]
   6244 
   6245 
   6246 Release code94g - 1994-05-05 12:14:07 -0400
   6247 
   6248   fix missing "optind.c" and a reference to it in the Makefile
   6249 
   6250 
   6251 Release code94f - 1994-05-05 13:00:33 -0000
   6252   [tzcode94f.tar.gz is missing!]
   6253 
   6254   changes to avoid overflow in difftime, as well as changes to cope
   6255   with the 52/53 challenge in strftime
   6256 
   6257 
   6258 Release code94e - 1994-03-30 23:32:59 -0500
   6259 
   6260   change for the benefit of PCTS
   6261 
   6262 
   6263 Release 94d - 1994-02-24 15:42:25 -0500
   6264 
   6265   Avoid clashes with POSIX semantics for zones such as GMT+4.
   6266 
   6267   Some other very minor housekeeping is also present.
   6268 
   6269 
   6270 Release code94c - 1994-02-10 08:52:40 -0500
   6271 
   6272   Fix bug where mkdirs was broken unless you compile with
   6273   -fwritable-strings (which is generally losing to do).
   6274 
   6275 
   6276 Release 94b - 1994-02-07 10:04:33 -0500
   6277 
   6278   work by Paul Eggert who notes:
   6279 
   6280   I found another book of time zone histories by E W Whitman; it's not
   6281   as extensive as Shanks but has a few goodies of its own.  I used it
   6282   to update the tables.  I also fixed some more as a result of
   6283   correspondence with Adam David and Peter Ilieve, and move some stray
   6284   links from 'europe' to 'backward'.  I corrected some scanning errors
   6285   in usno1989.
   6286 
   6287   As far as the code goes, I fixed zic to allow years in the range
   6288   INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
   6289   And I cleaned up the zic documentation a little bit.
   6290 
   6291 
   6292 Release data94a - 1994-02-03 08:58:54 -0500
   6293 
   6294   It simply incorporates the recently announced leap second into the
   6295   "leapseconds" file.
   6296 
   6297 
   6298 Release 93g - 1993-11-22 17:28:27 -0500
   6299 
   6300   Paul Eggert has provided a good deal of historic information (based
   6301   on Shanks), and there are some code changes to deal with the buglets
   6302   that crawled out in dealing with the new information.
   6303 
   6304 
   6305 Release 93f - 1993-10-15 12:27:46 -0400
   6306 
   6307   Paul Eggert's changes
   6308 
   6309 
   6310 Release 93e - 1993-09-05 21:21:44 -0400
   6311 
   6312   This has updated data for Israel, England, and Kwajalein.  There's
   6313   also an update to "zdump" to cope with Kwajalein's 24-hour jump.
   6314   Thanks to Paul Eggert and Peter Ilieve for the changes.
   6315 
   6316 
   6317 Release 93d - 1993-06-17 23:34:17 -0400
   6318 
   6319   new fix and new data on Israel
   6320 
   6321 
   6322 Release 93c - 1993-06-06 19:31:55 -0400
   6323 
   6324   [not summarized]
   6325 
   6326 
   6327 Release 93b - 1993-02-02 14:53:58 -0500
   6328 
   6329   updated "leapseconds" file
   6330 
   6331 
   6332 Release 93 - 1993-01-08 07:01:06 -0500
   6333 
   6334   At kre's suggestion, the package has been split in two - a code piece
   6335   (which also includes documentation) that's only of use to folks who
   6336   want to recompile things and a data piece useful to anyone who can
   6337   run "zic".
   6338 
   6339   The new version has a few changes to the data files, a few
   6340   portability changes, and an off-by-one fix (with thanks to
   6341   Tom Karzes at deshaw.com for providing a description and a
   6342   solution).
   6343 
   6344 
   6345 Release 92c - 1992-11-21 17:35:36 -0000
   6346   [tz92c.tar.Z is missing!]
   6347 
   6348   The fallout from the latest round of DST transitions.
   6349 
   6350   There are changes for Portugal, Saskatchewan, and "Pacific-New";
   6351   there's also a change to "zic.c" that makes it portable to more systems.
   6352 
   6353 
   6354 Release 92 - 1992-04-25 18:17:03 -0000
   6355   [tz92.tar.Z is missing!]
   6356 
   6357   By popular demand (well, at any rate, following a request by kre at munnari)
   6358 
   6359 
   6360 The 1989 update of the time zone package featured:
   6361 
   6362   *	POSIXization (including interpretation of POSIX-style TZ environment
   6363 	variables, provided by Guy Harris),
   6364   *	ANSIfication (including versions of "mktime" and "difftime"),
   6365   *	SVIDulation (an "altzone" variable)
   6366   *	MACHination (the "gtime" function)
   6367   *	corrections to some time zone data (including corrections to the rules
   6368 	for Great Britain and New Zealand)
   6369   *	reference data from the United States Naval Observatory for folks who
   6370 	want to do additional time zones
   6371   *	and the 1989 data for Saudi Arabia.
   6372 
   6373   (Since this code will be treated as "part of the implementation" in some
   6374   places and as "part of the application" in others, there's no good way to
   6375   name functions, such as timegm, that are not part of the proposed ANSI C
   6376   standard; such functions have kept their old, underscore-free names in this
   6377   update.)
   6378 
   6379   And the "dysize" function has disappeared; it was present to allow
   6380   compilation of the "date" command on old BSD systems, and a version of "date"
   6381   is now provided in the package.  The "date" command is not created when you
   6382   "make all" since it may lack options provided by the version distributed with
   6383   your operating system, or may not interact with the system in the same way
   6384   the native version does.
   6385 
   6386   Since POSIX frowns on correct leap second handling, the default behavior of
   6387   the "zic" command (in the absence of a "-L" option) has been changed to omit
   6388   leap second information from its output files.
   6389 
   6390 
   6391 -----
   6392 Notes
   6393 
   6394 This file contains copies of the part of each release announcement
   6395 that talks about the changes in that release.  The text has been
   6396 adapted and reformatted for the purposes of this file.
   6397 
   6398 Traditionally a release R consists of a pair of tarball files,
   6399 tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
   6400 code2010a, data2012c) consist of just one or the other tarball, and a
   6401 few (e.g., code2012c-data2012d) have tarballs with mixed version
   6402 numbers.  Recent releases also come in an experimental format
   6403 consisting of a single tarball tzdb-R.tar.lz with extra data.
   6404 
   6405 Release timestamps are taken from the release's commit (for newer,
   6406 Git-based releases), from the newest file in the tarball (for older
   6407 releases, where this info is available) or from the email announcing
   6408 the release (if all else fails; these are marked with a time zone
   6409 abbreviation of -0000 and an "is missing!" comment).
   6410 
   6411 Earlier versions of the code and data were not announced on the tz
   6412 list and are not summarized here.
   6413 
   6414 This file is in the public domain.
   6415 
   6416 Local Variables:
   6417 coding: utf-8
   6418 End:
   6419