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NEWS
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NEWS
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News for the tz database
Unreleased, experimental changes
Briefly: Fiji ends DST 2018-01-14, not 2018-01-21.
Namibia switches from +01/+02 to +02 on 2018-04-01.
Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
A new file tzdata.zi now holds a small text copy of all data.
The zic input format has been regularized slightly.
Changes to future time stamps
Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
predicted. (Thanks to Dominic Fok.) Adjust future predictions
accordingly.
Namibia will switch from +01 with DST to +02 all year on
2017-09-03 at 02:00. This affects UT offsets starting 2018-04-01
at 02:00. (Thanks to Steffen Thorsen.)
Turks & Caicos will switch from -04 all year to -05 with US DST on
2018-04-01 at 00:00. This affects UT offsets starting 2018-11-04
at 02:00. (Thanks to Steffen Thorsen.)
Changes to past time stamps
Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
(Thanks to Arthur David Olson.)
Detroit did not observe DST in 1967.
Use railway time for Asia/Kolkata before 1941, by switching to
Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
1906. Also, treat 1941-2's +0630 as DST, like 1942-5.
Europe/Dublin's 1946 and 1947 fallback transitions occurred at
02:00 standard time, not 02:00 DST. (Thanks to Michael Deckers.)
Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
American time in 1892, not 1879. (Thanks to Michael Deckers.)
Adjust the 1867 transition in Alaska to better reflect the
historical record, by changing it to occur on 1867-10-18 at 15:30
Sitka time rather than at the start of 1867-10-17 local time.
Although strictly speaking this is accurate only for Sitka,
the rest of Alaska's blanks need to be filled in somehow.
Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
(Thanks to Michael Deckers.)
Add 7 s to the UT offset in Asia/Yangon before 1920.
Changes to zone names
Remove Canada/East-Saskatchewan from the 'backward' file, as it
exceeded the 14-character limit and was an unused misnomer anyway.
Changes to build procedure
To support applications that prefer to read time zone data in text
form, two zic input files tzdata.zi and leapseconds are now
installed by default. The commands 'zic tzdata.zi' and 'zic -L
leapseconds tzdata.zi' can reproduce the tzdata binary files
without and with leap seconds, respectively. To prevent these two
new files from being installed, use 'make TZDATA_TEXT=', and to
suppress leap seconds from the tzdata text installation, use 'make
TZDATA_TEXT=tzdata.zi'.
'make BACKWARD=' now suppresses backward-compatibility names
like 'US/Pacific' that are defined in the 'backward' and
'pacificnew' files.
'make check' now works on systems that lack a UTF-8 locale,
or that lack the nsgmls program. Set UTF8_LOCALE to configure
the name of a UTF-8 locale, if you have one.
Y2K runtime checks are no longer enabled by default. Add
-DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
to disable them. (New name suggested by Brian Inglis.)
The build procedure for zdump now works on AIX 7.1.
(Problem reported by Kees Dekker.)
Changes to code
zic and the reference runtime now reject multiple leap seconds
within 28 days of each other, or leap seconds before the Epoch.
As a result, support for double leap seconds, which was
obsolescent and undocumented, has been removed. Double leap
seconds were an error in the C89 standard; they have never existed
in civil timekeeping. (Thanks to Robert Elz and Bradley White for
noticing glitches in the code that uncovered this problem.)
zic now warns about use of the obsolescent and undocumented -y
option, and about use of the obsolescent TYPE field of Rule lines.
zic now allows unambiguous abbreviations like "Sa" and "Su" for
weekdays; formerly it rejected them due to a bug. Conversely, zic
no longer considers non-prefixes to be abbreviations; for example,
it no longer accepts "lF" as an abbreviation for "lastFriday".
Also, zic warns about the undocumented usage with a "last-"
prefix, e.g., "last-Fri".
Similarly, zic now accepts the unambiguous abbreviation "L" for
"Link" in ordinary context and for "Leap" in leap-second context.
Conversely, zic no longer accepts non-prefixes such as "La" as
abbreviations for words like "Leap".
zic no longer accepts leap second lines in ordinary input, or
ordinary lines in leap second input. Formerly, zic sometimes
warned about this undocumented usage and handled it incorrectly.
The new macro HAVE_TZNAME governs whether the tzname external
variable is exported, instead of USG_COMPAT. USG_COMPAT now
governs only the external variables "timezone" and "daylight".
This change is needed because the three variables are not in the
same category: although POSIX requires tzname, it specifies the
other two variables as optional. Also, USG_COMPAT is now 1 or 0:
if not defined, the code attempts to guess it from other macros.
localtime.c and difftime.c no longer require stdio.h, and .c files
other than zic.c no longer require sys/wait.h.
zdump.c no longer assumes snprintf. (Reported by Jonathan Leffler.)
Calculation of time_t extrema works around a bug in GCC 4.8.4
(Reported by Stan Shebs and Joseph Myers.)
zic.c no longer mistranslates formats of line numbers in non-English
locales. (Problem reported by Benno Schulenberg.)
Several minor changes have been made to the code to make it a
bit easier to port to MS-Windows and Solaris. (Thanks to Kees
Dekker for reporting the problems.)
Changes to documentation and commentary
The zic man page now documents abbreviation rules.
tz-link.htm now covers how to apply tzdata changes to clients.
(Thanks to Jorge Fábregas for the AIX link.) It also mentions MySQL.
The leap-seconds.list URL has been updated to something that is
more reliable for tzdb. (Thanks to Tim Parenti and Brian Inglis.)
Release 2017b - 2017-03-17 07:30:38 -0700
Briefly: Haiti has resumed DST.
Changes to past and future time stamps
Haiti resumed observance of DST in 2017. (Thanks to Steffen Thorsen.)
Changes to past time stamps
Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
is one byte over the POSIX limit. (Problem reported by Derick Rethans.)
Changes to code
The reference localtime implementation now falls back on the
current US daylight-saving transition rules rather than the
1987-2006 rules. This fallback occurs only when (1) the TZ
environment variable's value has a name like "AST4ADT" that asks
for daylight saving time but does not specify the rules, (2) there
is no file by that name, and (3) the TZDEFRULES file cannot be
loaded. (Thanks to Tom Lane.)
Release 2017a - 2017-02-28 00:05:36 -0800
Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
discontinues DST.
Changes to future time stamps
Mongolia no longer observes DST. (Thanks to Ganbold Tsagaankhuu.)
Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
Its clocks diverge from America/Santiago starting 2017-05-13 at
23:00, hiving off a new zone America/Punta_Arenas. Although the
Chilean government says this change expires in May 2019, for now
assume it's permanent. (Thanks to Juan Correa and Deborah
Goldsmith.) This also affects Antarctica/Palmer.
Changes to past time stamps
Fix many entries for historical time stamps for Europe/Madrid
before 1979, to agree with tables compiled by Pere Planesas of the
National Astronomical Observatory of Spain. As a side effect,
this changes some time stamps for Africa/Ceuta before 1929, which
are probably guesswork anyway. (Thanks to Steve Allen and
Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
correcting the 1901 transition.)
Ecuador observed DST from 1992-11-28 to 1993-02-05.
(Thanks to Alois Treindl.)
Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
(Thanks to Stepan Golosunov.)
Changes to past and future time zone abbreviations
Switch to numeric time zone abbreviations for South America, as
part of the ongoing project of removing invented abbreviations.
This avoids the need to invent an abbreviation for the new Chilean
new zone. Similarly, switch from invented to numeric time zone
abbreviations for Afghanistan, American Samoa, the Azores,
Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
for half-hour daylight saving time in Belize before 1944 and in
the Dominican Republic before 1975; and for Canary Islands before
1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
Indian Summer Time before 1942, for Indonesia before around 1964,
for Kenya before 1960, for Liberia before 1973, for Madeira before
1967, for Namibia before 1943, for the Netherlands in 1937-9, for
Pakistan before 1971, for Western Sahara before 1977, and for
Zaporozhye in 1880-1924.
For Alaska time from 1900 through 1967, instead of "CAT" use the
abbreviation "AST", the abbreviation commonly used at the time
(Atlantic Standard Time had not been standardized yet). Use "AWT"
and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
Use "CST" and "CDT" instead of invented abbreviations for Macau
before 1999 and Taiwan before 1938, and use "JST" instead of the
invented abbreviation "JCST" for Japan and Korea before 1938.
Change to database entry category
Move the Pacific/Johnston link from 'australasia' to 'backward',
since Johnston is now uninhabited.
Changes to code
zic no longer mishandles some transitions in January 2038 when it
attempts to work around Qt bug 53071. This fixes a bug affecting
Pacific/Tongatapu that was introduced in zic 2016e. localtime.c
now contains a workaround, useful when loading a file generated by
a buggy zic. (Problem and localtime.c fix reported by Bradley
White.)
zdump -i now outputs non-hour numeric time zone abbreviations
without a colon, e.g., "+0530" rather than "+05:30". This agrees
with zic %z and with common practice, and simplifies auditing of
zdump output.
zdump is now buildable again with -DUSE_LTZ=0.
(Problem reported by Joseph Myers.)
zdump.c now always includes private.h, to avoid code duplication
with private.h. (Problem reported by Kees Dekker.)
localtime.c no longer mishandles early or late timestamps
when TZ is set to a POSIX-style string that specifies DST.
(Problem reported by Kees Dekker.)
date and strftime now cause %z to generate "-0000" instead of
"+0000" when the UT offset is zero and the time zone abbreviation
begins with "-".
Changes to documentation and commentary
The 'Theory' file now better documents choice of historical time
zone abbreviations. (Problems reported by Michael Deckers.)
tz-link.htm now covers leap smearing, which is popular in clouds.
Release 2016j - 2016-11-22 23:17:13 -0800
Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
Changes to future time stamps
Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
This hives off a new zone Europe/Saratov from Europe/Volgograd.
(Thanks to Yuri Konotopov and Stepan Golosunov.)
Changes to past time stamps
The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
1999, not fall 1994. (Thanks to Stepan Golosunov.)
Changes to past time zone abbreviations
Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
summer time before 1948. The old use of "EET" was a typo.
Changes to code
zic no longer mishandles file systems that lack hard links, fixing
bugs introduced in 2016g. (Problems reported by Tom Lane.)
Also, when the destination already contains symbolic links, zic
should now work better on systems where the 'link' system call
does not follow symbolic links.
Changes to documentation and commentary
tz-link.htm now documents the relationship between release version
numbers and development-repository commit tags. (Suggested by
Paul Koning.)
The 'Theory' file now documents UT.
iso3166.tab now accents "Curaçao", and commentary now mentions
the names "Cabo Verde" and "Czechia". (Thanks to Jiří Boháč.)
Release 2016i - 2016-11-01 23:19:52 -0700
Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
reintroduces DST on 2016-11-06.
Changes to future time stamps
Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
2017-01-15 at 03:00. Assume future observances in Tonga will be
from the first Sunday in November through the third Sunday in
January, like Fiji. (Thanks to Pulu ʻAnau.) Switch to numeric
time zone abbreviations for this zone.
Changes to past and future time stamps
Northern Cyprus is now +03 year round, causing a split in Cyprus
time zones starting 2016-10-30 at 04:00. This creates a zone
Asia/Famagusta. (Thanks to Even Scharning and Matt Johnson.)
Antarctica/Casey switched from +08 to +11 on 2016-10-22.
(Thanks to Steffen Thorsen.)
Changes to past time stamps
Several corrections were made for pre-1975 time stamps in Italy.
These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
Europe/Vatican.
First, the 1893-11-01 00:00 transition in Italy used the new UT
offset (+01), not the old (+00:49:56). (Thanks to Michael
Deckers.)
Second, rules for daylight saving in Italy were changed to agree
with Italy's National Institute of Metrological Research (INRiM)
except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
Inglis, and Michael Deckers):
The 1916-06-03 transition was at 24:00, not 00:00.
The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
00:00, not 01:00.
The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
01:00.
The 1944-09-17 transition was at 03:00, not 01:00. This
particular change is taken from Italian law as INRiM's table,
(which says 02:00) appears to have a typo here. Also, keep the
1944-04-03 transition for Europe/Rome, as Rome was controlled by
Germany then.
The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
not 00:00.
Changes to code
The code should now be buildable on AmigaOS merely by setting the
appropriate Makefile variables. (From a patch by Carsten Larsen.)
Release 2016h - 2016-10-19 23:17:57 -0700
Changes to future time stamps
Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
2016-10-21 at 00:00. (Thanks to Sharef Mustafa.) Predict that
future fall transitions will be on the last Saturday of October
at 01:00, which is consistent with predicted spring transitions
on the last Saturday of March. (Thanks to Tim Parenti.)
Changes to past time stamps
In Turkey, transitions in 1986-1990 were at 01:00 standard time
not at 02:00, and the spring 1994 transition was on March 20, not
March 27. (Thanks to Kıvanç Yazan.)
Changes to past and future time zone abbreviations
Asia/Colombo now uses numeric time zone abbreviations like "+0530"
instead of alphabetic ones like "IST" and "LKT". Various
English-language sources use "IST", "LKT" and "SLST", with no
working consensus. (Usage of "SLST" mentioned by Sadika
Sumanapala.)
Changes to code
zic no longer mishandles relativizing file names when creating
symbolic links like /etc/localtime, when these symbolic links
are outside the usual directory hierarchy. This fixes a bug
introduced in 2016g. (Problem reported by Andreas Stieger.)
Changes to build procedure
New rules 'traditional_tarballs' and 'traditional_signatures' for
building just the traditional-format distribution. (Requested by
Deborah Goldsmith.)
The file 'version' is now put into the tzdata tarball too.
(Requested by Howard Hinnant.)
Changes to documentation and commentary
The 'Theory' file now has a section on interface stability.
(Requested by Paul Koning.) It also mentions features like
tm_zone and localtime_rz that have long been supported by the
reference code.
tz-link.htm has improved coverage of time zone boundaries suitable
for geolocation. (Thanks to heads-ups from Evan Siroky and Matt
Johnson.)
The US commentary now mentions Allen and the "day of two noons".
The Fiji commentary mentions the government's 2016-10-03 press
release. (Thanks to Raymond Kumar.)
Release 2016g - 2016-09-13 08:56:38 -0700
Changes to future time stamps
Turkey switched from EET/EEST (+02/+03) to permanent +03,
effective 2016-09-07. (Thanks to Burak AYDIN.) Use "+03" rather
than an invented abbreviation for the new time.
New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
(Thanks to Tim Parenti.)
Changes to past time stamps
For America/Los_Angeles, spring-forward transition times have been
corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
1950-1966.
For zones using Soviet time on 1919-07-01, transitions to UT-based
time were at 00:00 UT, not at 02:00 local time. The affected
zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
Europe/Ulyanovsk. (Thanks to Alexander Belopolsky.)
Changes to past and future time zone abbreviations
The Factory zone now uses the time zone abbreviation -00 instead
of a long English-language string, as -00 is now the normal way to
represent an undefined time zone.
Several zones in Antarctica and the former Soviet Union, along
with zones intended for ships at sea that cannot use POSIX TZ
strings, now use numeric time zone abbreviations instead of
invented or obsolete alphanumeric abbreviations. The affected
zones are Antarctica/Casey, Antarctica/Davis,
Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
Europe/Minsk, Europe/Samara, Europe/Volgograd, and
Indian/Kerguelen. For Europe/Moscow the invented abbreviation MSM
was replaced by +05, whereas MSK and MSD were kept as they are not
our invention and are widely used.
Changes to zone names
Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
(Thanks to David Massoud.)
Changes to code
zic no longer generates binary files containing POSIX TZ-like
strings that disagree with the local time type after the last
explicit transition in the data. This fixes a bug with
Africa/Casablanca and Africa/El_Aaiun in some year-2037 time
stamps on the reference platform. (Thanks to Alexander Belopolsky
for reporting the bug and suggesting a way forward.)
If the installed localtime and/or posixrules files are symbolic
links, zic now keeps them symbolic links when updating them, for
compatibility with platforms like OpenSUSE where other programs
configure these files as symlinks.
zic now avoids hard linking to symbolic links, avoids some
unnecessary mkdir and stat system calls, and uses shorter file
names internally.
zdump has a new -i option to generate transitions in a
more-compact but still human-readable format. This option is
experimental, and the output format may change in future versions.
(Thanks to Jon Skeet for suggesting that an option was needed,
and thanks to Tim Parenti and Chris Rovick for further comments.)
Changes to build procedure
An experimental distribution format is available, in addition
to the traditional format which will continue to be distributed.
The new format is a tarball tzdb-VERSION.tar.lz with signature
file tzdb-VERSION.tar.lz.asc. It unpacks to a top-level directory
tzdb-VERSION containing the code and data of the traditional
two-tarball format, along with extra data that may be useful.
(Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
for comments about the experimental format.)
The release version number is now more accurate in the usual case
where releases are built from a Git repository. For example, if
23 commits and some working-file changes have been made since
release 2016g, the version number is now something like
'2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
Tagged releases use the same version number format as before,
e.g., '2016g'. To support the more-accurate version number, its
specification has moved from a line in the Makefile to a new
source file 'version'.
The experimental distribution contains a file to2050.tzs that
contains what should be the output of 'zdump -i -c 2050' on
primary zones. If this file is available, 'make check' now checks
that zdump generates this output.
'make check_web' now works on Fedora-like distributions.
Changes to documentation and commentary
tzfile.5 now documents the new restriction on POSIX TZ-like
strings that is now implemented by zic.
Comments now cite URLs for some 1917-1921 Russian DST decrees.
(Thanks to Alexander Belopolsky.)
tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
(thanks to Meno Hochschild) and ThreeTen-Extra, and its
description of Java 8 has been brought up to date (thanks to
Stephen Colebourne). Its description of local time on Mars has
been updated to match current practice, and URLs have been updated
and some obsolete ones removed.
Release 2016f - 2016-07-05 16:26:51 +0200
Changes affecting future time stamps
The Egyptian government changed its mind on short notice, and
Africa/Cairo will not introduce DST starting 2016-07-07 after all.
(Thanks to Mina Samuel.)
Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
(Thanks to Stepan Golosunov.)
Changes to past and future time stamps
Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
abbreviations instead of invented ones.
Changes affecting past time stamps
Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
(Thanks to Stepan Golosunov.)
Release 2016e - 2016-06-14 08:46:16 -0700
Changes affecting future time stamps
Africa/Cairo observes DST in 2016 from July 7 to the end of October.
Guess October 27 and 24:00 transitions. (Thanks to Steffen Thorsen.)
For future years, guess April's last Thursday to October's last
Thursday except for Ramadan.
Changes affecting past time stamps
Locations while uninhabited now use '-00', not 'zzz', as a
placeholder time zone abbreviation. This is inspired by Internet
RFC 3339 and is more consistent with numeric time zone
abbreviations already used elsewhere. The change affects several
arctic and antarctic locations, e.g., America/Cambridge_Bay before
1920 and Antarctica/Troll before 2005.
Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
at 03:00, not 23:00 the previous day. (Thanks to Michael Deckers.)
Changes to code
zic now outputs a dummy transition at time 2**31 - 1 in zones
whose POSIX-style TZ strings contain a '<'. This mostly works
around Qt bug 53071 <https://bugreports.qt.io/browse/QTBUG-53071>.
(Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
Changes affecting documentation and commentary
tz-link.htm says why governments should give plenty of notice for
time zone or DST changes, and refers to Matt Johnson's blog post.
tz-link.htm mentions Tzdata for Elixir. (Thanks to Matt Johnson.)
Release 2016d - 2016-04-17 22:50:29 -0700
Changes affecting future time stamps
America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
(Thanks to Alexander Krivenyshev for the heads-up.)
Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
(Thanks to Alexander Krivenyshev and Matt Johnson.)
New zone Asia/Tomsk, split off from Asia/Novosibirsk. It covers
Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
at 02:00. (Thanks to Stepan Golosunov.)
Changes affecting past time stamps
New zone Europe/Kirov, split off from Europe/Volgograd. It covers
Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
the same change. (Thanks to Stepan Golosunov.)
Russia and nearby locations had daylight-saving transitions on
1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
1992-03-28 at 23:00 and 1992-09-26 at 23:00. (Thanks to Stepan
Golosunov.)
Many corrections to historical time in Kazakhstan from 1991
through 2005. (Thanks to Stepan Golosunov.) Replace Kazakhstan's
invented time zone abbreviations with numeric abbreviations.
Changes to commentary
Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
Release 2016c - 2016-03-23 00:51:27 -0700
Changes affecting future time stamps
Azerbaijan no longer observes DST. (Thanks to Steffen Thorsen.)
Chile reverts from permanent to seasonal DST. (Thanks to Juan
Correa for the heads-up, and to Tim Parenti for corrections.)
Guess that future transitions are August's and May's second
Saturdays at 24:00 mainland time. Also, call the period from
2014-09-07 through 2016-05-14 daylight saving time instead of
standard time, as that seems more appropriate now.
Changes affecting past time stamps
Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
+02/+03 on 1989-03-26, not 1991-03-31. Europe/Volgograd changed
from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
(Thanks to Stepan Golosunov.)
Changes to commentary
Several updates and URLs for historical and proposed Russian changes.
(Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
Release 2016b - 2016-03-12 17:30:14 -0800
Compatibility note
Starting with release 2016b, some data entries cause zic implementations
derived from tz releases 2005j through 2015e to issue warnings like
"time zone abbreviation differs from POSIX standard (+03)".
These warnings should not otherwise affect zic's output and can safely be
ignored on today's platforms, as the warnings refer to a restriction in
POSIX.1-1988 that was removed in POSIX.1-2001. One way to suppress the
warnings is to upgrade to zic derived from tz releases 2015f and later.
Changes affecting future time stamps
New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
2016-03-27 at 02:00 local time. They need distinct zones since their
post-1970 histories disagree. New zone Asia/Barnaul for Altai Krai and
Altai Republic, Russia, which will switch from +06 to +07 on the same date
and local time. The Astrakhan change is already official; the others have
passed the first reading in the State Duma and are extremely likely.
Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
(Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
and Stepan Golosunov for followup.)
As a trial of a new system that needs less information to be made up,
the new zones use numeric time zone abbreviations like "+04"
instead of invented abbreviations like "ASTT".
Haiti will not observe DST in 2016. (Thanks to Jean Antoine via
Steffen Thorsen.)
Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
(Thanks to Hannah Kreitem.) Guess future transitions will be March's last
Saturday at 01:00, not March's last Friday at 24:00.
Changes affecting past time stamps
Europe/Chisinau observed DST during 1990, and switched from +04 to
+03 at 1990-05-06 02:00, instead of switching from +03 to +02.
(Thanks to Stepan Golosunov.)
1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
KUYT/KUYST. (Thanks to Stepan Golosunov.)
Changes to code
tzselect's diagnostics and checking, and checktab.awk's checking,
have been improved. (Thanks to J William Piggott.)
tzcode now builds under MinGW. (Thanks to Ian Abbott and Esben Haabendal.)
tzselect now tests Julian-date TZ settings more accurately.
(Thanks to J William Piggott.)
Changes to commentary
Comments in zone tables have been improved. (Thanks to J William Piggott.)
tzselect again limits its menu comments so that menus fit on a
24x80 alphanumeric display.
A new web page tz-how-to.html. (Thanks to Bill Seymour.)
In the Theory file, the description of possible time zone abbreviations in
tzdata has been cleaned up, as the old description was unclear and
inconsistent. (Thanks to Alain Mouette for reporting the problem.)
Release 2016a - 2016-01-26 23:28:02 -0800
Changes affecting future time stamps
America/Cayman will not observe daylight saving this year after all.
Revert our guess that it would. (Thanks to Matt Johnson.)
Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
(Thanks to Alexander Krivenyshev.)
Asia/Tehran now has DST predictions for the year 2038 and later,
to be March 21 00:00 to September 21 00:00. This is likely better
than predicting no DST, albeit off by a day every now and then.
Changes affecting past and future time stamps
America/Metlakatla switched from PST all year to AKST/AKDT on
2015-11-01 at 02:00. (Thanks to Steffen Thorsen.)
America/Santa_Isabel has been removed, and replaced with a
backward compatibility link to America/Tijuana. Its contents were
apparently based on a misreading of Mexican legislation.
Changes affecting past time stamps
Asia/Karachi's two transition times in 2002 were off by a minute.
(Thanks to Matt Johnson.)
Changes affecting build procedure
An installer can now combine leap seconds with use of the backzone file,
e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
The old 'make posix_packrat' rule is now marked as obsolescent.
(Thanks to Ian Abbott for an initial implementation.)
Changes affecting documentation and commentary
A new file LICENSE makes it easier to see that the code and data
are mostly public-domain. (Thanks to James Knight.) The three
non-public-domain files now use the current (3-clause) BSD license
instead of older versions of that license.
tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
on editing tz source files (with a mention of Sublime zoneinfo,
thanks to Gilmore Davidson).
The Theory and asia files now mention the 2015 book "The Global
Transformation of Time, 1870-1950", and cite a couple of reviews.
The America/Chicago entry now documents the informal use of US
central time in Fort Pierre, South Dakota. (Thanks to Rick
McDermid, Matt Johnson, and Steve Jones.)
Release 2015g - 2015-10-01 00:39:51 -0700
Changes affecting future time stamps
Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
(Thanks to Fatih.)
Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
(Thanks to Alexander Krivenyshev.)
Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
(Thanks to Ken Rylander.)
Fort Nelson, British Columbia will not fall back on 2015-11-01. It has
effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
New zone America/Fort_Nelson. (Thanks to Matt Johnson.)
Changes affecting past time stamps
Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
Changes affecting code
localtime no longer mishandles America/Anchorage after 2037.
(Thanks to Bradley White for reporting the bug.)
On hosts with signed 32-bit time_t, localtime no longer mishandles
Pacific/Fiji after 2038-01-16 14:00 UTC.
The localtime module allows the variables 'timezone', 'daylight',
and 'altzone' to be in common storage shared with other modules,
and declares them in case the system <time.h> does not.
(Problems reported by Kees Dekker.)
On platforms with tm_zone, strftime.c now assumes it is not NULL.
This simplifies the code and is consistent with zdump.c.
(Problem reported by Christos Zoulas.)
Changes affecting documentation
The tzfile man page now documents that transition times denote the
starts (not the ends) of the corresponding time periods.
(Ambiguity reported by Bill Seymour.)
Release 2015f - 2015-08-10 18:06:56 -0700
Changes affecting future time stamps
North Korea switches to +0830 on 2015-08-15. (Thanks to Steffen Thorsen.)
The abbreviation remains "KST". (Thanks to Robert Elz.)
Uruguay no longer observes DST. (Thanks to Steffen Thorsen
and Pablo Camargo.)
Changes affecting past and future time stamps
Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
(Thanks to Roman Tudos.)
Changes affecting data format and code
zic's '-y YEARISTYPE' option is no longer documented. The TYPE
field of a Rule line should now be '-'; the old values 'even',
'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
Although the implementation has not changed, these features do not
work in the default installation, they are not used in the data,
and they are now considered obsolescent.
zic now checks that two rules don't take effect at the same time.
(Thanks to Jon Skeet and Arthur David Olson.) Constraints on
simultaneity are now documented.
The two characters '%z' in a zone format now stand for the UTC
offset, e.g., '-07' for seven hours behind UTC and '+0530' for
five hours and thirty minutes ahead. This better supports time
zone abbreviations conforming to POSIX.1-2001 and later.
Changes affecting installed data files
Comments for America/Halifax and America/Glace_Bay have been improved.
(Thanks to Brian Inglis.)
Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
Europe/Sofia, and Europe/Tallinn. This yields slightly smaller
installed data files for Europe/Simferopol and Europe/Tallinn.
It does not affect timestamps. (Thanks to Howard Hinnant.)
Changes affecting code
zdump and zic no longer warn about valid time zone abbreviations
like '-05'.
Some Visual Studio 2013 warnings have been suppressed.
(Thanks to Kees Dekker.)
'date' no longer sets the time of day and its -a, -d, -n and -t
options have been removed. Long obsolescent, the implementation
of these features had porting problems. Builders no longer need
to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
(Thanks to Kees Dekker for pointing out the problem.)
Changes affecting documentation
The Theory file mentions naming issues earlier, as these seem to be
poorly publicized (thanks to Gilmore Davidson for reporting the problem).
tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
Mention that Herbert Samuel introduced the term "Summer Time".
Release 2015e - 2015-06-13 10:56:02 -0700
Changes affecting future time stamps
Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
not 06-13 and 07-18 as we had guessed. (Thanks to Milamber.)
Assume Cayman Islands will observe DST starting next year, using US rules.
Although it isn't guaranteed, it is the most likely.
Changes affecting data format
The file 'iso3166.tab' now uses UTF-8, so that its entries can better
spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
Changes affecting code
When displaying data, tzselect converts it to the current locale's
encoding if the iconv command works. (Problem reported by random832.)
tzselect no longer mishandles Dominica, fixing a bug introduced
in Release 2014f. (Problem reported by Owen Leibman.)
zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
This fixes a bug introduced in Release 2014f.
(Problem reported by Leonardo Chiquitto.)
Release 2015d - 2015-04-24 08:09:46 -0700
Changes affecting future time stamps
Egypt will not observe DST in 2015 and will consider canceling it
permanently. For now, assume no DST indefinitely.
(Thanks to Ahmed Nazmy and Tim Parenti.)
Changes affecting past time stamps
America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
1966-07-01. Also, Yukon's time zone history is documented better.
(Thanks to Brian Inglis and Dennis Ferguson.)
Change affecting past and future time zone abbreviations
The abbreviations for Hawaii-Aleutian standard and daylight times
have been changed from HAST/HADT to HST/HDT, as per US Government
Printing Office style. This affects only America/Adak since 1983,
as America/Honolulu was already using the new style.
Changes affecting code
zic has some minor performance improvements.
Release 2015c - 2015-04-11 08:55:55 -0700
Changes affecting future time stamps
Egypt's spring-forward transition is at 24:00 on April's last Thursday,
not 00:00 on April's last Friday. 2015's transition will therefore be on
Thursday, April 30 at 24:00, not Friday, April 24 at 00:00. Similar fixes
apply to 2026, 2037, 2043, etc. (Thanks to Steffen Thorsen.)
Changes affecting past time stamps
The following changes affect some pre-1991 Chile-related time stamps
in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
The 1910 transition was January 10, not January 1.
The 1918 transition was September 10, not September 1.
The UT -04 time observed from 1932 to 1942 is now considered to
be standard time, not year-round DST.
Santiago observed DST (UT -03) from 1946-07-15 through
1946-08-31, then reverted to standard time, then switched to -05
on 1947-04-01.
Assume transitions before 1968 were at 00:00, since we have no data
saying otherwise.
The spring 1988 transition was 1988-10-09, not 1988-10-02.
The fall 1990 transition was 1990-03-11, not 1990-03-18.