IANA 2026d

Author: stub42

tz/CONTRIBUTING

@@ -22,7 +22,7 @@ To email small changes, please run a POSIX shell command like
 For more-elaborate or possibly controversial changes,
 such as renaming, adding or removing zones, please read
 “Theory and pragmatics of the tz code and data”
-<https://www.iana.org/time-zones/repository/theory.html>.
+<https://data.iana.org/time-zones/theory.html>
 It is also good to browse the mailing list archives
 <https://lists.iana.org/hyperkitty/list/tz@iana.org/>
 for examples of patches that tend to work well.

tz/Makefile

@@ -172,9 +172,9 @@ EXPIRES_LINE=	0
 
 TZDATA_TEXT=	leapseconds tzdata.zi
 
-# For backward-compatibility links for old zone names, use
+# For backward-compatibility links and zones for old names, use
 #	BACKWARD=	backward
-# To omit these links, use
+# To omit these links and zones, use
 #	BACKWARD=
 
 BACKWARD=	backward
@@ -574,7 +574,7 @@ SAFE_CHAR=	'[]'$(SAFE_CHARSET)'-]'
 # These non-alphabetic, non-ASCII printable characters are
 # used in commentary or in generated *.txt files
 # and are not likely to cause confusion.
-UNUSUAL_OK_CHARSET= §«°±»½¾×–‘’“”•→−≤★⟨⟩⯪
+UNUSUAL_OK_CHARSET= §«°±»½¾¿×–‘’“”•→−≤★⟨⟩⯪
 
 # Put this in a bracket expression to match spaces.
 s = [:space:]
@@ -922,7 +922,7 @@ check_mild: check_web check_zishrink \
 UTF8_LOCALE_MISSING = \
   { test ! '$(UTF8_LOCALE)' \
     || ! printf 'A\304\200B\n' \
-         | LC_ALL='$(UTF8_LOCALE)' grep -q '^A.B$$' >/dev/null 2>&1 \
+         | LC_ALL='$(UTF8_LOCALE)' grep -q '^A[[:alpha:]]B$$' >/dev/null 2>&1 \
     || { export LC_ALL='$(UTF8_LOCALE)'; false; }; }
 
 character-set.ck: $(ENCHILADA)
@@ -1006,19 +1006,24 @@ now.ck: checknow.awk date tzdata.zi zdump zic zone1970.tab zonenow.tab
 		now=$(CHECK_NOW_TIMESTAMP) && \
 		  future=$$(($(CHECK_NOW_FUTURE_SECS) + $$now)) && \
 		  ./zdump -i -t $$now,$$future \
-		     $$(find "$$PWD/$@d"/????*/ -type f) \
+		     $$(find "$$PWD/$@d"/????*/ -type f -o -type l) \
 		     >$@d/zdump-now.tab && \
 		  ./zdump -i -t 0,$$future \
 		     $$(find "$$PWD/$@d" -name Etc -prune \
-			  -o -type f ! -name '*.tab' -print) \
+			  -o \( -type f -o -type l \) ! -name '*.tab' -print) \
 		     >$@d/zdump-1970.tab && \
 		$(AWK) \
 		  -v now=$$now \
 		  -v now_out=$@.out \
 		  -v zdump_table=$@d/zdump-now.tab \
 		  -f checknow.awk zonenow.tab
 		$(AWK) \
-		  'BEGIN {print "-\t-\tUTC"} /^Zone/ {print "-\t-\t" $$2}' \
+		  'BEGIN { \
+		     SysVzone["EST5EDT"] = 1; SysVzone["CST6CDT"] = 1; \
+		     SysVzone["MST7MDT"] = 1; SysVzone["PST8PDT"] = 1; \
+		     print "-\t-\tUTC" \
+		   } \
+		   $$1 == "Zone" && !SysVzone[$$2] {print "-\t-\t" $$2}' \
 		  $(PRIMARY_YDATA) backward factory | \
 		 $(AWK) \
 		   -v zdump_table=$@d/zdump-1970.tab \

tz/NEWS

@@ -1,5 +1,87 @@
 News for the tz database
 
+Release 2026d - 2026-09-11 15:21:07 -0700
+
+  Briefly:
+    Canada’s Northwest Territories moved to permanent -06 on 2026-08-21.
+    Obsolescent settings like TZ="EST5EDT" now conform better to POSIX.
+    Fix security, performance and porting bugs in zic and localtime.
+
+  Changes to future timestamps
+
+    Canada’s Northwest Territories will not fall back on 2026-11-01
+    and will stay on -06 year-round, matching Alberta’s recent change.
+    Model this with its traditional abbreviation CST.  Although the
+    change to permanent -06 legally took place on 2026-08-21,
+    temporarily model the change to occur on 2026-11-01 at 02:00
+    for the same reason as other recent temporary hacks.  (Caution:
+    see “NOTE FOR 2026b TEMPORARY HACK FOR CLDR AND CANADA” below.)
+    This affects only America/Inuvik as the rest of the territory is
+    covered by America/Edmonton, for which the equivalent change was
+    released in 2026c.
+
+  Changes to past timestamps
+
+    Colombia’s 1992-05-02 spring forward was at 00:00, not 24:00.
+
+    Iran’s 1979-05-26 spring forward was at 00:00, not 24:00.
+    (Thanks to N.F. Hase.)
+
+    The backward-compatibility names EST5EDT, CST6CDT, MST7MDT, and
+    PST8PDT now conform better to POSIX.  For example, EST5EDT now
+    always uses the abbreviation "EST" for standard time (now always 5
+    hours behind UT) and "EDT" for daylight saving time, whereas it
+    formerly had different UT offsets before standard time was
+    introduced and sometimes used abbreviations like "LMT", "EWT" and
+    "EPT", all contrary to POSIX.  Also, though not required by POSIX
+    these names now use US federal rules rather than rules of places
+    like New York, reverting to 2024a behavior.  This change affects
+    only timestamps before 1966-10-30 at 01:00 standard time.
+
+  Other data changes
+
+    The temporary hacks used for North American timekeeping changes
+    now work around a libstdc++ std::chrono bug in GCC 14.1-14.4,
+    15.1-15.2, and 16.1; see GCC bug 124851.  This data change does
+    not affect TZif files or timestamps.  The change does not work
+    around the related but less serious GCC bugs 116110 and 124513.
+    These GCC bugs are all fixed in GCC 16.2.
+
+  Changes to code
+
+    zic now rejects Link targets that would have invalid names, and
+    more efficiently processes Expires, Leap and Rule lines with years
+    far in the past or future.  (Thanks to Darren Carreras.)
+
+    zic now ports to systems that report lack of link support via
+    EINVAL, ENOSYS or EPERM errno values. (Thanks to Tom Lane.)
+
+    When tzset and related functions encounter a TZif file that is too
+    large for them, they now consistently fail instead of sometimes
+    silently ignoring excess parts of the file.
+
+    localtime-related functions no longer mishandle extreme timestamps
+    when given TZif files holding some unlikely timezone histories.
+    (Problem reported by David Sarkisyan.)
+
+    localtime-related functions no longer check the values of TZif
+    files’ standard/wall and UT/local indicators, which these
+    functions have not used since 2026a’s removal of the old
+    posixrules feature.
+
+    tzcode has been ported to Haiku.
+
+    localtime.c now works again by default on AIX and DragonFly BSD.
+
+    zic now rejects ‘:’ and ‘\’ in Zone and Link names when running on
+    Microsoft Windows.  (Problem reported by David Diaz.)
+
+  Changes to documentation
+
+    URLs for release tarballs in tz-link.html have been updated to
+    reflect their new canonical URLs on data.iana.org.
+
+
 Release 2026c - 2026-07-08 10:23:58 -0700
 
   Briefly:
@@ -15,7 +97,13 @@ Release 2026c - 2026-07-08 10:23:58 -0700
     CST.  Although the change to permanent -06 legally took place on
     2026-06-18, temporarily model the change to occur on 2026-11-01 at
     02:00 instead, for the same reason we introduced a similarly
-    temporary hack for British Columbia in 2026b.
+    temporary hack for British Columbia in 2026b.  (Caution: see
+    “NOTE FOR 2026b TEMPORARY HACK FOR CLDR AND CANADA” below.)
+
+      As the change affects both America/Edmonton and its backward
+      compatibility link, the obsolescent setting TZ="Canada/Mountain"
+      will now use the abbreviation CST for affected timestamps,
+      akin to TZ="Canada/Pacific" behavior introduced in 2026b.
 
       Although another TZDB release will likely be needed soon because
       Northwest Territories will likely follow Alberta, the legal
@@ -67,6 +155,7 @@ Release 2026b - 2026-04-22 23:06:43 -0700
 
   Briefly:
     British Columbia moved to permanent -07 on 2026-03-09.
+    zic no longer mishandles a last transition to a new time type.
     Some more overflow bugs have been fixed in zic.
 
   Changes to future timestamps
@@ -79,9 +168,33 @@ Release 2026b - 2026-04-22 23:06:43 -0700
     limitation in CLDR 48.1 (2026-01-08).  This temporary hack is
     planned to be removed after CLDR is fixed.
 
+      To match longstanding practice for -07 standard time in North
+      America, such as for America/Dawson, America/Dawson_Creek,
+      America/Fort_Nelson and America/Whitehorse, affected BC
+      timestamps use the abbreviation MST.  As the change affects both
+      America/Vancouver and its backward compatibility link, the
+      obsolescent setting TZ="Canada/Pacific" will now use the
+      abbreviation MST.  Future TZDB releases may change the
+      abbreviation if something else becomes popular across areas
+      observing -07, and may change it to "-07" if no alphabetic
+      consensus emerges.
+
   Changes to code
 
     zic no longer mishandles a last transition to a new time type.
+    NOTE FOR 2026b TEMPORARY HACK FOR CLDR AND CANADA:
+    This zic fix is needed for the temporary hack (mentioned above)
+    that works around the Canadian timekeeping bug in Unicode CLDR.
+    Without the fix, the temporary hack causes zic versions 2023d
+    through 2026a, in their default mode that generates slim output,
+    to generate a TZif file that violates Internet RFC 9636 §3.3.
+    The buggy file in turn causes some TZif readers, including tzcode
+    itself, to ignore America/Vancouver’s 2026-11-01 02:00 transition
+    from PDT (tm_isdst=1) to MST (tm_isdst=0).  Although the buggy
+    file does not cause any known TZif reader to mishandle UT offsets,
+    caution is advised when using zic 2023d through 2026a to compile
+    data from more-recent tz releases.  To work around this problem
+    when using these older zic versions, use ‘zic -b fat’.
 
     zic no longer overflows a buffer when generating a TZ string like
     "PST-167:59:58PDT-167:59:59,M11.5.6/-167:59:59,M12.5.6/-167:59:59",

tz/README

@@ -10,7 +10,7 @@ locations around the globe.  It is updated periodically to reflect
 changes made by political bodies to time zone boundaries, UTC offsets,
 and daylight-saving rules.
 
-See <https://www.iana.org/time-zones/repository/tz-link.html> or the
+See <https://data.iana.org/time-zones/tz-link.html> or the
 file tz-link.html for how to acquire the code and data.
 
 Once acquired, read the leading comments in the file ‘Makefile’

tz/asia

@@ -1544,9 +1544,21 @@ Zone Asia/Jayapura	9:22:48 -	LMT	1932 Nov
 # leap year calculation involved.  There has never been any serious
 # plan to change that law....
 #
-# From Paul Eggert (2022-06-30):
-# Go with Pournader for 1935 through spring 1979, and for timestamps
-# after August 1991; go with with Shanks & Pottenger for other timestamps.
+# From N.F. Hase (2026-07-26):
+# Ettela'at (Tehran daily) printed a daily panel headed "taqvim-e
+# Ettela'at / sa'at-ha-ye shar'i", attributed to Dr. Riyazi Kermani.
+# Each panel gives today's maghrib followed by fajr, sunrise, solar noon
+# and maghrib for the next day, together with the Iranian, Hijri and
+# Gregorian dates.... 26 May 1979 (5 Khordād 1358)
+# https://commons.wikimedia.org/wiki/File:Ettelaat13580305.pdf
+# ... That also matches Movahedi's wording, that the government
+# returned to DST on 26 May, and the note in the 2022 thread that the
+# change was announced one day in advance on 25 May.
+#
+# From Paul Eggert (2026-07-27):
+# Go with Pournader for 1935 through spring 1979 (with the last
+# transition clarified by Hase), and for timestamps after August 1991;
+# go with Shanks & Pottenger for other timestamps.
 # Go with Santoni's citation of the UIT for fall 1977, as 20 October 1977
 # is 28 Mehr 1356, consistent with the "Mehr" in Pournader's source.
 # Assume that the UIT's "1930" is UTC, i.e., 24:00 local time.
@@ -1591,13 +1603,13 @@ Zone Asia/Jayapura	9:22:48 -	LMT	1932 Nov
 #
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # Work around a bug in zic 2022a and earlier.
-Rule	Iran	1910	only	-	Jan	 1	00:00	0	-
+Rule	Iran	1910	only	-	Jan	 1	 0:00	0	-
 #
 Rule	Iran	1977	only	-	Mar	21	23:00	1:00	-
 Rule	Iran	1977	only	-	Oct	20	24:00	0	-
 Rule	Iran	1978	only	-	Mar	24	24:00	1:00	-
-Rule	Iran	1978	only	-	Aug	 5	01:00	0	-
-Rule	Iran	1979	only	-	May	26	24:00	1:00	-
+Rule	Iran	1978	only	-	Aug	 5	 1:00	0	-
+Rule	Iran	1979	only	-	May	26	 0:00	1:00	-
 Rule	Iran	1979	only	-	Sep	18	24:00	0	-
 Rule	Iran	1980	only	-	Mar	20	24:00	1:00	-
 Rule	Iran	1980	only	-	Sep	22	24:00	0	-

tz/backward

@@ -15,7 +15,8 @@
 # typically use this file for backward compatibility.
 
 # This file is divided into sections, one for each major reason for a
-# backward compatibility link.  Each section is sorted by link name.
+# backward compatibility link or zone.  Each section of links is
+# sorted by name.
 
 # A "#= TARGET1" comment labels each link inserted only because some
 # .zi parsers (including tzcode through 2022e) mishandle links to links.
@@ -46,7 +47,6 @@ Link	America/Noronha		Brazil/DeNoronha
 Link	America/Sao_Paulo	Brazil/East
 Link	America/Manaus		Brazil/West
 Link	Europe/Brussels		CET
-Link	America/Chicago		CST6CDT
 Link	America/Halifax		Canada/Atlantic
 Link	America/Winnipeg	Canada/Central
 # This line is commented out, as the name exceeded the 14-character limit
@@ -63,7 +63,6 @@ Link	Pacific/Easter		Chile/EasterIsland
 Link	America/Havana		Cuba
 Link	Europe/Athens		EET
 Link	America/Panama		EST
-Link	America/New_York	EST5EDT
 Link	Africa/Cairo		Egypt
 Link	Europe/Dublin		Eire
 # Vanguard section, for most .zi parsers.
@@ -104,7 +103,6 @@ Link	Pacific/Kwajalein	Kwajalein
 Link	Africa/Tripoli		Libya
 Link	Europe/Brussels		MET
 Link	America/Phoenix		MST
-Link	America/Denver		MST7MDT
 Link	America/Tijuana		Mexico/BajaNorte
 Link	America/Mazatlan	Mexico/BajaSur
 Link	America/Mexico_City	Mexico/General
@@ -326,6 +324,52 @@ Link	Europe/Kyiv		Europe/Kiev
 # However, for various reasons many users expect to find it under Europe.
 Link	Asia/Nicosia		Europe/Nicosia
 Link	Pacific/Honolulu	HST
-Link	America/Los_Angeles	PST8PDT
 Link	Pacific/Guadalcanal	Pacific/Ponape	#= Pacific/Pohnpei
 Link	Pacific/Port_Moresby	Pacific/Truk	#= Pacific/Chuuk
+
+
+# The backward-compatibility zones PST8PDT, MST7MDT, CST6CDT, and EST5EDT
+
+# Near-copy of US rules in the northamerica file,
+# so that this file can be compiled separately.
+# To conform to POSIX, this copy uses D instead of W for War and P for Peace.
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
+Rule	USback	1918	1919	-	Mar	lastSun	2:00	1:00	D
+Rule	USback	1918	1919	-	Oct	lastSun	2:00	0	S
+Rule	USback	1942	only	-	Feb	9	2:00	1:00	D # War
+Rule	USback	1945	only	-	Aug	14	23:00u	1:00	D # Peace
+Rule	USback	1945	only	-	Sep	30	2:00	0	S
+Rule	USback	1967	2006	-	Oct	lastSun	2:00	0	S
+Rule	USback	1967	1973	-	Apr	lastSun	2:00	1:00	D
+Rule	USback	1974	only	-	Jan	6	2:00	1:00	D
+Rule	USback	1975	only	-	Feb	lastSun	2:00	1:00	D
+Rule	USback	1976	1986	-	Apr	lastSun	2:00	1:00	D
+Rule	USback	1987	2006	-	Apr	Sun>=1	2:00	1:00	D
+Rule	USback	2007	max	-	Mar	Sun>=8	2:00	1:00	D
+Rule	USback	2007	max	-	Nov	Sun>=1	2:00	0	S
+
+# From Arthur David Olson (2005-12-19):
+# We generate the files specified below to guard against old files with
+# obsolete information being left in the time zone binary directory.
+# We limit the list to names that have appeared in previous versions of
+# this time zone package.
+# We do these as separate Zones rather than as Links to avoid problems if
+# a particular place changes whether it observes DST.
+#
+# From Paul Eggert (2026-07-24):
+# These zones are for backward compatibility with Unix System V (1983).
+# They are ahistorical, in that they pretend standard time extends
+# backward indefinitely into the past.
+# They use USback (not US) rules so that they conform to POSIX instead
+# of using abbreviations like EWT for Eastern War Time during World War II.
+# The zones are here, not in the northamerica file, to lessen
+# confusion downstream by making it clear that the zones are present
+# only for backward compatibility.
+# New software should use settings like TZ='America/New_York' instead
+# of these backwards-compatibility zones.
+#
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
+Zone	PST8PDT		 -8:00	USback	P%sT
+Zone	MST7MDT		 -7:00	USback	M%sT
+Zone	CST6CDT		 -6:00	USback	C%sT
+Zone	EST5EDT		 -5:00	USback	E%sT

tz/backzone

@@ -927,9 +927,10 @@ Zone America/Tortola	-4:18:28 -	LMT	1911 Jul # Road Town
 			-4:00	-	AST
 
 # Yellowknife, Northwest Territories
-Zone America/Yellowknife 0	-	-00	1935 # Yellowknife founded?
-			-7:00	NT_YK	M%sT	1980
-			-7:00	Canada	M%sT
+# Commented out as too wrong to be useful.
+#Zone America/Yellowknife 0	-	-00	1935 # Yellowknife founded?
+#			-7:00	NT_YK	M%sT	1980
+#			-7:00	Canada	M%sT
 
 # Dumont d'Urville, Île des Pétrels, -6640+14001, since 1956-11
 # <https://en.wikipedia.org/wiki/Dumont_d'Urville_Station> (2005-12-05)
@@ -1836,12 +1837,8 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	HST		-10:00	-	HST
-Zone	PST8PDT		 -8:00	US	P%sT
 Zone	MST		 -7:00	-	MST
-Zone	MST7MDT		 -7:00	US	M%sT
-Zone	CST6CDT		 -6:00	US	C%sT
 Zone	EST		 -5:00	-	EST
-Zone	EST5EDT		 -5:00	US	E%sT
 Zone	WET		  0:00	EU	WE%sT
 Zone	CET		  1:00	C-Eur	CE%sT
 Zone	MET		  1:00	C-Eur	ME%sT