contrib/tzdata: import tzdata 2021b

Merge commit 'a5725262945a2971af3b808088217fe975e8364e' Changes: https://github.com/eggert/tz/blob/2021b/NEWS MFC after: 3 days
2021-09-26 14:45:39 +08:00 · 2021-09-26 14:45:39 +08:00 · 94c2d487f1
commit 94c2d487f1
parent cb17f4a6bd a572526294
20 changed files with 1094 additions and 574 deletions
--- a/contrib/tzdata/CONTRIBUTING
+++ b/contrib/tzdata/CONTRIBUTING
@ -26,8 +26,11 @@ to work well.  Additions to data should contain commentary citing
 reliable sources as justification.  Citations should use https: URLs
 if available.
 For changes that fix sensitive security-related bugs, please see the
 file SECURITY.
 Please submit changes against either the latest release in
-<https://www.iana.org/time-zones> or the master branch of the development
+<https://www.iana.org/time-zones> or the main branch of the development
 repository.  The latter is preferred.  If you use Git the following
 workflow may be helpful:
@ -36,9 +39,9 @@ workflow may be helpful:
      git clone https://github.com/eggert/tz.git
      cd tz
-  * Get current with the master branch.
+  * Get current with the main branch.
-      git checkout master
+      git checkout main
      git pull
  * Switch to a new branch for the changes.  Choose a different
@ -70,17 +73,17 @@ workflow may be helpful:
  * Create patch files 0001-*, 0002-*, ...
-      git format-patch master
+      git format-patch main
  * After reviewing the patch files, send the patches to tz@iana.org
    for others to review.
-      git send-email master
+      git send-email main
    For an archived example of such an email, see
    <https://mm.icann.org/pipermail/tz/2018-February/026122.html>.
-  * Start anew by getting current with the master branch again
+  * Start anew by getting current with the main branch again
    (the second step above).
 Please do not create issues or pull requests on GitHub, as the
--- a/contrib/tzdata/Makefile
+++ b/contrib/tzdata/Makefile
@ -45,9 +45,9 @@ LOCALTIME=	GMT
 #
 # Any other value for POSIXRULES is obsolete and should not be relied on, as:
 # * It does not work correctly in popular implementations such as GNU/Linux.
-# * It does not work in the tzdb implementation for timestamps after 2037.
+# * It does not work even in tzcode, except for historical timestamps
-# * It is incompatible with 'zic -b slim' if POSIXRULES specifies transitions
+#   that precede the last explicit transition in the POSIXRULES file.
-#   at standard time or UT rather than at local time.
+#   Hence it typically does not work for current and future timestamps.
 # In short, software should avoid ruleless settings like TZ='EET-2EEST'
 # and so should not depend on the value of POSIXRULES.
 #
@ -122,8 +122,8 @@ LIBDIR = $(TOPDIR)/$(USRDIR)/lib
 # Types to try, as an alternative to time_t.
 TIME_T_ALTERNATIVES = $(TIME_T_ALTERNATIVES_HEAD) $(TIME_T_ALTERNATIVES_TAIL)
-TIME_T_ALTERNATIVES_HEAD = int64_t
+TIME_T_ALTERNATIVES_HEAD = int_least64_t
-TIME_T_ALTERNATIVES_TAIL = int32_t uint32_t uint64_t
+TIME_T_ALTERNATIVES_TAIL = int_least32_t uint_least32_t uint_least64_t
 # What kind of TZif data files to generate.  (TZif is the binary time
 # zone data format that zic generates; see Internet RFC 8536.)
@ -152,8 +152,10 @@ REDO=		posix_right
 # The EXPIRES_LINE value matters only if REDO's value contains "right".
 # If you change EXPIRES_LINE, remove the leapseconds file before running "make".
 # zic's support for the Expires line was introduced in tzdb 2020a,
-# and EXPIRES_LINE defaults to 0 for now so that the leapseconds file
+# and was modified in tzdb 2021b to generate version 4 TZif files.
-# can be given to older zic implementations.
+# EXPIRES_LINE defaults to 0 for now so that the leapseconds file
 # can be given to pre-2020a zic implementations and so that TZif files
 # built by newer zic implementations can be read by pre-2021b libraries.
 EXPIRES_LINE=	0
 # To install data in text form that has all the information of the TZif data,
@ -210,6 +212,7 @@ LDLIBS=
 #  -DHAVE_LOCALTIME_R=0 if your system lacks a localtime_r function
 #  -DHAVE_LOCALTIME_RZ=0 if you do not want zdump to use localtime_rz
 #	localtime_rz can make zdump significantly faster, but is nonstandard.
 #  -DHAVE_MALLOC_ERRNO=0 if malloc etc. do not set errno on failure.
 #  -DHAVE_POSIX_DECLS=0 if your system's include files do not declare
 #	functions like 'link' or variables like 'tzname' required by POSIX
 #  -DHAVE_SNPRINTF=0 if your system lacks the snprintf function
@ -220,7 +223,6 @@ LDLIBS=
 #  -DHAVE_STRTOLL=0 if your system lacks the strtoll function
 #  -DHAVE_SYMLINK=0 if your system lacks the symlink function
 #  -DHAVE_SYS_STAT_H=0 if your compiler lacks a <sys/stat.h>
 #  -DHAVE_SYS_WAIT_H=0 if your compiler lacks a <sys/wait.h>
 #  -DHAVE_TZSET=0 if your system lacks a tzset function
 #  -DHAVE_UNISTD_H=0 if your compiler lacks a <unistd.h>
 #  -Dlocale_t=XXX if your system uses XXX instead of locale_t
@ -257,22 +259,26 @@ LDLIBS=
 GCC_INSTRUMENT = \
  -fsanitize=undefined -fsanitize-address-use-after-scope \
  -fsanitize-undefined-trap-on-error -fstack-protector
 # Omit -fanalyzer from GCC_DEBUG_FLAGS, as it makes GCC too slow.
 GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
  $(GCC_INSTRUMENT) \
  -Wall -Wextra \
  -Walloc-size-larger-than=100000 -Warray-bounds=2 \
  -Wbad-function-cast -Wcast-align=strict -Wdate-time \
  -Wdeclaration-after-statement -Wdouble-promotion \
  -Wduplicated-branches -Wduplicated-cond \
  -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \
-  -Winit-self -Wjump-misses-init -Wlogical-op \
+  -Winit-self -Wlogical-op \
  -Wmissing-declarations -Wmissing-prototypes -Wnested-externs \
  -Wnull-dereference \
  -Wold-style-definition -Woverlength-strings -Wpointer-arith \
-  -Wshadow -Wshift-overflow=2 -Wstrict-prototypes -Wstringop-overflow=4 \
+  -Wshadow -Wshift-overflow=2 -Wstrict-overflow \
  -Wstrict-prototypes -Wstringop-overflow=4 \
  -Wstringop-truncation -Wsuggest-attribute=cold \
  -Wsuggest-attribute=const -Wsuggest-attribute=format \
  -Wsuggest-attribute=malloc \
  -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure \
-  -Wtrampolines -Wundef -Wuninitialized -Wunused \
+  -Wtrampolines -Wundef -Wuninitialized -Wunused-macros \
  -Wvariadic-macros -Wvla -Wwrite-strings \
  -Wno-address -Wno-format-nonliteral -Wno-sign-compare \
  -Wno-type-limits -Wno-unused-parameter
@ -523,7 +529,7 @@ TZS_YEAR=	2050
 TZS_CUTOFF_FLAG=	-c $(TZS_YEAR)
 TZS=		to$(TZS_YEAR).tzs
 TZS_NEW=	to$(TZS_YEAR)new.tzs
-TZS_DEPS=	$(PRIMARY_YDATA) asctime.c localtime.c \
+TZS_DEPS=	$(YDATA) asctime.c localtime.c \
 			private.h tzfile.h zdump.c zic.c
 # EIGHT_YARDS is just a yard short of the whole ENCHILADA.
 EIGHT_YARDS = $(COMMON) $(DOCS) $(SOURCES) $(DATA) $(MISC) tzdata.zi
@ -796,9 +802,10 @@ check_links:	checklinks.awk $(TDATA_TO_CHECK) tzdata.zi
 		$(AWK) -f checklinks.awk tzdata.zi
 		touch $@
-check_tables:	checktab.awk $(PRIMARY_YDATA) $(ZONETABLES)
+check_tables:	checktab.awk $(YDATA) backward $(ZONETABLES)
 		for tab in $(ZONETABLES); do \
-		  $(AWK) -f checktab.awk -v zone_table=$$tab $(PRIMARY_YDATA) \
+		  test "$$tab" = zone.tab && links='$(BACKWARD)' || links=''; \
 		  $(AWK) -f checktab.awk -v zone_table=$$tab $(YDATA) $$links \
 		    || exit; \
 		done
 		touch $@
@ -952,6 +959,12 @@ check_public: $(VERSION_DEPS)
 		  public.dir/zic -v -d public.dir/zoneinfo $$i 2>&1 || exit; \
 		done
 		public.dir/zic -v -d public.dir/zoneinfo-all $(TDATA_TO_CHECK)
 		:
 		: Also check 'backzone' syntax.
 		rm public.dir/main.zi
 		cd public.dir && $(MAKE) PACKRATDATA=backzone main.zi
 		public.dir/zic -d public.dir/zoneinfo main.zi
 		:
 		rm -fr public.dir
 		touch $@
@ -964,7 +977,7 @@ $(TIME_T_ALTERNATIVES): $(VERSION_DEPS)
 		mkdir $@.dir
 		ln $(VERSION_DEPS) $@.dir
 		case $@ in \
-		  int32_t) range=-2147483648,2147483648;; \
+		  int*32_t) range=-2147483648,2147483648;; \
 		  u*) range=0,4294967296;; \
 		  *) range=-4294967296,4294967296;; \
 		esac && \
--- a/contrib/tzdata/NEWS
+++ b/contrib/tzdata/NEWS
@ -1,5 +1,228 @@
 News for the tz database
 Release 2021b - 2021-09-24 16:23:00 -0700
  Briefly:
    Jordan now starts DST on February's last Thursday.
    Samoa no longer observes DST.
    Merge more location-based Zones whose timestamps agree since 1970.
    Move some backward-compatibility links to 'backward'.
    Rename Pacific/Enderbury to Pacific/Kanton.
    Correct many pre-1993 transitions in Malawi, Portugal, etc.
    zic now creates each output file or link atomically.
    zic -L no longer omits the POSIX TZ string in its output.
    zic fixes for truncation and leap second table expiration.
    zic now follows POSIX for TZ strings using all-year DST.
    Fix some localtime crashes and bugs in obscure cases.
    zdump -v now outputs more-useful boundary cases.
    tzfile.5 better matches a draft successor to RFC 8536.
    A new file SECURITY.
  This release is prompted by recent announcements by Jordan and Samoa.
  It incorporates many other changes that had accumulated since 2021a.
  However, it omits most proposed changes that merged all Zones
  agreeing since 1970, as concerns were raised about doing too many of
  these changes at once.  It does keeps some of these changes in the
  interest of making tzdb more equitable one step at a time; see
  "Merge more location-based Zones" below.
  Changes to future timestamps
    Jordan now starts DST on February's last Thursday.
    (Thanks to Steffen Thorsen.)
    Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
  Changes to zone name
    Rename Pacific/Enderbury to Pacific/Kanton.  When we added
    Enderbury in 1993, we did not know that it is uninhabited and that
    Kanton (population two dozen) is the only inhabited location in
    that timezone.  The old name is now a backward-compatility link.
  Changes to past timestamps
    Correct many pre-1993 transitions, fixing entries originally
    derived from Shanks, Whitman, and Mundell.  The fixes include:
      - Barbados: standard time was introduced in 1911, not 1932; and
 	DST was observed in 1942-1944
      - Cook Islands: In 1899 they switched from east to west of GMT,
 	celebrating Christmas for two days.  They (and Niue) switched
 	to standard time in 1952, not 1901.
      - Guyana: corrected LMT for Georgetown; the introduction of
 	standard time in 1911, not 1915; and corrections to 1975 and
 	1992 transitions
      - Kanton: uninhabited before 1937-08-31
      - Niue: only observed -11:20 from 1952 through 1964, then went to
        -11 instead of -11:30
      - Portugal: DST was observed in 1950
      - Tonga: corrected LMT; the introduction of standard time in 1945,
        not 1901; and corrections to the transition from +12:20 to +13
        in 1961, not 1941
    Additional fixes to entries in the 'backzone' file include:
      - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
      - The Gambia: 1933 and 1942 transitions
      - Malawi: several 1911 through 1925 transitions
      - Sierra Leone: several 1913 through 1941 transitions, and DST
 	was NOT observed in 1957 through 1962
    (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
    Alois Treindl.)
    Merge more location-based Zones whose timestamps agree since 1970,
    as pre-1970 timestamps are out of scope.  This is part of a
    process that has been ongoing since 2013.  This does not affect
    post-1970 timestamps, and timezone historians who build with 'make
    PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
    When merging, keep the most-populous location's data, and move
    data for other locations to 'backzone' with a backward
    link in 'backward'.  For example, move America/Creston data to
    'backzone' with a link in 'backward' from America/Phoenix because
    the two timezones' timestamps agree since 1970; this change
    affects some pre-1968 timestamps in America/Creston because
    Creston and Phoenix disagreed before 1968.  The affected Zones
    are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
    America/Creston, America/Curacao, America/Nassau,
    America/Port_of_Spain, Antarctica/DumontDUrville, and
    Antarctica/Syowa.
  Changes to maintenance procedure
    The new file SECURITY covers how to report security-related bugs.
    Several backward-compatibility links have been moved to the
    'backward' file.  These links, which range from Africa/Addis_Ababa
    to Pacific/Saipan, are only for compatibility with now-obsolete
    guidelines suggesting an entry for every ISO 3166 code.
    The intercontinental convenience links Asia/Istanbul and
    Europe/Nicosia have also been moved to 'backward'.
  Changes to code
    zic now creates each output file or link atomically,
    possibly by creating a temporary file and then renaming it.
    This avoids races where a TZ setting would temporarily stop
    working while zic was installing a replacement file or link.
    zic -L no longer omits the POSIX TZ string in its output.
    Starting with 2020a, zic -L truncated its output according to the
    "Expires" directive or "#expires" comment in the leapseconds file.
    The resulting TZif files omitted daylight saving transitions after
    the leap second table expired, which led to far less-accurate
    predictions of times after the expiry.  Although future timestamps
    cannot be converted accurately in the presence of leap seconds, it
    is more accurate to convert near-future timestamps with a few
    seconds error than with an hour error, so zic -L no longer
    truncates output in this way.
    Instead, when zic -L is given the "Expires" directive, it now
    outputs the expiration by appending a no-change entry to the leap
    second table.  Although this should work well with most TZif
    readers, it does not conform to Internet RFC 8536 and some pickier
    clients (including tzdb 2017c through 2021a) reject it, so
    "Expires" directives are currently disabled by default.  To enable
    them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
    this new feature it is marked with a new TZif version number 4,
    a format intended to be documented in a successor to RFC 8536.
    zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
    that omits leap second information for the range LO..B when LO
    falls between two leap seconds A and B.  Instead, it generates a
    TZif version 4 file that represents the previously-missing
    information.
    The TZif reader now allows the leap second table to begin with a
    correction other than -1 or +1, and to contain adjacent
    transitions with equal corrections.  This supports TZif version 4.
    The TZif reader now lets leap seconds occur less than 28 days
    apart.  This supports possible future TZif extensions.
    Fix bug that caused 'localtime' etc. to crash when TZ was
    set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
    not conform to POSIX but does conform to Internet RFC 8536.
    Fix another bug that caused 'localtime' etc. to crash when TZ was
    set to a POSIX-conforming but unusual TZ string like
    "EST5EDT4,0/0,J365/0", where almost all the year is DST.
    Fix yet another bug that caused 'localtime' etc. to mishandle slim
    TZif files containing leap seconds after the last explicit
    transition in the table, or when handling far-future timestamps
    in slim TZif files lacking leap seconds.
    Fix localtime misbehavior involving positive leap seconds.
    This change affects only behavior for "right" system time,
    which contains leap seconds, and only if the UT offset is
    not a multiple of 60 seconds when a positive leap second occurs.
    (No such timezone exists in tzdb, luckily.)  Without the fix,
    the timestamp was ambiguous during a positive leap second.
    With the fix, any seconds occurring after a positive leap second
    and within the same localtime minute are counted through 60, not
    through 59; their UT offset (tm_gmtoff) is the same as before.
    Here is how the fix affects timestamps in a timezone with UT
    offset +01:23:45 (5025 seconds) and with a positive leap second at
    1972-06-30 23:59:60 UTC (78796800):
 	time_t    without the fix      with the fix
 	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
 	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
 	...
 	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
 	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
    Fix an unlikely bug that caused 'localtime' etc. to misbehave if
    civil time changes a few seconds before time_t wraps around, when
    leap seconds are enabled.
    Fix bug in zic -r; in some cases, the dummy time type after the
    last time transition disagreed with the TZ string, contrary to
    Internet RFC 8563 section 3.3.
    Fix a bug with 'zic -r @X' when X is a negative leap second that
    has a nonnegative correction.  Without the fix, the output file
    was truncated so that X appeared to be a positive leap second.
    Fix a similar, even-less-likely bug when truncating at a positive
    leap second that has a nonpositive correction.
    zic -r now reports an error if given rolling leap seconds, as this
    usage has never generally worked and is evidently unused.
    zic now generates a POSIX-conforming TZ string for TZif files
    where all-year DST is predicted for the indefinite future.
    For example, for all-year Eastern Daylight Time, zic now generates
    "XXX3EDT4,0/0,J365/23" where it previously generated
    "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
    noting the possibility of POSIX conformance.)
    zic.c no longer requires sys/wait.h (thanks to spazmodius for
    noting it wasn't needed).
    When reading slim TZif files, zdump no longer mishandles leap
    seconds on the rare platforms where time_t counts leap seconds,
    fixing a bug introduced in 2014g.
    zdump -v now outputs timestamps at boundaries of what localtime
    and gmtime can represent, instead of the less-useful timestamps
    one day after the minimum and one day before the maximum.
    (Thanks to Arthur David Olson for prototype code, and to Manuela
    Friedrich for debugging help.)
    zdump's -c and -t options are now consistently inclusive for the
    lower time bound and exclusive for the upper.  Formerly they were
    inconsistent.  (Confusion noted by Martin Burnicki.)
  Changes to build procedure
    You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
    non-POSIX hosts where malloc doesn't set errno.
    (Problem reported by Jan Engelhardt.)
  Changes to documentation
    tzfile.5 better matches a draft successor to RFC 8536
    <https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.
 Release 2021a - 2021-01-24 10:54:57 -0800
  Changes to future timestamps
@ -31,7 +254,7 @@ Release 2020e - 2020-12-22 15:14:34 -0800
    Correct many pre-1986 transitions, fixing entries originally
    derived from Shanks.  The fixes include:
      - Australia: several 1917 through 1971 transitions
-      - Bahamas: several 1941 through 1945 transitions
+      - The Bahamas: several 1941 through 1945 transitions
      - Bermuda: several 1917 through 1956 transitions
      - Belize: several 1942 through 1968 transitions
      - Ghana: several 1915 through 1956 transitions
@ -825,8 +1048,8 @@ Release 2018d - 2018-03-22 07:05:46 -0700
    Institute in Montevideo.
    (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
-    Enderbury and Kiritimati skipped New Year's Eve 1994, not
+    East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
-    New Year's Day 1995.  (Thanks to Kerry Shetline.)
+    (Thanks to Kerry Shetline.)
    Fix the 1912-01-01 transition for Portugal and its colonies.
    This transition was at 00:00 according to the new UT offset, not
--- a/contrib/tzdata/africa
+++ b/contrib/tzdata/africa
@ -30,9 +30,6 @@
 # Milne J. Civil time. Geogr J. 1899 Feb;13(2):173-94.
 # https://www.jstor.org/stable/1774359
 #
 # A reliable and entertaining source about time zones is
 # Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
 #
 # European-style abbreviations are commonly used along the Mediterranean.
 # For sub-Saharan Africa abbreviations were less standardized.
 # Previous editions of this database used WAT, CAT, SAT, and EAT
@ -153,15 +150,6 @@ Zone	Africa/Ndjamena	1:00:12 -	LMT	1912        # N'Djamena
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Abidjan	-0:16:08 -	LMT	1912
 			 0:00	-	GMT
 Link Africa/Abidjan Africa/Bamako	# Mali
 Link Africa/Abidjan Africa/Banjul	# Gambia
 Link Africa/Abidjan Africa/Conakry	# Guinea
 Link Africa/Abidjan Africa/Dakar	# Senegal
 Link Africa/Abidjan Africa/Freetown	# Sierra Leone
 Link Africa/Abidjan Africa/Lome		# Togo
 Link Africa/Abidjan Africa/Nouakchott	# Mauritania
 Link Africa/Abidjan Africa/Ouagadougou	# Burkina Faso
 Link Africa/Abidjan Atlantic/St_Helena	# St Helena
 # Djibouti
 # See Africa/Nairobi.
@ -381,93 +369,8 @@ Zone	Africa/Cairo	2:05:09 -	LMT	1900 Oct
 # Gabon
 # See Africa/Lagos.
-# Gambia
+# The Gambia
 # See Africa/Abidjan.
 # Ghana
 # From P Chan (2020-11-20):
 # Interpretation Amendment Ordinance, 1915 (No.24 of 1915) [1915-11-02]
 # Ordinances of the Gold Coast, Ashanti, Northern Territories 1915, p 69-71
 # https://books.google.com/books?id=ErA-AQAAIAAJ&pg=PA70
 # This Ordinance added "'Time' shall mean Greenwich Mean Time" to the
 # Interpretation Ordinance, 1876.
 #
 # Determination of the Time Ordinance, 1919 (No. 18 of 1919) [1919-11-24]
 # Ordinances of the Gold Coast, Ashanti, Northern Territories 1919, p 75-76
 # https://books.google.com/books?id=MbA-AQAAIAAJ&pg=PA75
 # This Ordinance removed the previous definition of time and introduced DST.
 #
 # Time Determination Ordinance (Cap. 214)
 # The Laws of the Gold Coast (including Togoland Under British Mandate)
 # Vol. II (1937), p 2328
 # https://books.google.com/books?id=Z7M-AQAAIAAJ&pg=PA2328
 # Revised edition of the 1919 Ordinance.
 #
 # Time Determination (Amendment) Ordinance, 1940 (No. 9 of 1940) [1940-04-06]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1940, p 22
 # https://books.google.com/books?id=1ao-AQAAIAAJ&pg=PA22
 # This Ordinance changed the forward transition from September to May.
 #
 # Defence (Time Determination Ordinance Amendment) Regulations, 1942
 # (Regulations No. 6 of 1942) [1942-01-31, commenced on 1942-02-08]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1942, p 48
 # https://books.google.com/books?id=Das-AQAAIAAJ&pg=PA48
 # These regulations advanced the [standard] time by thirty minutes.
 #
 # Defence (Time Determination Ordinance Amendment (No.2)) Regulations,
 # 1942 (Regulations No. 28 of 1942) [1942-04-25]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1942, p 87
 # https://books.google.com/books?id=Das-AQAAIAAJ&pg=PA87
 # These regulations abolished DST and changed the time to GMT+0:30.
 #
 # Defence (Revocation) (No.4) Regulations, 1945 (Regulations No. 45 of
 # 1945) [1945-10-24, commenced on 1946-01-06]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1945, p 256
 # https://books.google.com/books?id=9as-AQAAIAAJ&pg=PA256
 # These regulations revoked the previous two sets of Regulations.
 #
 # Time Determination (Amendment) Ordinance, 1945 (No. 18 of 1945) [1946-01-06]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1945, p 69
 # https://books.google.com/books?id=9as-AQAAIAAJ&pg=PA69
 # This Ordinance abolished DST.
 #
 # Time Determination (Amendment) Ordinance, 1950 (No. 26 of 1950) [1950-07-22]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1950, p 35
 # https://books.google.com/books?id=e60-AQAAIAAJ&pg=PA35
 # This Ordinance restored DST but with thirty minutes offset.
 #
 # Time Determination Ordinance (Cap. 264)
 # The Laws of the Gold Coast, Vol. V (1954), p 380
 # https://books.google.com/books?id=Mqc-AQAAIAAJ&pg=PA380
 # Revised edition of the Time Determination Ordinance.
 #
 # Time Determination (Amendment) Ordinance, 1956 (No. 21 of 1956) [1956-08-29]
 # Annual Volume of the Ordinances of the Gold Coast Enacted During the
 # Year 1956, p 83
 # https://books.google.com/books?id=VLE-AQAAIAAJ&pg=PA83
 # This Ordinance abolished DST.
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Ghana	1919	only	-	Nov	24	0:00	0:20	+0020
 Rule	Ghana	1920	1942	-	Jan	 1	2:00	0	GMT
 Rule	Ghana	1920	1939	-	Sep	 1	2:00	0:20	+0020
 Rule	Ghana	1940	1941	-	May	 1	2:00	0:20	+0020
 Rule	Ghana	1950	1955	-	Sep	 1	2:00	0:30	+0030
 Rule	Ghana	1951	1956	-	Jan	 1	2:00	0	GMT
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Accra	-0:00:52 -	LMT	1915 Nov  2
 			 0:00	Ghana	%s	1942 Feb  8
 			 0:30	-	+0030	1946 Jan  6
 			 0:00	Ghana	%s
 # Guinea
 # See Africa/Abidjan.
@ -533,15 +436,6 @@ Zone	Africa/Nairobi	2:27:16	-	LMT	1908 May
 			2:30	-	+0230	1936 Dec 31 24:00
 			2:45	-	+0245	1942 Jul 31 24:00
 			3:00	-	EAT
 Link Africa/Nairobi Africa/Addis_Ababa	 # Ethiopia
 Link Africa/Nairobi Africa/Asmara	 # Eritrea
 Link Africa/Nairobi Africa/Dar_es_Salaam # Tanzania
 Link Africa/Nairobi Africa/Djibouti
 Link Africa/Nairobi Africa/Kampala	 # Uganda
 Link Africa/Nairobi Africa/Mogadishu	 # Somalia
 Link Africa/Nairobi Indian/Antananarivo	 # Madagascar
 Link Africa/Nairobi Indian/Comoro
 Link Africa/Nairobi Indian/Mayotte
 # Lesotho
 # See Africa/Johannesburg.
@ -732,7 +626,7 @@ Zone Indian/Mauritius	3:50:00 -	LMT	1907 # Port Louis
 # See Africa/Nairobi.
 # Morocco
-# See the 'europe' file for Spanish Morocco (Africa/Ceuta).
+# See Africa/Ceuta for Spanish Morocco.
 # From Alex Krivenyshev (2008-05-09):
 # Here is an article that Morocco plan to introduce Daylight Saving Time between
@ -1228,13 +1122,6 @@ Zone Africa/El_Aaiun	-0:52:48 -	LMT	1934 Jan # El Aaiún
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Maputo	2:10:20 -	LMT	1903 Mar
 			2:00	-	CAT
 Link Africa/Maputo Africa/Blantyre	# Malawi
 Link Africa/Maputo Africa/Bujumbura	# Burundi
 Link Africa/Maputo Africa/Gaborone	# Botswana
 Link Africa/Maputo Africa/Harare	# Zimbabwe
 Link Africa/Maputo Africa/Kigali	# Rwanda
 Link Africa/Maputo Africa/Lubumbashi	# E Dem. Rep. of Congo
 Link Africa/Maputo Africa/Lusaka	# Zambia
 # Namibia
@ -1382,23 +1269,12 @@ Zone	Africa/Lagos	0:13:35 -	LMT	1905 Jul  1
 			0:13:35	-	LMT	1914 Jan  1
 			0:30	-	+0030	1919 Sep  1
 			1:00	-	WAT
 Link Africa/Lagos Africa/Bangui	     # Central African Republic
 Link Africa/Lagos Africa/Brazzaville # Rep. of the Congo
 Link Africa/Lagos Africa/Douala	     # Cameroon
 Link Africa/Lagos Africa/Kinshasa    # Dem. Rep. of the Congo (west)
 Link Africa/Lagos Africa/Libreville  # Gabon
 Link Africa/Lagos Africa/Luanda	     # Angola
 Link Africa/Lagos Africa/Malabo	     # Equatorial Guinea
 Link Africa/Lagos Africa/Niamey	     # Niger
 Link Africa/Lagos Africa/Porto-Novo  # Benin
 # Réunion
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Reunion	3:41:52 -	LMT	1911 Jun # Saint-Denis
 			4:00	-	+04
 #
 # Crozet Islands also observes Réunion time; see the 'antarctica' file.
 #
 # Scattered Islands (Îles Éparses) administered from Réunion are as follows.
 # The following information about them is taken from
 # Îles Éparses (<http://www.outre-mer.gouv.fr/domtom/ile.htm>, 1997-07-22,
@ -1490,8 +1366,6 @@ Rule	SA	1943	1944	-	Mar	Sun>=15	2:00	0	-
 Zone Africa/Johannesburg 1:52:00 -	LMT	1892 Feb 8
 			1:30	-	SAST	1903 Mar
 			2:00	SA	SAST
 Link Africa/Johannesburg Africa/Maseru	   # Lesotho
 Link Africa/Johannesburg Africa/Mbabane    # Eswatini
 #
 # Marion and Prince Edward Is
 # scientific station since 1947
@ -1527,12 +1401,13 @@ Zone	Africa/Khartoum	2:10:08 -	LMT	1931
 			3:00	-	EAT	2017 Nov  1
 			2:00	-	CAT
 # South Sudan
 # From Steffen Thorsen (2021-01-18):
 # "South Sudan will change its time zone by setting the clock back 1
 # hour on February 1, 2021...."
 # from https://eyeradio.org/south-sudan-adopts-new-time-zone-makuei/
 # South Sudan
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Juba	2:06:28 -	LMT	1931
 			2:00	Sudan	CA%sT	2000 Jan 15 12:00
@ -1637,7 +1512,7 @@ Rule	Tunisia	2005	only	-	Sep	30	 1:00s	0	-
 Rule	Tunisia	2006	2008	-	Mar	lastSun	 2:00s	1:00	S
 Rule	Tunisia	2006	2008	-	Oct	lastSun	 2:00s	0	-
-# See Europe/Paris for PMT-related transitions.
+# See Europe/Paris commentary for PMT-related transitions.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Tunis	0:40:44 -	LMT	1881 May 12
 			0:09:21	-	PMT	1911 Mar 11 # Paris Mean Time
--- a/contrib/tzdata/antarctica
+++ b/contrib/tzdata/antarctica
@ -148,7 +148,7 @@ Zone Antarctica/Mawson	0	-	-00	1954 Feb 13
 #
 # Alfred Faure, Possession Island, Crozet Islands, -462551+0515152, since 1964;
 #	sealing & whaling stations operated variously 1802/1911+;
-#	see Indian/Reunion.
+#	see Asia/Dubai.
 #
 # Martin-de-Viviès, Amsterdam Island, -374105+0773155, since 1950
 # Port-aux-Français, Kerguelen Islands, -492110+0701303, since 1951;
@ -162,17 +162,7 @@ Zone Indian/Kerguelen	0	-	-00	1950 # Port-aux-Français
 			5:00	-	+05
 #
 # year-round base in the main continent
-# Dumont d'Urville, Île des Pétrels, -6640+14001, since 1956-11
+# Dumont d'Urville - see Pacific/Port_Moresby.
 # <https://en.wikipedia.org/wiki/Dumont_d'Urville_Station> (2005-12-05)
 #
 # Another base at Port-Martin, 50km east, began operation in 1947.
 # It was destroyed by fire on 1952-01-14.
 #
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/DumontDUrville 0 -	-00	1947
 			10:00	-	+10	1952 Jan 14
 			0	-	-00	1956 Nov
 			10:00	-	+10
 # France & Italy - year-round base
 # Concordia, -750600+1232000, since 2005
@ -188,20 +178,7 @@ Zone Antarctica/DumontDUrville 0 -	-00	1947
 # Zuchelli, Terra Nova Bay, -744140+1640647, since 1986
 # Japan - year-round bases
-# Syowa (also known as Showa), -690022+0393524, since 1957
+# See Asia/Riyadh.
 #
 # From Hideyuki Suzuki (1999-02-06):
 # In all Japanese stations, +0300 is used as the standard time.
 #
 # Syowa station, which is the first antarctic station of Japan,
 # was established on 1957-01-29.  Since Syowa station is still the main
 # station of Japan, it's appropriate for the principal location.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/Syowa	0	-	-00	1957 Jan 29
 			3:00	-	+03
 # See:
 # NIPR Antarctic Research Activities (1999-08-17)
 # http://www.nipr.ac.jp/english/ara01.html
 # S Korea - year-round base
 # Jang Bogo, Terra Nova Bay, -743700+1641205 since 2014
--- a/contrib/tzdata/asia
+++ b/contrib/tzdata/asia
@ -34,9 +34,6 @@
 # Byalokoz EL. New Counting of Time in Russia since July 1, 1919.
 # (See the 'europe' file for a fuller citation.)
 #
 # A reliable and entertaining source about time zones is
 # Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
 #
 # The following alphabetic abbreviations appear in these tables
 # (corrections are welcome):
 #	     std  dst
@ -1176,10 +1173,9 @@ Zone	Asia/Famagusta	2:15:48	-	LMT	1921 Nov 14
 			2:00	EUAsia	EE%sT	2016 Sep  8
 			3:00	-	+03	2017 Oct 29 1:00u
 			2:00	EUAsia	EE%sT
 # Classically, Cyprus belongs to Asia; e.g. see Herodotus, Histories, I.72.
 # However, for various reasons many users expect to find it under Europe.
-Link	Asia/Nicosia	Europe/Nicosia
+# See the 'backward' file for the Europe/Nicosia link.
 # Georgia
 # From Paul Eggert (1994-11-19):
@ -2234,6 +2230,14 @@ Zone	Asia/Tokyo	9:18:59	-	LMT	1887 Dec 31 15:00u
 # From Paul Eggert (2013-12-11):
 # As Steffen suggested, consider the past 21-month experiment to be DST.
 # From Steffen Thorsen (2021-09-24):
 # The Jordanian Government announced yesterday that they will start DST
 # in February instead of March:
 # https://petra.gov.jo/Include/InnerPage.jsp?ID=37683&lang=en&name=en_news (English)
 # https://petra.gov.jo/Include/InnerPage.jsp?ID=189969&lang=ar&name=news (Arabic)
 # From the Arabic version, it seems to say it would be at midnight
 # (assume 24:00) on the last Thursday in February, starting from 2022.
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Jordan	1973	only	-	Jun	6	0:00	1:00	S
 Rule	Jordan	1973	1975	-	Oct	1	0:00	0	-
@ -2264,8 +2268,9 @@ Rule	Jordan	2004	only	-	Oct	15	0:00s	0	-
 Rule	Jordan	2005	only	-	Sep	lastFri	0:00s	0	-
 Rule	Jordan	2006	2011	-	Oct	lastFri	0:00s	0	-
 Rule	Jordan	2013	only	-	Dec	20	0:00	0	-
-Rule	Jordan	2014	max	-	Mar	lastThu	24:00	1:00	S
+Rule	Jordan	2014	2021	-	Mar	lastThu	24:00	1:00	S
 Rule	Jordan	2014	max	-	Oct	lastFri	0:00s	0	-
 Rule	Jordan	2022	max	-	Feb	lastThu	24:00	1:00	S
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Amman	2:23:44 -	LMT	1931
 			2:00	Jordan	EE%sT
@ -2740,7 +2745,8 @@ Rule	NBorneo	1935	1941	-	Dec	14	0:00	0	-
 #
 # peninsular Malaysia
 # taken from Mok Ly Yng (2003-10-30)
-# http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html
+# https://web.archive.org/web/20190822231045/http://www.math.nus.edu.sg/~mathelmr/teaching/timezone.html
 # This agrees with Singapore since 1905-06-01.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Asia/Kuala_Lumpur	6:46:46 -	LMT	1901 Jan  1
 			6:55:25	-	SMT	1905 Jun  1 # Singapore M.T.
@ -3500,6 +3506,12 @@ Zone	Asia/Hebron	2:20:23	-	LMT	1900 Oct
 # influence of the sources.  There is no current abbreviation for DST,
 # so use "PDT", the usual American style.
 # From P Chan (2021-05-10):
 # Here's a fairly comprehensive article in Japanese:
 # https://wiki.suikawiki.org/n/Philippine%20Time
 # From Paul Eggert (2021-05-10):
 # The info in the Japanese table has not been absorbed (yet) below.
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Phil	1936	only	-	Nov	1	0:00	1:00	D
 Rule	Phil	1937	only	-	Feb	1	0:00	0	S
@ -3519,7 +3531,6 @@ Zone	Asia/Manila	-15:56:00 -	LMT	1844 Dec 31
 Zone	Asia/Qatar	3:26:08 -	LMT	1920     # Al Dawhah / Doha
 			4:00	-	+04	1972 Jun
 			3:00	-	+03
 Link Asia/Qatar Asia/Bahrain
 # Saudi Arabia
 #
@ -3566,12 +3577,10 @@ Link Asia/Qatar Asia/Bahrain
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Riyadh	3:06:52 -	LMT	1947 Mar 14
 			3:00	-	+03
 Link Asia/Riyadh Asia/Aden	# Yemen
 Link Asia/Riyadh Asia/Kuwait
 # Singapore
 # taken from Mok Ly Yng (2003-10-30)
-# http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html
+# https://web.archive.org/web/20190822231045/http://www.math.nus.edu.sg/~mathelmr/teaching/timezone.html
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Singapore	6:55:25 -	LMT	1901 Jan  1
 			6:55:25	-	SMT	1905 Jun  1 # Singapore M.T.
@ -3824,8 +3833,6 @@ Zone	Asia/Dushanbe	4:35:12 -	LMT	1924 May  2
 Zone	Asia/Bangkok	6:42:04	-	LMT	1880
 			6:42:04	-	BMT	1920 Apr # Bangkok Mean Time
 			7:00	-	+07
 Link Asia/Bangkok Asia/Phnom_Penh	# Cambodia
 Link Asia/Bangkok Asia/Vientiane	# Laos
 # Turkmenistan
 # From Shanks & Pottenger.
@ -3840,7 +3847,6 @@ Zone	Asia/Ashgabat	3:53:32 -	LMT	1924 May  2 # or Ashkhabad
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Dubai	3:41:12 -	LMT	1920
 			4:00	-	+04
 Link Asia/Dubai Asia/Muscat	# Oman
 # Uzbekistan
 # Byalokoz 1919 says Uzbekistan was 4:27:53.
--- a/contrib/tzdata/australasia
+++ b/contrib/tzdata/australasia
@ -458,13 +458,12 @@ Zone	Pacific/Guam	-14:21:00 -	LMT	1844 Dec 31
 			 9:00	-	+09	1944 Jul 31
 			10:00	Guam	G%sT	2000 Dec 23
 			10:00	-	ChST	# Chamorro Standard Time
 Link Pacific/Guam Pacific/Saipan # N Mariana Is
 # Kiribati
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Tarawa	 11:32:04 -	LMT	1901 # Bairiki
 			 12:00	-	+12
-Zone Pacific/Enderbury	-11:24:20 -	LMT	1901
+Zone Pacific/Kanton	  0	-	-00	1937 Aug 31
 			-12:00	-	-12	1979 Oct
 			-11:00	-	-11	1994 Dec 31
 			 13:00	-	+13
@ -584,8 +583,6 @@ Zone Pacific/Chatham	12:13:48 -	LMT	1868 Nov  2
 			12:15	-	+1215	1946 Jan  1
 			12:45	Chatham	+1245/+1345
 Link Pacific/Auckland Antarctica/McMurdo
 # Auckland Is
 # uninhabited; Māori and Moriori, colonial settlers, pastoralists, sealers,
 # and scientific personnel have wintered
@ -597,13 +594,46 @@ Link Pacific/Auckland Antarctica/McMurdo
 # was probably like Pacific/Auckland
 # Cook Is
-# From Shanks & Pottenger:
+#
 # From Alexander Krivenyshev (2021-03-24):
 # In 1899 the Cook Islands celebrated Christmas twice to correct the calendar.
 # According to the old books, missionaries were unaware of
 # the International Date line, when they came from Sydney.
 # Thus the Cook Islands were one day ahead....
 # http://nzetc.victoria.ac.nz/tm/scholarly/tei-KloDisc-t1-body-d18.html
 # ... Appendix to the Journals of the House of Representatives, 1900
 # https://atojs.natlib.govt.nz/cgi-bin/atojs?a=d&d=AJHR1900-I.2.1.2.3
 # (page 20)
 #
 # From Michael Deckers (2021-03-24):
 # ... in the Cook Island Act of 1915-10-11, online at
 # http://www.paclii.org/ck/legis/ck-nz_act/cia1915132/
 # "651. The hour of the day shall in each of the islands included in the
 #  Cook Islands be determined in accordance with the meridian of that island."
 # so that local (mean?) time was still used in Rarotonga (and Niue) in 1915.
 # This was changed in the Cook Island Amendment Act of 1952-10-16 ...
 # http://www.paclii.org/ck/legis/ck-nz_act/ciaa1952212/
 # "651 (1) The hour of the day in each of the islands included in the Cook
 #  Islands, other than Niue, shall be determined as if each island were
 #  situated on the meridian one hundred and fifty-seven degrees thirty minutes
 #  West of Greenwich.  (2) The hour of the day in the Island of Niue shall be
 #  determined as if that island were situated on the meridian one hundred and
 #  seventy degrees West of Greenwich."
 # This act does not state when it takes effect, so one has to assume it
 # applies since 1952-10-16.  But there is the possibility that the act just
 # legalized prior existing practice, as we had seen with the Guernsey law of
 # 1913-06-18 for the switch in 1909-04-19.
 #
 # From Paul Eggert (2021-03-24):
 # Transitions after 1952 are from Shanks & Pottenger.
 #
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Cook	1978	only	-	Nov	12	0:00	0:30	-
 Rule	Cook	1979	1991	-	Mar	Sun>=1	0:00	0	-
 Rule	Cook	1979	1990	-	Oct	lastSun	0:00	0:30	-
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone Pacific/Rarotonga	-10:39:04 -	LMT	1901        # Avarua
+Zone Pacific/Rarotonga	13:20:56 -	LMT	1899 Dec 26 # Avarua
 			-10:39:04 -	LMT	1952 Oct 16
 			-10:30	-	-1030	1978 Nov 12
 			-10:00	Cook	-10/-0930
@ -611,10 +641,18 @@ Zone Pacific/Rarotonga	-10:39:04 -	LMT	1901        # Avarua
 # Niue
 # See Pacific/Raratonga comments for 1952 transition.
 #
 # From Tim Parenti (2021-09-13):
 # Consecutive contemporaneous editions of The Air Almanac listed -11:20 for
 # Niue as of Apr 1964 but -11 as of Aug 1964:
 #   Apr 1964: https://books.google.com/books?id=_1So677Y5vUC&pg=SL1-PA23
 #   Aug 1964: https://books.google.com/books?id=MbJloqd-zyUC&pg=SL1-PA23
 # Without greater specificity, guess 1964-07-01 for this transition.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Pacific/Niue	-11:19:40 -	LMT	1901        # Alofi
+Zone	Pacific/Niue	-11:19:40 -	LMT	1952 Oct 16	# Alofi
-			-11:20	-	-1120	1951
+			-11:20	-	-1120	1964 Jul
 			-11:30	-	-1130	1978 Oct  1
 			-11:00	-	-11
 # Norfolk
@ -673,7 +711,6 @@ Zone Pacific/Pitcairn	-8:40:20 -	LMT	1901        # Adamstown
 Zone Pacific/Pago_Pago	 12:37:12 -	LMT	1892 Jul  5
 			-11:22:48 -	LMT	1911
 			-11:00	-	SST	            # S=Samoa
 Link Pacific/Pago_Pago Pacific/Midway # in US minor outlying islands
 # Samoa (formerly and also known as Western Samoa)
@ -742,13 +779,17 @@ Link Pacific/Pago_Pago Pacific/Midway # in US minor outlying islands
 # From Paul Eggert (2014-07-08):
 # That web page currently lists transitions for 2012/3 and 2013/4.
 # Assume the pattern instituted in 2012 will continue indefinitely.
 #
 # From Geoffrey D. Bennett (2021-09-20):
 # https://www.mcil.gov.ws/storage/2021/09/MCIL-Scan_20210920_120553.pdf
 # DST has been cancelled for this year.
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	WS	2010	only	-	Sep	lastSun	0:00	1	-
 Rule	WS	2011	only	-	Apr	Sat>=1	4:00	0	-
 Rule	WS	2011	only	-	Sep	lastSat	3:00	1	-
-Rule	WS	2012	max	-	Apr	Sun>=1	4:00	0	-
+Rule	WS	2012	2021	-	Apr	Sun>=1	4:00	0	-
-Rule	WS	2012	max	-	Sep	lastSun	3:00	1	-
+Rule	WS	2012	2020	-	Sep	lastSun	3:00	1	-
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Apia	 12:33:04 -	LMT	1892 Jul  5
 			-11:26:56 -	LMT	1911
@ -795,8 +836,8 @@ Rule	Tonga	2001	2002	-	Jan	lastSun	2:00	0	-
 Rule	Tonga	2016	only	-	Nov	Sun>=1	2:00	1:00	-
 Rule	Tonga	2017	only	-	Jan	Sun>=15	3:00	0	-
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone Pacific/Tongatapu	12:19:20 -	LMT	1901
+Zone Pacific/Tongatapu	12:19:12 -	LMT	1945 Sep 10
-			12:20	-	+1220	1941
+			12:20	-	+1220	1961
 			13:00	-	+13	1999
 			13:00	Tonga	+13/+14
@ -1738,6 +1779,23 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 # One source for this is page 202 of: Bartky IR. One Time Fits All:
 # The Campaigns for Global Uniformity (2007).
 # Kanton
 # From Paul Eggert (2021-05-27):
 # Kiribati's +13 timezone is represented by Kanton, its only populated
 # island.  (It was formerly spelled "Canton", but Gilbertese lacks "C".)
 # Kanton was settled on 1937-08-31 by two British radio operators
 # <https://history.state.gov/historicaldocuments/frus1937v02/d94>;
 # Americans came the next year and built an airfield, partly to
 # establish airline service and perhaps partly anticipating the
 # next war.  Aside from the war, the airfield was used by commercial
 # airlines until long-range jets became standard; although currently
 # for emergency use only, China says it is considering rebuilding the
 # airfield for high-end niche tourism.  Kanton has about two dozen
 # people, caretakers who rotate in from the rest of Kiribati in 2-5
 # year shifts, and who use some of the leftover structures
 # <http://pipa.neaq.org/2012/06/images-of-kanton-island.html>.
 # Kwajalein
 # From an AP article (1993-08-22):
@ -2021,6 +2079,17 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 # Tonga
 # From Paul Eggert (2021-03-04):
 # In 1943 "The standard time kept is 12 hrs. 19 min. 12 sec. fast
 # on Greenwich mean time." according to the Admiralty's Hydrographic
 # Dept., Pacific Islands Pilot, Vol. II, 7th ed., 1943, p 360.
 # From Michael Deckers (2021-03-03):
 # [Ian R Bartky: "One Time Fits All: The Campaigns for Global Uniformity".
 # Stanford University Press. 2007. p. 255]:
 # On 10 September 1945 Tonga adopted a standard time 12 hours,
 # 20 minutes in advance of Greenwich.
 # From Paul Eggert (1996-01-22):
 # Today's _Wall Street Journal_ (p 1) reports that "Tonga has been plotting
 # to sneak ahead of [New Zealanders] by introducing daylight-saving time."
@ -2049,9 +2118,26 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 # The Crown Prince, presented an unanswerable argument: "Remember that
 # on the World Day of Prayer, you would be the first people on Earth
 # to say your prayers in the morning."
-
+#
-# From Paul Eggert (2006-03-22):
+# From Tim Parenti (2021-09-13), per Paul Eggert (2006-03-22) and Michael
-# Shanks & Pottenger say the transition was on 1968-10-01; go with Mundell.
+# Deckers (2021-03-03):
 # Mundell places the transition from +12:20 to +13 in 1941, while Shanks &
 # Pottenger say the transition was on 1968-10-01.
 #
 # The Air Almanac published contemporaneous tables of standard times,
 # which listed +12:20 as of Nov 1960 and +13 as of Mar 1961:
 #   Nov 1960: https://books.google.com/books?id=bVgtWM6kPZUC&pg=SL1-PA19
 #   Mar 1961: https://books.google.com/books?id=W2nItAul4g0C&pg=SL1-PA19
 # (Thanks to P Chan for pointing us toward these sources.)
 # This agrees with Bartky, who writes that "since 1961 [Tonga's] official time
 # has been thirteen hours in advance of Greenwich time" (p. 202) and further
 # writes in an endnote that this was because "the legislation was amended" on
 # 1960-10-19. (p. 255)
 #
 # Without greater specificity, presume that Bartky and the Air Almanac point to
 # a 1961-01-01 transition, as Tāufaʻāhau Tupou IV was still Crown Prince in
 # 1961 and this still jives with the gist of Mundell's telling, and go with
 # this over Shanks & Pottenger.
 # From Eric Ulevik (1999-05-03):
 # Tonga's director of tourism, who is also secretary of the National Millennium
--- a/contrib/tzdata/backward
+++ b/contrib/tzdata/backward
@ -3,50 +3,121 @@
 # This file is in the public domain, so clarified as of
 # 2009-05-17 by Arthur David Olson.
-# This file provides links between current names for timezones
+# This file provides links from old or merged timezone names to current ones.
-# and their old names.  Many names changed in late 1993.
+# Many names changed in late 1993, and many merged names moved here
 # in the period from 2013 through 2021.  Several of these names are
 # also present in the file 'backzone', which has data important only
 # for pre-1970 timestamps and so is out of scope for tzdb proper.
 # Link	TARGET			LINK-NAME
 Link	Africa/Abidjan		Africa/Accra
 Link	Africa/Nairobi		Africa/Addis_Ababa
 Link	Africa/Nairobi		Africa/Asmara
 Link	Africa/Nairobi		Africa/Asmera
 Link	Africa/Abidjan		Africa/Bamako
 Link	Africa/Lagos		Africa/Bangui
 Link	Africa/Abidjan		Africa/Banjul
 Link	Africa/Maputo		Africa/Blantyre
 Link	Africa/Lagos		Africa/Brazzaville
 Link	Africa/Maputo		Africa/Bujumbura
 Link	Africa/Abidjan		Africa/Conakry
 Link	Africa/Abidjan		Africa/Dakar
 Link	Africa/Nairobi		Africa/Dar_es_Salaam
 Link	Africa/Nairobi		Africa/Djibouti
 Link	Africa/Lagos		Africa/Douala
 Link	Africa/Abidjan		Africa/Freetown
 Link	Africa/Maputo		Africa/Gaborone
 Link	Africa/Maputo		Africa/Harare
 Link	Africa/Nairobi		Africa/Kampala
 Link	Africa/Maputo		Africa/Kigali
 Link	Africa/Lagos		Africa/Kinshasa
 Link	Africa/Lagos		Africa/Libreville
 Link	Africa/Abidjan		Africa/Lome
 Link	Africa/Lagos		Africa/Luanda
 Link	Africa/Maputo		Africa/Lubumbashi
 Link	Africa/Maputo		Africa/Lusaka
 Link	Africa/Lagos		Africa/Malabo
 Link	Africa/Johannesburg	Africa/Maseru
 Link	Africa/Johannesburg	Africa/Mbabane
 Link	Africa/Nairobi		Africa/Mogadishu
 Link	Africa/Lagos		Africa/Niamey
 Link	Africa/Abidjan		Africa/Nouakchott
 Link	Africa/Abidjan		Africa/Ouagadougou
 Link	Africa/Lagos		Africa/Porto-Novo
 Link	Africa/Abidjan		Africa/Timbuktu
 Link	America/Puerto_Rico	America/Anguilla
 Link	America/Puerto_Rico	America/Antigua
 Link	America/Argentina/Catamarca	America/Argentina/ComodRivadavia
 Link	America/Puerto_Rico	America/Aruba
 Link	America/Panama		America/Atikokan
 Link	America/Adak		America/Atka
 Link	America/Puerto_Rico	America/Blanc-Sablon
 Link	America/Argentina/Buenos_Aires	America/Buenos_Aires
 Link	America/Argentina/Catamarca	America/Catamarca
-Link	America/Atikokan	America/Coral_Harbour
+Link	America/Panama		America/Cayman
 Link	America/Panama		America/Coral_Harbour
 Link	America/Argentina/Cordoba	America/Cordoba
 Link	America/Phoenix		America/Creston
 Link	America/Puerto_Rico	America/Curacao
 Link	America/Puerto_Rico	America/Dominica
 Link	America/Tijuana		America/Ensenada
 Link	America/Indiana/Indianapolis	America/Fort_Wayne
 Link	America/Nuuk		America/Godthab
 Link	America/Puerto_Rico	America/Grenada
 Link	America/Puerto_Rico	America/Guadeloupe
 Link	America/Indiana/Indianapolis	America/Indianapolis
 Link	America/Argentina/Jujuy	America/Jujuy
 Link	America/Indiana/Knox	America/Knox_IN
 Link	America/Puerto_Rico	America/Kralendijk
 Link	America/Kentucky/Louisville	America/Louisville
 Link	America/Puerto_Rico	America/Lower_Princes
 Link	America/Puerto_Rico	America/Marigot
 Link	America/Argentina/Mendoza	America/Mendoza
 Link	America/Toronto		America/Montreal
 Link	America/Puerto_Rico	America/Montserrat
 Link	America/Toronto		America/Nassau
 Link	America/Puerto_Rico	America/Port_of_Spain
 Link	America/Rio_Branco	America/Porto_Acre
 Link	America/Argentina/Cordoba	America/Rosario
 Link	America/Tijuana		America/Santa_Isabel
 Link	America/Denver		America/Shiprock
-Link	America/Port_of_Spain	America/Virgin
+Link	America/Puerto_Rico	America/St_Barthelemy
 Link	America/Puerto_Rico	America/St_Kitts
 Link	America/Puerto_Rico	America/St_Lucia
 Link	America/Puerto_Rico	America/St_Thomas
 Link	America/Puerto_Rico	America/St_Vincent
 Link	America/Puerto_Rico	America/Tortola
 Link	America/Puerto_Rico	America/Virgin
 Link	Pacific/Port_Moresby	Antarctica/DumontDUrville
 Link	Pacific/Auckland	Antarctica/McMurdo
 Link	Pacific/Auckland	Antarctica/South_Pole
 Link	Asia/Riyadh		Antarctica/Syowa
 Link	Europe/Oslo		Arctic/Longyearbyen
 Link	Asia/Riyadh		Asia/Aden
 Link	Asia/Ashgabat		Asia/Ashkhabad
 Link	Asia/Qatar		Asia/Bahrain
 Link	Asia/Kolkata		Asia/Calcutta
 Link	Asia/Shanghai		Asia/Chongqing
 Link	Asia/Shanghai		Asia/Chungking
 Link	Asia/Dhaka		Asia/Dacca
 Link	Asia/Shanghai		Asia/Harbin
 Link	Europe/Istanbul		Asia/Istanbul
 Link	Asia/Urumqi		Asia/Kashgar
 Link	Asia/Kathmandu		Asia/Katmandu
 Link	Asia/Riyadh		Asia/Kuwait
 Link	Asia/Macau		Asia/Macao
 Link	Asia/Dubai		Asia/Muscat
 Link	Asia/Bangkok		Asia/Phnom_Penh
 Link	Asia/Yangon		Asia/Rangoon
 Link	Asia/Ho_Chi_Minh	Asia/Saigon
 Link	Asia/Jerusalem		Asia/Tel_Aviv
 Link	Asia/Thimphu		Asia/Thimbu
 Link	Asia/Makassar		Asia/Ujung_Pandang
 Link	Asia/Ulaanbaatar	Asia/Ulan_Bator
 Link	Asia/Bangkok		Asia/Vientiane
 Link	Atlantic/Faroe		Atlantic/Faeroe
-Link	Europe/Oslo		Atlantic/Jan_Mayen
+Link	Europe/Berlin		Atlantic/Jan_Mayen
 Link	Africa/Abidjan		Atlantic/St_Helena
 Link	Australia/Sydney	Australia/ACT
 Link	Australia/Sydney	Australia/Canberra
 Link	Australia/Hobart	Australia/Currie
@ -81,7 +152,22 @@ Link	Africa/Cairo		Egypt
 Link	Europe/Dublin		Eire
 Link	Etc/UTC			Etc/UCT
 Link	Europe/London		Europe/Belfast
 Link	Europe/Prague		Europe/Bratislava
 Link	Europe/Zurich		Europe/Busingen
 Link	Europe/London		Europe/Guernsey
 Link	Europe/London		Europe/Isle_of_Man
 Link	Europe/London		Europe/Jersey
 Link	Europe/Belgrade		Europe/Ljubljana
 Link	Europe/Helsinki		Europe/Mariehamn
 Link	Asia/Nicosia		Europe/Nicosia
 Link	Europe/Belgrade		Europe/Podgorica
 Link	Europe/Rome		Europe/San_Marino
 Link	Europe/Belgrade		Europe/Sarajevo
 Link	Europe/Belgrade		Europe/Skopje
 Link	Europe/Chisinau		Europe/Tiraspol
 Link	Europe/Zurich		Europe/Vaduz
 Link	Europe/Rome		Europe/Vatican
 Link	Europe/Belgrade		Europe/Zagreb
 Link	Europe/London		GB
 Link	Europe/London		GB-Eire
 Link	Etc/GMT			GMT+0
@ -90,6 +176,9 @@ Link	Etc/GMT			GMT0
 Link	Etc/GMT			Greenwich
 Link	Asia/Hong_Kong		Hongkong
 Link	Atlantic/Reykjavik	Iceland
 Link	Africa/Nairobi		Indian/Antananarivo
 Link	Africa/Nairobi		Indian/Comoro
 Link	Africa/Nairobi		Indian/Mayotte
 Link	Asia/Tehran		Iran
 Link	Asia/Jerusalem		Israel
 Link	America/Jamaica		Jamaica
@ -103,8 +192,11 @@ Link	Pacific/Auckland	NZ
 Link	Pacific/Chatham		NZ-CHAT
 Link	America/Denver		Navajo
 Link	Asia/Shanghai		PRC
 Link	Pacific/Kanton		Pacific/Enderbury
 Link	Pacific/Honolulu	Pacific/Johnston
 Link	Pacific/Pago_Pago	Pacific/Midway
 Link	Pacific/Pohnpei		Pacific/Ponape
 Link	Pacific/Guam		Pacific/Saipan
 Link	Pacific/Pago_Pago	Pacific/Samoa
 Link	Pacific/Chuuk		Pacific/Truk
 Link	Pacific/Chuuk		Pacific/Yap
--- a/contrib/tzdata/backzone
+++ b/contrib/tzdata/backzone
@ -68,6 +68,91 @@
 #
 # As explained in the zic man page, the zone columns are:
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # and the rule columns are:
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # Ghana
 # From P Chan (2020-11-20):
 # Interpretation Amendment Ordinance, 1915 (No.24 of 1915) [1915-11-02]
 # Ordinances of the Gold Coast, Ashanti, Northern Territories 1915, p 69-71
 # https://books.google.com/books?id=ErA-AQAAIAAJ&pg=PA70
 # This Ordinance added "'Time' shall mean Greenwich Mean Time" to the
 # Interpretation Ordinance, 1876.
 #
 # Determination of the Time Ordinance, 1919 (No. 18 of 1919) [1919-11-24]
 # Ordinances of the Gold Coast, Ashanti, Northern Territories 1919, p 75-76
 # https://books.google.com/books?id=MbA-AQAAIAAJ&pg=PA75
 # This Ordinance removed the previous definition of time and introduced DST.
 #
 # Time Determination Ordinance (Cap. 214)
 # The Laws of the Gold Coast (including Togoland Under British Mandate)
 # Vol. II (1937), p 2328
 # https://books.google.com/books?id=Z7M-AQAAIAAJ&pg=PA2328
 # Revised edition of the 1919 Ordinance.
 #
 # Time Determination (Amendment) Ordinance, 1940 (No. 9 of 1940) [1940-04-06]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1940, p 22
 # https://books.google.com/books?id=1ao-AQAAIAAJ&pg=PA22
 # This Ordinance changed the forward transition from September to May.
 #
 # Defence (Time Determination Ordinance Amendment) Regulations, 1942
 # (Regulations No. 6 of 1942) [1942-01-31, commenced on 1942-02-08]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1942, p 48
 # https://books.google.com/books?id=Das-AQAAIAAJ&pg=PA48
 # These regulations advanced the [standard] time by thirty minutes.
 #
 # Defence (Time Determination Ordinance Amendment (No.2)) Regulations,
 # 1942 (Regulations No. 28 of 1942) [1942-04-25]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1942, p 87
 # https://books.google.com/books?id=Das-AQAAIAAJ&pg=PA87
 # These regulations abolished DST and changed the time to GMT+0:30.
 #
 # Defence (Revocation) (No.4) Regulations, 1945 (Regulations No. 45 of
 # 1945) [1945-10-24, commenced on 1946-01-06]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1945, p 256
 # https://books.google.com/books?id=9as-AQAAIAAJ&pg=PA256
 # These regulations revoked the previous two sets of Regulations.
 #
 # Time Determination (Amendment) Ordinance, 1945 (No. 18 of 1945) [1946-01-06]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1945, p 69
 # https://books.google.com/books?id=9as-AQAAIAAJ&pg=PA69
 # This Ordinance abolished DST.
 #
 # Time Determination (Amendment) Ordinance, 1950 (No. 26 of 1950) [1950-07-22]
 # Annual Volume of the Laws of the Gold Coast:
 # Containing All Legislation Enacted During Year 1950, p 35
 # https://books.google.com/books?id=e60-AQAAIAAJ&pg=PA35
 # This Ordinance restored DST but with thirty minutes offset.
 #
 # Time Determination Ordinance (Cap. 264)
 # The Laws of the Gold Coast, Vol. V (1954), p 380
 # https://books.google.com/books?id=Mqc-AQAAIAAJ&pg=PA380
 # Revised edition of the Time Determination Ordinance.
 #
 # Time Determination (Amendment) Ordinance, 1956 (No. 21 of 1956) [1956-08-29]
 # Annual Volume of the Ordinances of the Gold Coast Enacted During the
 # Year 1956, p 83
 # https://books.google.com/books?id=VLE-AQAAIAAJ&pg=PA83
 # This Ordinance abolished DST.
 Rule	Ghana	1919	only	-	Nov	24	0:00	0:20	+0020
 Rule	Ghana	1920	1942	-	Jan	 1	2:00	0	GMT
 Rule	Ghana	1920	1939	-	Sep	 1	2:00	0:20	+0020
 Rule	Ghana	1940	1941	-	May	 1	2:00	0:20	+0020
 Rule	Ghana	1950	1955	-	Sep	 1	2:00	0:30	+0030
 Rule	Ghana	1951	1956	-	Jan	 1	2:00	0	GMT
 Zone	Africa/Accra	-0:00:52 -	LMT	1915 Nov  2
 			 0:00	Ghana	%s	1942 Feb  8
 			 0:30	-	+0030	1946 Jan  6
 			 0:00	Ghana	%s
 # Ethiopia
 # From Paul Eggert (2014-07-31):
@ -101,14 +186,36 @@ Zone	Africa/Bamako	-0:32:00 -	LMT	1912
 Zone	Africa/Bangui	1:14:20	-	LMT	1912
 			1:00	-	WAT
-# Gambia
+# The Gambia
 # From P Chan (2020-12-09):
 # Standard time of GMT-1 was adopted on 1933-04-01.  On 1942-02-01, GMT was
 # adopted as a war time measure.  This was made permanent in 1946.
 #
 # Interpretation Ordinance, 1914 (No. 12 of 1914) [1914-09-29]
 # Interpretation Ordinance, 1933 (No. 10 of 1933) [1933-03-31]
 # Notice No. 5 of 1942, Colony of the Gambia Government Gazette, Vol. LIX,
 # No.2, 1942-01-15, p 2
 # Interpretation (Amendment) Ordinance, 1946 (No. 3 of 1946) [1946-07-15]
 Zone	Africa/Banjul	-1:06:36 -	LMT	1912
-			-1:06:36 -	BMT	1935 # Banjul Mean Time
+			-1:06:36 -	BMT	1933 Apr  1 # Banjul Mean Time
-			-1:00	-	-01	1964
+			-1:00	-	-01	1942 Feb  1  0:00
 			 0:00	-	GMT
 # Malawi
-Zone	Africa/Blantyre	2:20:00 -	LMT	1903 Mar
+# From P Chan (2020-12-09):
 # In 1911, Zomba mean time was adopted as the legal time of Nyasaland.  In
 # 1914, Zomba mean time switched from GMT+2:21:10 to GMT+2:21. On 1925-07-01,
 # GMT+2 was adopted.
 #
 # Interpretation and General Clauses Ordinance, 1911 (No. 12 of 1911)
 # [1911-07-24]
 # Notice No. 124 of 1914, 1914-06-30, The Nyasaland Government Gazette, Vol.
 # XXI, No. 8, 1914-06-30, p 122
 # Interpretation and General Clauses (Amendment) Ordinance, 1925 (No. 3 of
 # 1925) [1925-04-02]
 Zone	Africa/Blantyre	2:20:00 -	LMT	1911 Jul 24
 			2:21:10	-	ZMT	1914 Jun 30 # Zomba Mean Time
 			2:21	-	ZMT	1925 Jul  1
 			2:00	-	CAT
 # Republic of the Congo
@ -145,19 +252,48 @@ Zone	Africa/Djibouti	2:52:36 -	LMT	1911 Jul
 Zone	Africa/Douala	0:38:48	-	LMT	1912
 			1:00	-	WAT
 # Sierra Leone
-# From Paul Eggert (2014-08-12):
+# From P Chan (2020-12-09):
-# The following table is from Shanks & Pottenger, but it can't be right.
+# Standard time of GMT-1 was adopted on 1913-07-01.  Twenty minutes of DST was
-# Whitman gives Mar 31 - Aug 31 for 1931 on.
+# introduce[d] in 1932 and was suspended in 1939.  In 1941, GMT was adopted by
-# The International Hydrographic Bulletin, 1932-33, p 63 says that
+# Defence Regulations.  This was made permanent in 1946.
-# Sierra Leone would advance its clocks by 20 minutes on 1933-10-01.
+#
-# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
+# Government Notice No. 121 of 1913, 1913-06-06, Sierra Leone Royal Gazette,
-Rule	SL	1935	1942	-	Jun	 1	0:00	0:40	-0020
+# Vol. XLIV, No. 1384, 1913-06-14, p 347
-Rule	SL	1935	1942	-	Oct	 1	0:00	0	-01
+# Alteration of Time Ordinance, 1932 (No. 34 of 1932) [1932-12-01]
-Rule	SL	1957	1962	-	Jun	 1	0:00	1:00	+01
+# Alteration of Time (Amendment) Ordinance, 1938 (No. 25 of 1938) [1938-11-24]
-Rule	SL	1957	1962	-	Sep	 1	0:00	0	GMT
+# Defence Regulations (No. 9), 1939 (Regulations No. 9 of 1939), 1939-09-05
 # Defence Regulations (No. 11), 1939 (Regulations No. 11 of 1939), 1939-09-27
 # Defence (Amendment) (No. 17) Regulations, 1941 (Public Notice No. 157 of
 # 1941), 1914-12-04
 # Alteration of Time (Amendment) Ordinance, 1946 (No. 2 of 1946) [1946-02-07]
 # From Tim Parenti (2021-03-02), per P Chan (2021-02-25):
 # For Sierra Leone in 1957-1962, the standard time was defined in the
 # Alteration of Time Ordinance, 1932 (as amended in 1946, renamed to Local Time
 # Ordinance in 1960 and Local Time Act in 1961). It was unamended throughout
 # that period.  See references to "Time" in the Alphabetical Index of the
 # Legislation in force on the 31st day of December,
 #   1957: https://books.google.com/books?id=lvQ-AQAAIAAJ&pg=RA2-PA49
 #   1958: https://books.google.com/books?id=4fQ-AQAAIAAJ&pg=RA2-PA50
 #   1959: https://books.google.com/books?id=p_U-AQAAIAAJ&pg=RA2-PA55
 #   1960: https://books.google.com/books?id=JPY-AQAAIAAJ&pg=RA3-PA37
 #   1961: https://books.google.com/books?id=7vY-AQAAIAAJ&pg=RA3-PA41
 #   1962: https://books.google.com/books?id=W_c-AQAAIAAJ&pg=RA3-PA44
 #   1963: https://books.google.com/books?id=9vk-AQAAIAAJ&pg=RA1-PA47
 #
 # Although Shanks & Pottenger had DST from Jun 1 00:00 to Sep 1 00:00 in this
 # period, many contemporaneous almanacs agree that it wasn't used:
 # https://mm.icann.org/pipermail/tz/2021-February/029866.html
 # Go with the above.
 Rule	SL	1932	only	-	Dec	 1	 0:00	0:20	-0040
 Rule	SL	1933	1938	-	Mar	31	24:00	0	-01
 Rule	SL	1933	1939	-	Aug	31	24:00	0:20	-0040
 Rule	SL	1939	only	-	May	31	24:00	0	-01
 Zone	Africa/Freetown	-0:53:00 -	LMT	1882
-			-0:53:00 -	FMT	1913 Jun # Freetown Mean Time
+			-0:53:00 -	FMT	1913 Jul  1 # Freetown MT
-			-1:00	SL	%s	1957
+			-1:00	SL	%s	1939 Sep  5
 			-1:00	-	-01	1941 Dec  6 24:00
 			 0:00	SL	GMT/+01
 # Botswana
@ -298,6 +434,85 @@ Zone	America/Aruba	-4:40:24 -	LMT	1912 Feb 12 # Oranjestad
 			-4:30	-	-0430	1965
 			-4:00	-	AST
 # Atikokan, Ontario
 # From Paul Eggert (1997-10-17):
 # Mark Brader writes that an article in the 1997-10-14 Toronto Star
 # says that Atikokan, Ontario currently does not observe DST,
 # but will vote on 11-10 whether to use EST/EDT.
 # He also writes that the Ontario Time Act (1990, Chapter T.9)
 # http://www.gov.on.ca/MBS/english/publications/statregs/conttext.html
 # says that Ontario east of 90W uses EST/EDT, and west of 90W uses CST/CDT.
 # Officially Atikokan is therefore on CST/CDT, and most likely this report
 # concerns a non-official time observed as a matter of local practice.
 #
 # From Paul Eggert (2000-10-02):
 # Matthews and Vincent (1998) write that Atikokan, Pickle Lake, and
 # New Osnaburgh observe CST all year, that Big Trout Lake observes
 # CST/CDT, and that Upsala and Shebandowan observe EST/EDT, all in
 # violation of the official Ontario rules.
 #
 # From Paul Eggert (2006-07-09):
 # Chris Walton (2006-07-06) mentioned an article by Stephanie MacLellan in the
 # 2005-07-21 Chronicle-Journal, which said:
 #
 #	The clocks in Atikokan stay set on standard time year-round.
 #	This means they spend about half the time on central time and
 #	the other half on eastern time.
 #
 #	For the most part, the system works, Mayor Dennis Brown said.
 #
 #	"The majority of businesses in Atikokan deal more with Eastern
 #	Canada, but there are some that deal with Western Canada," he
 #	said.  "I don't see any changes happening here."
 #
 # Walton also writes "Supposedly Pickle Lake and Mishkeegogamang
 # [New Osnaburgh] follow the same practice."
 # From Garry McKinnon (2006-07-14) via Chris Walton:
 # I chatted with a member of my board who has an outstanding memory
 # and a long history in Atikokan (and in the telecom industry) and he
 # can say for certain that Atikokan has been practicing the current
 # time keeping since 1952, at least.
 # From Paul Eggert (2006-07-17):
 # Shanks & Pottenger say that Atikokan has agreed with Rainy River
 # ever since standard time was introduced, but the information from
 # McKinnon sounds more authoritative.  For now, assume that Atikokan
 # switched to EST immediately after WWII era daylight saving time
 # ended.  This matches the old (less-populous) America/Coral_Harbour
 # entry since our cutoff date of 1970, so we can move
 # America/Coral_Harbour to the 'backward' file.
 Zone America/Atikokan	-6:06:28 -	LMT	1895
 			-6:00	Canada	C%sT	1940 Sep 29
 			-6:00	1:00	CDT	1942 Feb  9  2:00s
 			-6:00	Canada	C%sT	1945 Sep 30  2:00
 			-5:00	-	EST
 # Quebec east of Natashquan
 # From Paul Eggert (2021-05-09):
 # H. David Matthews and Mary Vincent's map
 # "It's about TIME", _Canadian Geographic_ (September-October 1998)
 # http://www.canadiangeographic.ca/Magazine/SO98/alacarte.asp
 # says that Quebec east of the -63 meridian is supposed to observe
 # AST, but residents as far east as Natashquan use EST/EDT, and
 # residents east of Natashquan use AST.
 # The Quebec department of justice writes in
 # "The situation in Minganie and Basse-Côte-Nord"
 # https://www.justice.gouv.qc.ca/en/department/ministre/functions-and-responsabilities/legal-time-in-quebec/the-situation-in-minganie-and-basse-cote-nord/
 # that the coastal strip from just east of Natashquan to Blanc-Sablon
 # observes Atlantic standard time all year round.
 # This common practice was codified into law as of 2007; see Legal Time Act,
 # CQLR c T-5.1 <http://legisquebec.gouv.qc.ca/en/ShowDoc/cs/T-5.1>.
 # For lack of better info, guess this practice began around 1970, contra to
 # Shanks & Pottenger who have this region observing AST/ADT.
 Zone America/Blanc-Sablon -3:48:28 -	LMT	1884
 			-4:00	Canada	A%sT	1970
 			-4:00	-	AST
 # Cayman Is
 Zone	America/Cayman	-5:25:32 -	LMT	1890     # Georgetown
 			-5:07:10 -	KMT	1912 Feb # Kingston Mean Time
@ -318,6 +533,85 @@ Zone America/Coral_Harbour -5:32:40 -	LMT	1884
 			-5:00	NT_YK	E%sT	1946
 			-5:00	-	EST
 # From Chris Walton (2011-12-01):
 # There are two areas within the Canadian province of British Columbia
 # that do not currently observe daylight saving:
 # a) The Creston Valley (includes the town of Creston and surrounding area)
 # b) The eastern half of the Peace River Regional District
 # (includes the cities of Dawson Creek and Fort St. John)
 # Earlier this year I stumbled across a detailed article about the time
 # keeping history of Creston; it was written by Tammy Hardwick who is the
 # manager of the Creston & District Museum. The article was written in May 2009.
 # http://www.ilovecreston.com/?p=articles&t=spec&ar=260
 # According to the article, Creston has not changed its clocks since June 1918.
 # i.e. Creston has been stuck on UT-7 for 93 years.
 # Dawson Creek, on the other hand, changed its clocks as recently as April 1972.
 # Unfortunately the exact date for the time change in June 1918 remains
 # unknown and will be difficult to ascertain.  I e-mailed Tammy a few months
 # ago to ask if Sunday June 2 was a reasonable guess.  She said it was just
 # as plausible as any other date (in June).  She also said that after writing
 # the article she had discovered another time change in 1916; this is the
 # subject of another article which she wrote in October 2010.
 # http://www.creston.museum.bc.ca/index.php?module=comments&uop=view_comment&cm+id=56
 # Here is a summary of the three clock change events in Creston's history:
 # 1. 1884 or 1885: adoption of Mountain Standard Time (GMT-7)
 # Exact date unknown
 # 2. Oct 1916: switch to Pacific Standard Time (GMT-8)
 # Exact date in October unknown; Sunday October 1 is a reasonable guess.
 # 3. June 1918: switch to Pacific Daylight Time (GMT-7)
 # Exact date in June unknown; Sunday June 2 is a reasonable guess.
 # note 1:
 # On Oct 27/1918 when daylight saving ended in the rest of Canada,
 # Creston did not change its clocks.
 # note 2:
 # During WWII when the Federal Government legislated a mandatory clock change,
 # Creston did not oblige.
 # note 3:
 # There is no guarantee that Creston will remain on Mountain Standard Time
 # (UTC-7) forever.
 # The subject was debated at least once this year by the town Council.
 # http://www.bclocalnews.com/kootenay_rockies/crestonvalleyadvance/news/116760809.html
 # During a period WWII, summer time (Daylight saying) was mandatory in Canada.
 # In Creston, that was handled by shifting the area to PST (-8:00) then applying
 # summer time to cause the offset to be -7:00, the same as it had been before
 # the change.  It can be argued that the timezone abbreviation during this
 # period should be PDT rather than MST, but that doesn't seem important enough
 # (to anyone) to further complicate the rules.
 # The transition dates (and times) are guesses.
 Zone America/Creston	-7:46:04 -	LMT	1884
 			-7:00	-	MST	1916 Oct 1
 			-8:00	-	PST	1918 Jun 2
 			-7:00	-	MST
 # Curaçao
 # Milne gives 4:35:46.9 for Curaçao mean time; round to nearest.
 #
 # From Paul Eggert (2006-03-22):
 # Shanks & Pottenger say that The Bottom and Philipsburg have been at
 # -4:00 since standard time was introduced on 1912-03-02; and that
 # Kralendijk and Rincon used Kralendijk Mean Time (-4:33:08) from
 # 1912-02-02 to 1965-01-01.  The former is dubious, since S&P also say
 # Saba Island has been like Curaçao.
 # This all predates our 1970 cutoff, though.
 #
 # By July 2007 Curaçao and St Maarten are planned to become
 # associated states within the Netherlands, much like Aruba;
 # Bonaire, Saba and St Eustatius would become directly part of the
 # Netherlands as Kingdom Islands.  This won't affect their time zones
 # though, as far as we know.
 #
 Zone	America/Curacao	-4:35:47 -	LMT	1912 Feb 12 # Willemstad
 			-4:30	-	-0430	1965
 			-4:00	-	AST
 Link	America/Curacao	America/Kralendijk
 Link	America/Curacao	America/Lower_Princes
 # Dominica
 Zone America/Dominica	-4:05:36 -	LMT	1911 Jul  1  0:01 # Roseau
 			-4:00	-	AST
@ -340,6 +634,7 @@ Zone	America/Grenada	-4:07:00 -	LMT	1911 Jul # St George's
 Zone America/Guadeloupe	-4:06:08 -	LMT	1911 Jun  8 # Pointe-à-Pitre
 			-4:00	 -	AST
 # Canada
 #
 # From Paul Eggert (2015-03-24):
@ -351,7 +646,6 @@ Zone America/Guadeloupe	-4:06:08 -	LMT	1911 Jun  8 # Pointe-à-Pitre
 # Pottenger data.  The post-1970 entries have been corrected, but the
 # pre-1970 entries are unchecked and probably have errors.
 #
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Mont	1917	only	-	Mar	25	2:00	1:00	D
 Rule	Mont	1917	only	-	Apr	24	0:00	0	S
 Rule	Mont	1919	only	-	Mar	31	2:30	1:00	D
@ -387,6 +681,48 @@ Zone America/Montreal	-4:54:16 -	LMT	1884
 Zone America/Montserrat	-4:08:52 -	LMT	1911 Jul  1  0:01 # Cork Hill
 			-4:00	-	AST
 # The Bahamas
 #
 # For 1899 Milne gives -5:09:29.5; round that.
 #
 # From P Chan (2020-11-27, corrected on 2020-12-02):
 # There were two periods of DST observed in 1942-1945: 1942-05-01
 # midnight to 1944-12-31 midnight and 1945-02-01 to 1945-10-17 midnight.
 # "midnight" should mean 24:00 from the context.
 #
 # War Time Order 1942 [1942-05-01] and War Time (No. 2) Order 1942  [1942-09-29]
 # Appendix to the Statutes of 7 George VI. and the Year 1942. p 34, 43
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA3-PA34
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA3-PA43
 #
 # War Time Order 1943 [1943-03-31] and War Time Order 1944 [1943-12-29]
 # Appendix to the Statutes of 8 George VI. and the Year 1943. p 9-10, 28-29
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA4-PA9
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA4-PA28
 #
 # War Time Order 1945 [1945-01-31] and the Order which revoke War Time Order
 # 1945 [1945-10-16] Appendix to the Statutes of 9 George VI. and the Year
 # 1945. p 160, 247-248
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA6-PA160
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA6-PA247
 #
 # From Sue Williams (2006-12-07):
 # The Bahamas announced about a month ago that they plan to change their DST
 # rules to sync with the U.S. starting in 2007....
 # http://www.jonesbahamas.com/?c=45&a=10412
 Rule	Bahamas	1942	only	-	May	 1	24:00	1:00	W
 Rule	Bahamas	1944	only	-	Dec	31	24:00	0	S
 Rule	Bahamas	1945	only	-	Feb	 1	0:00	1:00	W
 Rule	Bahamas	1945	only	-	Aug	14	23:00u	1:00	P # Peace
 Rule	Bahamas	1945	only	-	Oct	17	24:00	0	S
 Rule	Bahamas	1964	1975	-	Oct	lastSun	2:00	0	S
 Rule	Bahamas	1964	1975	-	Apr	lastSun	2:00	1:00	D
 Zone	America/Nassau	-5:09:30 -	LMT	1912 Mar 2
 			-5:00	Bahamas	E%sT	1976
 			-5:00	US	E%sT
 # United States
 #
 # From Paul Eggert (2018-03-18):
@ -411,6 +747,13 @@ Zone America/Montserrat	-4:08:52 -	LMT	1911 Jul  1  0:01 # Cork Hill
 # https://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=DS19470110
 # front page reports on end.
 # Trinidad and Tobago
 Zone America/Port_of_Spain -4:06:04 -	LMT	1912 Mar 2
 			-4:00	-	AST
 Link America/Port_of_Spain America/Marigot
 Link America/Port_of_Spain America/St_Barthelemy
 Link America/Port_of_Spain America/Virgin
 # Argentina
 # This entry was intended for the following areas, but has been superseded by
 # more detailed zones.
@ -434,7 +777,7 @@ Zone America/St_Lucia	-4:04:00 -	LMT	1890 # Castries
 			-4:04:00 -	CMT	1912 # Castries Mean Time
 			-4:00	-	AST
-# Virgin Is
+# US Virgin Is
 Zone America/St_Thomas	-4:19:44 -	LMT	1911 Jul # Charlotte Amalie
 			-4:00	-	AST
@ -447,11 +790,36 @@ Zone America/St_Vincent	-4:04:56 -	LMT	1890 # Kingstown
 Zone America/Tortola	-4:18:28 -	LMT	1911 Jul # Road Town
 			-4:00	-	AST
 # Dumont d'Urville, Île des Pétrels, -6640+14001, since 1956-11
 # <https://en.wikipedia.org/wiki/Dumont_d'Urville_Station> (2005-12-05)
 #
 # Another base at Port-Martin, 50km east, began operation in 1947.
 # It was destroyed by fire on 1952-01-14.
 #
 Zone Antarctica/DumontDUrville 0 -	-00	1947
 			10:00	-	+10	1952 Jan 14
 			0	-	-00	1956 Nov
 			10:00	-	+10
 # McMurdo, Ross Island, since 1955-12
 Zone Antarctica/McMurdo	0	-	-00	1956
 			12:00	NZ	NZ%sT
 Link Antarctica/McMurdo Antarctica/South_Pole
 # Syowa, Antarctica
 #
 # From Hideyuki Suzuki (1999-02-06):
 # In all Japanese stations, +0300 is used as the standard time.
 #
 # Syowa station, which is the first antarctic station of Japan,
 # was established on 1957-01-29.  Since Syowa station is still the main
 # station of Japan, it's appropriate for the principal location.
 Zone Antarctica/Syowa	0	-	-00	1957 Jan 29
 			3:00	-	+03
 # See:
 # NIPR Antarctic Research Activities (1999-08-17)
 # http://www.nipr.ac.jp/english/ara01.html
 # Yemen
 # Milne says 2:59:54 was the meridian of the saluting battery at Aden,
 # and that Yemen was at 1:55:56, the meridian of the Hagia Sophia.
@ -711,6 +1079,8 @@ Zone	Europe/Skopje	1:25:44	-	LMT	1884
 			1:00	-	CET	1982 Nov 27
 			1:00	EU	CE%sT
 # Moldova / Transnistria
 Zone	Europe/Tiraspol	1:58:32	-	LMT	1880
 			1:55	-	CMT	1918 Feb 15 # Chisinau MT
@ -749,10 +1119,22 @@ Zone	Indian/Comoro	2:53:04 -	LMT	1911 Jul # Moroni, Gran Comoro
 Zone	Indian/Mayotte	3:00:56 -	LMT	1911 Jul # Mamoutzou
 			3:00	-	EAT
-# US minor outlying islands
+# Phoenix Islands, Kiribati
 # From Paul Eggert (2021-05-27):
 # Enderbury was inhabited 1860/1880s to mine guano, and 1938-03-06/1942-02-09
 # for aviation (ostensibly commercial, but military uses foreseen).
 # The 19th-century dates are approximate.  See Pacific/Kanton for
 # the currently-inhabited representative for this timezone.
 Zone Pacific/Enderbury	0	-	-00	1860
 			-11:24:20 -	LMT	1885
 			0	-	-00	1938 Mar  6
 			-12:00	-	-12	1942 Feb  9
 			0	-	-00
 # Johnston
 Zone Pacific/Johnston	-10:00	-	HST
-# US minor outlying islands
+# Midway
 #
 # From Mark Brader (2005-01-23):
 # [Fallacies and Fantasies of Air Transport History, by R.E.G. Davies,
@ -775,3 +1157,7 @@ Zone Pacific/Saipan	-14:17:00 -	LMT	1844 Dec 31
 			 9:00	-	+09	1969 Oct
 			10:00	-	+10	2000 Dec 23
 			10:00	-	ChST	# Chamorro Standard Time
 # Local Variables:
 # coding: utf-8
 # End:
--- a/contrib/tzdata/checktab.awk
+++ b/contrib/tzdata/checktab.awk
@ -58,11 +58,12 @@ BEGIN {
 				zone_table, zone_NR >>"/dev/stderr"
 			status = 1
 		}
-		split($1, cca, /,/)
+		ccs = input_ccs[zone_NR] = $1
 		cc = cca[1]
 		coordinates = $2
 		tz = $3
-		comments = $4
+		comments = input_comments[zone_NR] = $4
 		split(ccs, cca, /,/)
 		cc = cca[1]
 		# Don't complain about a special case for Crimea in zone.tab.
 		# FIXME: zone.tab should be removed, since it is obsolete.
@ -77,12 +78,9 @@ BEGIN {
 		cc0 = cc
 		tz0 = tz
 		tztab[tz] = 1
 		tz2comments[tz] = comments
 		tz2NR[tz] = zone_NR
 		for (i in cca) {
 		    cc = cca[i]
 		    cctz = cc tz
 		    cctztab[cctz] = 1
 		    if (cc2name[cc]) {
 			cc_used[cc]++
 		    } else {
@ -99,27 +97,27 @@ BEGIN {
 		}
 	}
-	for (cctz in cctztab) {
+	for (i = 1; i <= zone_NR; i++) {
-		cc = substr (cctz, 1, 2)
+	  ccs = input_ccs[i]
-		tz = substr (cctz, 3)
+	  if (!ccs) continue
-		if (1 < cc_used[cc]) {
+	  comments = input_comments[i]
-			comments_needed[tz] = cc
+	  split(ccs, cca, /,/)
-		}
+	  used_max = 0
-	}
+          for (j in cca) {
-	for (cctz in cctztab) {
+	    cc = cca[j]
-	  cc = substr (cctz, 1, 2)
+	    if (used_max < cc_used[cc]) {
-	  tz = substr (cctz, 3)
+	      used_max = cc_used[cc]
-	  if (!comments_needed[tz] && tz2comments[tz]) {
+	    }
 	  }
 	  if (used_max <= 1 && comments) {
 	    printf "%s:%d: unnecessary comment '%s'\n", \
-		zone_table, tz2NR[tz], tz2comments[tz] \
+	      zone_table, i, comments \
-		>>"/dev/stderr"
+	      >>"/dev/stderr"
-	    tz2comments[tz] = 0
+	    status = 1
-	    status = 1
+	  } else if (1 < cc_used[cc] && !comments) {
-	  } else if (comments_needed[tz] && !tz2comments[tz]) {
+	    printf "%s:%d: missing comment for %s\n", \
-	    printf "%s:%d: missing comment for %s\n", \
+	      zone_table, i, cc \
 	      zone_table, tz2NR[tz], comments_needed[tz] \
 	      >>"/dev/stderr"
 	    tz2comments[tz] = 1
 	    status = 1
 	  }
 	}
@ -149,8 +147,8 @@ $1 ~ /^#/ { next }
 		ruleUsed[$2] = 1
 		if ($3 ~ /%/) rulePercentUsed[$2] = 1
 	}
-	if (tz && tz ~ /\//) {
+	if (tz && tz ~ /\// && tz !~ /^Etc\//) {
-		if (!tztab[tz]) {
+		if (!tztab[tz] && FILENAME != "backward") {
 			printf "%s: no data for '%s'\n", zone_table, tz \
 				>>"/dev/stderr"
 			status = 1
@ -173,7 +171,7 @@ END {
 		}
 	}
 	for (tz in tztab) {
-		if (!zoneSeen[tz]) {
+		if (!zoneSeen[tz] && tz !~ /^Etc\//) {
 			printf "%s:%d: no Zone table for '%s'\n", \
 				zone_table, tz2NR[tz], tz >>"/dev/stderr"
 			status = 1
--- a/contrib/tzdata/europe
+++ b/contrib/tzdata/europe
@ -68,7 +68,6 @@
 #        0:00       GMT  BST  BDST  Greenwich, British Summer
 #        0:00       GMT  IST        Greenwich, Irish Summer
 #        0:00       WET  WEST WEMT  Western Europe
 #        0:19:32.13 AMT* NST*       Amsterdam, Netherlands Summer (1835-1937)
 #        1:00       BST             British Standard (1968-1971)
 #        1:00       IST  GMT        Irish Standard (1968-) with winter DST
 #        1:00       CET  CEST CEMT  Central Europe
@ -506,9 +505,6 @@ Zone	Europe/London	-0:01:15 -	LMT	1847 Dec  1  0:00s
 			 1:00	-	BST	1971 Oct 31  2:00u
 			 0:00	GB-Eire	%s	1996
 			 0:00	EU	GMT/BST
 Link	Europe/London	Europe/Jersey
 Link	Europe/London	Europe/Guernsey
 Link	Europe/London	Europe/Isle_of_Man
 # From Paul Eggert (2018-02-15):
 # In January 2018 we discovered that the negative SAVE values in the
@ -1307,9 +1303,8 @@ Zone	Europe/Helsinki	1:39:49 -	LMT	1878 May 31
 			1:39:49	-	HMT	1921 May    # Helsinki Mean Time
 			2:00	Finland	EE%sT	1983
 			2:00	EU	EE%sT
 # Åland Is
-Link	Europe/Helsinki	Europe/Mariehamn
+# See Europe/Helsinki.
 # France
@ -1505,8 +1500,7 @@ Zone	Europe/Berlin	0:53:28 -	LMT	1893 Apr
 # From Arthur David Olson (2012-03-03):
 # Büsingen and Zurich have shared clocks since 1970.
-
+# See Europe/Zurich.
 Link	Europe/Zurich	Europe/Busingen
 # Georgia
 # Please see the "asia" file for Asia/Tbilisi.
@ -1800,8 +1794,9 @@ Zone	Europe/Rome	0:49:56 -	LMT	1866 Dec 12
 			1:00	Italy	CE%sT	1980
 			1:00	EU	CE%sT
-Link	Europe/Rome	Europe/Vatican
+# Kosovo
-Link	Europe/Rome	Europe/San_Marino
+# See Europe/Belgrade.
 # Latvia
@ -1895,7 +1890,7 @@ Zone	Europe/Riga	1:36:34	-	LMT	1880
 # I could confirm from the paper that Liechtenstein did in fact follow
 # the same DST in 1941 and 1942 as Switzerland did.
-Link Europe/Zurich Europe/Vaduz
+# See Europe/Zurich.
 # Lithuania
@ -2150,6 +2145,10 @@ Zone	Europe/Monaco	0:29:32 -	LMT	1892 Jun  1
 # The data entries before 1945 are taken from
 # https://www.staff.science.uu.nl/~gent0113/wettijd/wettijd.htm
 # From Paul Eggert (2021-05-09):
 # I invented the abbreviations AMT for Amsterdam Mean Time and NST for
 # Netherlands Summer Time, used in the Netherlands from 1835 to 1937.
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Neth	1916	only	-	May	 1	0:00	1:00	NST	# Netherlands Summer Time
 Rule	Neth	1916	only	-	Oct	 1	0:00	0	AMT	# Amsterdam Mean Time
@ -2248,8 +2247,7 @@ Zone	Europe/Oslo	0:43:00 -	LMT	1895 Jan  1
 # Haudegen did not surrender to the Allies until September 1945.
 #
 # All these events predate our cutoff date of 1970, so use Europe/Oslo
-# for these regions.
+# for these regions; see 'backward'.
 Link	Europe/Oslo	Arctic/Longyearbyen
 # Poland
@ -2376,12 +2374,10 @@ Rule	Port	1943	1945	-	Aug	Sat>=25	22:00s	1:00	S
 Rule	Port	1944	1945	-	Apr	Sat>=21	22:00s	2:00	M
 Rule	Port	1946	only	-	Apr	Sat>=1	23:00s	1:00	S
 Rule	Port	1946	only	-	Oct	Sat>=1	23:00s	0	-
-Rule	Port	1947	1949	-	Apr	Sun>=1	 2:00s	1:00	S
+# Whitman says DST was not observed in 1950; go with Shanks & Pottenger.
 Rule	Port	1947	1949	-	Oct	Sun>=1	 2:00s	0	-
 # Shanks & Pottenger say DST was observed in 1950; go with Whitman.
 # Whitman gives Oct lastSun for 1952 on; go with Shanks & Pottenger.
-Rule	Port	1951	1965	-	Apr	Sun>=1	 2:00s	1:00	S
+Rule	Port	1947	1965	-	Apr	Sun>=1	 2:00s	1:00	S
-Rule	Port	1951	1965	-	Oct	Sun>=1	 2:00s	0	-
+Rule	Port	1947	1965	-	Oct	Sun>=1	 2:00s	0	-
 Rule	Port	1977	only	-	Mar	27	 0:00s	1:00	S
 Rule	Port	1977	only	-	Sep	25	 0:00s	0	-
 Rule	Port	1978	1979	-	Apr	Sun>=1	 0:00s	1:00	S
@ -3520,14 +3516,9 @@ Zone	Europe/Belgrade	1:22:00	-	LMT	1884
 # Shanks & Pottenger don't give as much detail, so go with Koželj.
 			1:00	-	CET	1982 Nov 27
 			1:00	EU	CE%sT
 Link Europe/Belgrade Europe/Ljubljana	# Slovenia
 Link Europe/Belgrade Europe/Podgorica	# Montenegro
 Link Europe/Belgrade Europe/Sarajevo	# Bosnia and Herzegovina
 Link Europe/Belgrade Europe/Skopje	# North Macedonia
 Link Europe/Belgrade Europe/Zagreb	# Croatia
 # Slovakia
-Link Europe/Prague Europe/Bratislava
+# See Europe/Prague.
 # Slovenia
 # See Europe/Belgrade.
@ -3683,6 +3674,9 @@ Zone	Atlantic/Canary	-1:01:36 -	LMT	1922 Mar # Las Palmas de Gran C.
 #
 # Source: The newspaper "Dagens Nyheter", 1916-10-01, page 7 upper left.
 # An extra-special abbreviation style is SET for Swedish Time (svensk
 # normaltid) 1879-1899, 3° west of the Stockholm Observatory.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Europe/Stockholm	1:12:12 -	LMT	1879 Jan  1
 			1:00:14	-	SET	1900 Jan  1 # Swedish Time
@ -3995,7 +3989,7 @@ Zone	Europe/Istanbul	1:55:52 -	LMT	1880
 			2:00	1:00	EEST	2015 Nov  8  1:00u
 			2:00	EU	EE%sT	2016 Sep  7
 			3:00	-	+03
-Link	Europe/Istanbul	Asia/Istanbul	# Istanbul is in both continents.
+# See the 'backward' file for Asia/Istanbul.
 # Ukraine
 #
--- a/contrib/tzdata/leap-seconds.list
+++ b/contrib/tzdata/leap-seconds.list
@ -204,10 +204,10 @@
 #	current -- the update time stamp, the data and the name of the file
 #	will not change.
 #
-#	Updated through IERS Bulletin C61
+#	Updated through IERS Bulletin C62
-#	File expires on:  28 December 2021
+#	File expires on:  28 June 2022
 #
-#@	3849638400
+#@	3865363200
 #
 2272060800	10	# 1 Jan 1972
 2287785600	11	# 1 Jul 1972
@ -252,4 +252,4 @@
 #	the hash line is also ignored in the
 #	computation.
 #
-#h 	2ab8253d d4380d28 75f01343 381504f8 8f8a4bfc
+#h 	599d45bf accd4b4f 8b60e46 49b623 7d13b825
--- a/contrib/tzdata/leapseconds
+++ b/contrib/tzdata/leapseconds
@ -72,11 +72,11 @@ Leap	2016	Dec	31	23:59:60	+	S
 # Any additional leap seconds will come after this.
 # This Expires line is commented out for now,
 # so that pre-2020a zic implementations do not reject this file.
-#Expires 2021	Dec	28	00:00:00
+#Expires 2022	Jun	28	00:00:00
 # POSIX timestamps for the data in this file:
 #updated 1467936000 (2016-07-08 00:00:00 UTC)
-#expires 1640649600 (2021-12-28 00:00:00 UTC)
+#expires 1656374400 (2022-06-28 00:00:00 UTC)
-#	Updated through IERS Bulletin C61
+#	Updated through IERS Bulletin C62
-#	File expires on:  28 December 2021
+#	File expires on:  28 June 2022
--- a/contrib/tzdata/northamerica
+++ b/contrib/tzdata/northamerica
@ -729,7 +729,11 @@ Zone America/Adak	 12:13:22 -	LMT	1867 Oct 19 12:44:35
 			-11:00	US	B%sT	1983 Oct 30  2:00
 			-10:00	US	AH%sT	1983 Nov 30
 			-10:00	US	H%sT
-# The following switches don't quite make our 1970 cutoff.
+# The following switches don't make our 1970 cutoff.
 #
 # Kiska observed Tokyo date and time during Japanese occupation from
 # 1942-06-06 to 1943-07-29, and similarly for Attu from 1942-06-07 to
 # 1943-05-29 (all dates American).  Both islands are now uninhabited.
 #
 # Shanks writes that part of southwest Alaska (e.g. Aniak)
 # switched from -11:00 to -10:00 on 1968-09-22 at 02:00,
@ -1593,24 +1597,7 @@ Zone America/Moncton	-4:19:08 -	LMT	1883 Dec  9
 # From Paul Eggert (2020-01-10):
 # See America/Toronto for most of Quebec, including Montreal.
 # See America/Halifax for the Îles de la Madeleine and the Listuguj reserve.
-#
+# See America/Puerto_Rico for east of Natashquan.
 # Matthews and Vincent (1998) also write that Quebec east of the -63
 # meridian is supposed to observe AST, but residents as far east as
 # Natashquan use EST/EDT, and residents east of Natashquan use AST.
 # The Quebec department of justice writes in
 # "The situation in Minganie and Basse-Côte-Nord"
 # https://www.justice.gouv.qc.ca/en/department/ministre/functions-and-responsabilities/legal-time-in-quebec/the-situation-in-minganie-and-basse-cote-nord/
 # that the coastal strip from just east of Natashquan to Blanc-Sablon
 # observes Atlantic standard time all year round.
 # This common practice was codified into law as of 2007; see Legal Time Act,
 # CQLR c T-5.1 <http://legisquebec.gouv.qc.ca/en/ShowDoc/cs/T-5.1>.
 # For lack of better info, guess this practice began around 1970, contra to
 # Shanks & Pottenger who have this region observing AST/ADT.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Blanc-Sablon -3:48:28 -	LMT	1884
 			-4:00	Canada	A%sT	1970
 			-4:00	-	AST
 # Ontario
@ -1649,54 +1636,6 @@ Zone America/Blanc-Sablon -3:48:28 -	LMT	1884
 # time became a comic failure in Orillia. Toronto Star 2017-07-08.
 # https://www.thestar.com/news/insight/2017/07/08/bold-attempt-at-daylight-saving-time-became-a-comic-failure-in-orillia.html
 # From Paul Eggert (1997-10-17):
 # Mark Brader writes that an article in the 1997-10-14 Toronto Star
 # says that Atikokan, Ontario currently does not observe DST,
 # but will vote on 11-10 whether to use EST/EDT.
 # He also writes that the Ontario Time Act (1990, Chapter T.9)
 # http://www.gov.on.ca/MBS/english/publications/statregs/conttext.html
 # says that Ontario east of 90W uses EST/EDT, and west of 90W uses CST/CDT.
 # Officially Atikokan is therefore on CST/CDT, and most likely this report
 # concerns a non-official time observed as a matter of local practice.
 #
 # From Paul Eggert (2000-10-02):
 # Matthews and Vincent (1998) write that Atikokan, Pickle Lake, and
 # New Osnaburgh observe CST all year, that Big Trout Lake observes
 # CST/CDT, and that Upsala and Shebandowan observe EST/EDT, all in
 # violation of the official Ontario rules.
 #
 # From Paul Eggert (2006-07-09):
 # Chris Walton (2006-07-06) mentioned an article by Stephanie MacLellan in the
 # 2005-07-21 Chronicle-Journal, which said:
 #
 #	The clocks in Atikokan stay set on standard time year-round.
 #	This means they spend about half the time on central time and
 #	the other half on eastern time.
 #
 #	For the most part, the system works, Mayor Dennis Brown said.
 #
 #	"The majority of businesses in Atikokan deal more with Eastern
 #	Canada, but there are some that deal with Western Canada," he
 #	said.  "I don't see any changes happening here."
 #
 # Walton also writes "Supposedly Pickle Lake and Mishkeegogamang
 # [New Osnaburgh] follow the same practice."
 # From Garry McKinnon (2006-07-14) via Chris Walton:
 # I chatted with a member of my board who has an outstanding memory
 # and a long history in Atikokan (and in the telecom industry) and he
 # can say for certain that Atikokan has been practicing the current
 # time keeping since 1952, at least.
 # From Paul Eggert (2006-07-17):
 # Shanks & Pottenger say that Atikokan has agreed with Rainy River
 # ever since standard time was introduced, but the information from
 # McKinnon sounds more authoritative.  For now, assume that Atikokan
 # switched to EST immediately after WWII era daylight saving time
 # ended.  This matches the old (less-populous) America/Coral_Harbour
 # entry since our cutoff date of 1970, so we can move
 # America/Coral_Harbour to the 'backward' file.
 # From Mark Brader (2010-03-06):
 #
 # Currently the database has:
@ -1842,11 +1781,7 @@ Zone America/Rainy_River -6:18:16 -	LMT	1895
 			-6:00	Canada	C%sT	1940 Sep 29
 			-6:00	1:00	CDT	1942 Feb  9  2:00s
 			-6:00	Canada	C%sT
-Zone America/Atikokan	-6:06:28 -	LMT	1895
+# For Atikokan see America/Panama.
 			-6:00	Canada	C%sT	1940 Sep 29
 			-6:00	1:00	CDT	1942 Feb  9  2:00s
 			-6:00	Canada	C%sT	1945 Sep 30  2:00
 			-5:00	-	EST
 # Manitoba
@ -2037,60 +1972,6 @@ Zone America/Edmonton	-7:33:52 -	LMT	1906 Sep
 # Shanks & Pottenger write that since 1970 most of this region has
 # been like Vancouver.
 # Dawson Creek uses MST.  Much of east BC is like Edmonton.
 # Matthews and Vincent (1998) write that Creston is like Dawson Creek.
 # It seems though that (re: Creston) is not entirely correct:
 # From Chris Walton (2011-12-01):
 # There are two areas within the Canadian province of British Columbia
 # that do not currently observe daylight saving:
 # a) The Creston Valley (includes the town of Creston and surrounding area)
 # b) The eastern half of the Peace River Regional District
 # (includes the cities of Dawson Creek and Fort St. John)
 # Earlier this year I stumbled across a detailed article about the time
 # keeping history of Creston; it was written by Tammy Hardwick who is the
 # manager of the Creston & District Museum. The article was written in May 2009.
 # http://www.ilovecreston.com/?p=articles&t=spec&ar=260
 # According to the article, Creston has not changed its clocks since June 1918.
 # i.e. Creston has been stuck on UT-7 for 93 years.
 # Dawson Creek, on the other hand, changed its clocks as recently as April 1972.
 # Unfortunately the exact date for the time change in June 1918 remains
 # unknown and will be difficult to ascertain.  I e-mailed Tammy a few months
 # ago to ask if Sunday June 2 was a reasonable guess.  She said it was just
 # as plausible as any other date (in June).  She also said that after writing
 # the article she had discovered another time change in 1916; this is the
 # subject of another article which she wrote in October 2010.
 # http://www.creston.museum.bc.ca/index.php?module=comments&uop=view_comment&cm+id=56
 # Here is a summary of the three clock change events in Creston's history:
 # 1. 1884 or 1885: adoption of Mountain Standard Time (GMT-7)
 # Exact date unknown
 # 2. Oct 1916: switch to Pacific Standard Time (GMT-8)
 # Exact date in October unknown; Sunday October 1 is a reasonable guess.
 # 3. June 1918: switch to Pacific Daylight Time (GMT-7)
 # Exact date in June unknown; Sunday June 2 is a reasonable guess.
 # note 1:
 # On Oct 27/1918 when daylight saving ended in the rest of Canada,
 # Creston did not change its clocks.
 # note 2:
 # During WWII when the Federal Government legislated a mandatory clock change,
 # Creston did not oblige.
 # note 3:
 # There is no guarantee that Creston will remain on Mountain Standard Time
 # (UTC-7) forever.
 # The subject was debated at least once this year by the town Council.
 # http://www.bclocalnews.com/kootenay_rockies/crestonvalleyadvance/news/116760809.html
 # During a period WWII, summer time (Daylight saying) was mandatory in Canada.
 # In Creston, that was handled by shifting the area to PST (-8:00) then applying
 # summer time to cause the offset to be -7:00, the same as it had been before
 # the change.  It can be argued that the timezone abbreviation during this
 # period should be PDT rather than MST, but that doesn't seem important enough
 # (to anyone) to further complicate the rules.
 # The transition dates (and times) are guesses.
 # From Matt Johnson (2015-09-21):
 # Fort Nelson, BC, Canada will cancel DST this year.  So while previously they
@ -2144,10 +2025,7 @@ Zone America/Fort_Nelson	-8:10:47 -	LMT	1884
 			-8:00	Vanc	P%sT	1987
 			-8:00	Canada	P%sT	2015 Mar  8  2:00
 			-7:00	-	MST
-Zone America/Creston	-7:46:04 -	LMT	1884
+# For Creston see America/Phoenix.
 			-7:00	-	MST	1916 Oct 1
 			-8:00	-	PST	1918 Jun 2
 			-7:00	-	MST
 # Northwest Territories, Nunavut, Yukon
@ -2929,64 +2807,61 @@ Zone America/Tijuana	-7:48:04 -	LMT	1922 Jan  1  0:11:56
 # Anguilla
 # Antigua and Barbuda
-# See America/Port_of_Spain.
+# See America/Puerto_Rico.
-# Bahamas
+# The Bahamas
-#
+# See America/Montreal.
 # For 1899 Milne gives -5:09:29.5; round that.
 #
 # From P Chan (2020-11-27, corrected on 2020-12-02):
 # There were two periods of DST observed in 1942-1945: 1942-05-01
 # midnight to 1944-12-31 midnight and 1945-02-01 to 1945-10-17 midnight.
 # "midnight" should mean 24:00 from the context.
 #
 # War Time Order 1942 [1942-05-01] and War Time (No. 2) Order 1942  [1942-09-29]
 # Appendix to the Statutes of 7 George VI. and the Year 1942. p 34, 43
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA3-PA34
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA3-PA43
 #
 # War Time Order 1943 [1943-03-31] and War Time Order 1944 [1943-12-29]
 # Appendix to the Statutes of 8 George VI. and the Year 1943. p 9-10, 28-29
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA4-PA9
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA4-PA28
 #
 # War Time Order 1945 [1945-01-31] and the Order which revoke War Time Order
 # 1945 [1945-10-16] Appendix to the Statutes of 9 George VI. and the Year
 # 1945. p 160, 247-248
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA6-PA160
 # https://books.google.com/books?id=5rlNAQAAIAAJ&pg=RA6-PA247
 #
 # From Sue Williams (2006-12-07):
 # The Bahamas announced about a month ago that they plan to change their DST
 # rules to sync with the U.S. starting in 2007....
 # http://www.jonesbahamas.com/?c=45&a=10412
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Bahamas	1942	only	-	May	 1	24:00	1:00	W
 Rule	Bahamas	1944	only	-	Dec	31	24:00	0	S
 Rule	Bahamas	1945	only	-	Feb	 1	0:00	1:00	W
 Rule	Bahamas	1945	only	-	Aug	14	23:00u	1:00	P # Peace
 Rule	Bahamas	1945	only	-	Oct	17	24:00	0	S
 Rule	Bahamas	1964	1975	-	Oct	lastSun	2:00	0	S
 Rule	Bahamas	1964	1975	-	Apr	lastSun	2:00	1:00	D
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Nassau	-5:09:30 -	LMT	1912 Mar 2
 			-5:00	Bahamas	E%sT	1976
 			-5:00	US	E%sT
 # Barbados
 # For 1899 Milne gives -3:58:29.2; round that.
 # From P Chan (2020-12-09 and 2020-12-11):
 # Standard time of GMT-4 was adopted in 1911.
 # Definition of Time Act, 1911 (1911-7) [1911-08-28]
 # 1912, Laws of Barbados (5 v.), OCLC Number: 919801291, Vol. 4, Image No. 522
 # 1944, Laws of Barbados (5 v.), OCLC Number: 84548697, Vol. 4, Image No. 122
 # http://llmc.com/browse.aspx?type=2&coll=85&div=297
 #
 # DST was observed in 1942-44.
 # Defence (Daylight Saving) Regulations, 1942, 1942-04-13
 # Defence (Daylight Saving) (Repeal) Regulations, 1942, 1942-08-22
 # Defence (Daylight Saving) Regulations, 1943, 1943-04-16
 # Defence (Daylight Saving) (Repeal) Regulations, 1943, 1943-09-01
 # Defence (Daylight Saving) Regulations, 1944, 1944-03-21
 # [Defence (Daylight Saving) (Amendment) Regulations 1944, 1944-03-28]
 # Defence (Daylight Saving) (Repeal) Regulations, 1944, 1944-08-30
 #
 # 1914-, Subsidiary Legis., Annual Vols. OCLC Number: 226290591
 # 1942: Image Nos. 527-528, 555-556
 # 1943: Image Nos. 178-179, 198
 # 1944: Image Nos. 113-115, 129
 # http://llmc.com/titledescfull.aspx?type=2&coll=85&div=297&set=98437
 #
 # From Tim Parenti (2021-02-20):
 # The transitions below are derived from P Chan's sources, except that the 1977
 # through 1980 transitions are from Shanks & Pottenger since we have no better
 # data there.  Of particular note, the 1944 DST regulation only advanced the
 # time to "exactly three and a half hours later than Greenwich mean time", as
 # opposed to "three hours" in the 1942 and 1943 regulations.
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Barb	1942	only	-	Apr	19	5:00u	1:00	D
 Rule	Barb	1942	only	-	Aug	31	6:00u	0	S
 Rule	Barb	1943	only	-	May	 2	5:00u	1:00	D
 Rule	Barb	1943	only	-	Sep	 5	6:00u	0	S
 Rule	Barb	1944	only	-	Apr	10	5:00u	0:30	-
 Rule	Barb	1944	only	-	Sep	10	6:00u	0	S
 Rule	Barb	1977	only	-	Jun	12	2:00	1:00	D
 Rule	Barb	1977	1978	-	Oct	Sun>=1	2:00	0	S
 Rule	Barb	1978	1980	-	Apr	Sun>=15	2:00	1:00	D
 Rule	Barb	1979	only	-	Sep	30	2:00	0	S
 Rule	Barb	1980	only	-	Sep	25	2:00	0	S
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone America/Barbados	-3:58:29 -	LMT	1924 # Bridgetown
+Zone America/Barbados	-3:58:29 -	LMT	1911 Aug 28 # Bridgetown
-			-3:58:29 -	BMT	1932 # Bridgetown Mean Time
+			-4:00	Barb	A%sT	1944
 			-4:00	Barb	AST/-0330 1945
 			-4:00	Barb	A%sT
 # Belize
@ -3148,6 +3023,9 @@ Zone Atlantic/Bermuda	-4:19:18 -	LMT	1890	# Hamilton
 			-4:00	Canada	A%sT	1976
 			-4:00	US	A%sT
 # Caribbean Netherlands
 # See America/Puerto_Rico.
 # Cayman Is
 # See America/Panama.
@ -3376,7 +3254,7 @@ Zone	America/Havana	-5:29:28 -	LMT	1890
 			-5:00	Cuba	C%sT
 # Dominica
-# See America/Port_of_Spain.
+# See America/Puerto_Rico.
 # Dominican Republic
@ -3428,7 +3306,7 @@ Zone America/El_Salvador -5:56:48 -	LMT	1921 # San Salvador
 # Guadeloupe
 # St Barthélemy
 # St Martin (French part)
-# See America/Port_of_Spain.
+# See America/Puerto_Rico.
 # Guatemala
 #
@ -3615,7 +3493,7 @@ Zone America/Martinique	-4:04:20 -      LMT	1890        # Fort-de-France
 			-4:00	-	AST
 # Montserrat
-# See America/Port_of_Spain.
+# See America/Puerto_Rico.
 # Nicaragua
 #
@ -3687,7 +3565,6 @@ Zone	America/Managua	-5:45:08 -	LMT	1890
 Zone	America/Panama	-5:18:08 -	LMT	1890
 			-5:19:36 -	CMT	1908 Apr 22 # Colón Mean Time
 			-5:00	-	EST
 Link America/Panama America/Cayman
 # Puerto Rico
 # There are too many San Juans elsewhere, so we'll use 'Puerto_Rico'.
@ -3699,7 +3576,7 @@ Zone America/Puerto_Rico -4:24:25 -	LMT	1899 Mar 28 12:00 # San Juan
 # St Kitts-Nevis
 # St Lucia
-# See America/Port_of_Spain.
+# See America/Puerto_Rico.
 # St Pierre and Miquelon
 # There are too many St Pierres elsewhere, so we'll use 'Miquelon'.
@ -3710,7 +3587,10 @@ Zone America/Miquelon	-3:44:40 -	LMT	1911 May 15 # St Pierre
 			-3:00	Canada	-03/-02
 # St Vincent and the Grenadines
-# See America/Port_of_Spain.
+# See America/Puerto_Rico.
 # Sint Maarten
 # See America/Puerto_Rico.
 # Turks and Caicos
 #
@ -3781,8 +3661,8 @@ Zone America/Grand_Turk	-4:44:32 -	LMT	1890
 			-5:00	US	E%sT
 # British Virgin Is
-# Virgin Is
+# US Virgin Is
-# See America/Port_of_Spain.
+# See America/Puerto_Rico.
 # Local Variables:
--- a/contrib/tzdata/southamerica
+++ b/contrib/tzdata/southamerica
@ -574,7 +574,7 @@ Zone America/Argentina/Ushuaia -4:33:12 - LMT	1894 Oct 31
 			-3:00	-	-03
 # Aruba
-Link America/Curacao America/Aruba
+# See America/Puerto_Rico.
 # Bolivia
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
@ -1369,35 +1369,14 @@ Zone	America/Bogota	-4:56:16 -	LMT	1884 Mar 13
 # no information; probably like America/Bogota
 # Curaçao
-
+# See America/Puerto_Rico.
 # Milne gives 4:35:46.9 for Curaçao mean time; round to nearest.
 #
 # From Paul Eggert (2006-03-22):
 # Shanks & Pottenger say that The Bottom and Philipsburg have been at
 # -4:00 since standard time was introduced on 1912-03-02; and that
 # Kralendijk and Rincon used Kralendijk Mean Time (-4:33:08) from
 # 1912-02-02 to 1965-01-01.  The former is dubious, since S&P also say
 # Saba Island has been like Curaçao.
 # This all predates our 1970 cutoff, though.
 #
 # By July 2007 Curaçao and St Maarten are planned to become
 # associated states within the Netherlands, much like Aruba;
 # Bonaire, Saba and St Eustatius would become directly part of the
 # Netherlands as Kingdom Islands.  This won't affect their time zones
 # though, as far as we know.
 #
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Curacao	-4:35:47 -	LMT	1912 Feb 12 # Willemstad
 			-4:30	-	-0430	1965
 			-4:00	-	AST
 # From Arthur David Olson (2011-06-15):
 # use links for places with new iso3166 codes.
 # The name "Lower Prince's Quarter" is both longer than fourteen characters
-# and contains an apostrophe; use "Lower_Princes" below.
+# and contains an apostrophe; use "Lower_Princes"....
-
+# From Paul Eggert (2021-05-06):
-Link	America/Curacao	America/Lower_Princes	# Sint Maarten
+# These backward-compatibility links now are in the 'backward' file.
 Link	America/Curacao	America/Kralendijk	# Caribbean Netherlands
 # Ecuador
 #
@ -1540,11 +1519,40 @@ Zone America/Cayenne	-3:29:20 -	LMT	1911 Jul
 			-3:00	-	-03
 # Guyana
 # From P Chan (2020-11-27):
 # https://books.google.com/books?id=5-5CAQAAMAAJ&pg=SA1-PA547
 # The Official Gazette of British Guiana. (New Series.) Vol. XL. July to
 # December, 1915, p 1547, lists as several notes:
 # "Local Mean Time 3 hours 52 mins. 39 secs. slow of Greenwich Mean Time
 # (Georgetown.) From 1st August, 1911, British Guiana Standard Mean Time 4
 # hours slow of Greenwich Mean Time, by notice in Official Gazette on 1st July,
 # 1911.  From 1st March, 1915, British Guiana Standard Mean Time 3 hours 45
 # mins. 0 secs. slow of Greenwich Mean Time, by notice in Official Gazette on
 # 23rd January, 1915."
 #
 # https://parliament.gov.gy/documents/acts/10923-act_no._27_of_1975_-_interpretation_and_general_clauses_(amendment)_act_1975.pdf
 # Interpretation and general clauses (Amendment) Act 1975 (Act No. 27 of 1975)
 # [dated 1975-07-31]
 # "This Act...shall come into operation on 1st August, 1975."
 # "...where any expression of time occurs...the time referred to shall signify
 # the standard time of Guyana which shall be three hours behind Greenwich Mean
 # Time."
 #
 # Circular No. 10/1992 dated 1992-03-20
 # https://dps.gov.gy/wp-content/uploads/2018/12/1992-03-20-Circular-010.pdf
 # "...cabinet has decided that with effect from Sunday 29th March, 1992, Guyana
 # Standard Time would be re-established at 01:00 hours by adjusting the hands
 # of the clock back to 24:00 hours."
 # Legislated in the Interpretation and general clauses (Amendment) Act 1992
 # (Act No. 6 of 1992) [passed 1992-03-27, published 1992-04-18]
 # https://parliament.gov.gy/documents/acts/5885-6_of_1992_interpretation_and_general_clauses_(amendment)_act_1992.pdf
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	America/Guyana	-3:52:40 -	LMT	1915 Mar    # Georgetown
+Zone	America/Guyana	-3:52:39 -	LMT	1911 Aug  1 # Georgetown
-			-3:45	-	-0345	1975 Jul 31
+			-4:00	-	-04	1915 Mar  1
-			-3:00	-	-03	1991
+			-3:45	-	-0345	1975 Aug  1
-# IATA SSIM (1996-06) says -4:00.  Assume a 1991 switch.
+			-3:00	-	-03	1992 Mar 29  1:00
 			-4:00	-	-04
 # Paraguay
@ -1685,24 +1693,7 @@ Zone America/Paramaribo	-3:40:40 -	LMT	1911
 			-3:00	-	-03
 # Trinidad and Tobago
-# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
+# See America/Puerto_Rico.
 Zone America/Port_of_Spain -4:06:04 -	LMT	1912 Mar 2
 			-4:00	-	AST
 # These all agree with Trinidad and Tobago since 1970.
 Link America/Port_of_Spain America/Anguilla
 Link America/Port_of_Spain America/Antigua
 Link America/Port_of_Spain America/Dominica
 Link America/Port_of_Spain America/Grenada
 Link America/Port_of_Spain America/Guadeloupe
 Link America/Port_of_Spain America/Marigot	# St Martin (French part)
 Link America/Port_of_Spain America/Montserrat
 Link America/Port_of_Spain America/St_Barthelemy # St Barthélemy
 Link America/Port_of_Spain America/St_Kitts	# St Kitts & Nevis
 Link America/Port_of_Spain America/St_Lucia
 Link America/Port_of_Spain America/St_Thomas	# Virgin Islands (US)
 Link America/Port_of_Spain America/St_Vincent
 Link America/Port_of_Spain America/Tortola	# Virgin Islands (UK)
 # Uruguay
 # From Paul Eggert (1993-11-18):
--- a/contrib/tzdata/theory.html
+++ b/contrib/tzdata/theory.html
@ -42,12 +42,13 @@ href="https://en.wikipedia.org/wiki/Unix_time">POSIX Epoch</a>
 (1970-01-01 00:00:00 <a
 href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time"><abbr
 title="Coordinated Universal Time">UTC</abbr></a>).
 The database labels each timezone with a notable location and
 records all known clock transitions for that location.
 Although 1970 is a somewhat-arbitrary cutoff, there are significant
 challenges to moving the cutoff earlier even by a decade or two, due
 to the wide variety of local practices before computer timekeeping
 became prevalent.
 Most timezones correspond to a notable location and the database
 records all known clock transitions for that location;
 some timezones correspond instead to a fixed <abbr>UTC</abbr> offset.
 </p>
 <p>
@ -58,8 +59,9 @@ specifies current standard time. For example, applications that deal
 with current and future timestamps in the traditional North
 American mountain time zone can choose from the timezones
 <code>America/Denver</code> which observes US-style daylight saving
-time, <code>America/Mazatlan</code> which observes Mexican-style DST,
+time (<abbr>DST</abbr>),
-and <code>America/Phoenix</code> which does not observe DST.
+<code>America/Mazatlan</code> which observes Mexican-style <abbr>DST</abbr>,
 and <code>America/Phoenix</code> which does not observe <abbr>DST</abbr>.
 Applications that also deal with past timestamps in the mountain time
 zone can choose from over a dozen timezones, such as
 <code>America/Boise</code>, <code>America/Edmonton</code>, and
@ -68,7 +70,7 @@ time but differs from other timezones for some timestamps after 1970.
 </p>
 <p>
-Clock transitions before 1970 are recorded for each timezone,
+Clock transitions before 1970 are recorded for location-based timezones,
 because most systems support timestamps before 1970 and could
 misbehave if data entries were omitted for pre-1970 transitions.
 However, the database is not designed for and does not suffice for
@ -190,8 +192,8 @@ in decreasing order of importance:
    <code>TZ</code> strings</a>.
    A file name component must not exceed 14 characters or start with
    '<code>-</code>'.
-    E.g., prefer <code>Asia/Brunei</code> to
+    E.g., prefer <code>America/Noronha</code> to
-    <code>Asia/Bandar_Seri_Begawan</code>.
+    <code>America/Fernando_de_Noronha</code>.
    Exceptions: see the discussion of legacy names below.
  </li>
  <li>
@ -473,10 +475,10 @@ in decreasing order of importance:
    <p>
    <small>These abbreviations are:
-      AMT Amsterdam, Asunción, Athens;
+      AMT Asunción, Athens;
      BMT Baghdad, Bangkok, Batavia, Bermuda, Bern, Bogotá, Bridgetown,
        Brussels, Bucharest;
-      CMT Calamarca, Caracas, Chisinau, Colón, Copenhagen, Córdoba;
+      CMT Calamarca, Caracas, Chisinau, Colón, Córdoba;
      DMT Dublin/Dunsink;
      EMT Easter;
      FFMT Fort-de-France;
@ -499,7 +501,8 @@ in decreasing order of importance:
      SMT Santiago, Simferopol, Singapore, Stanley;
      TBMT Tbilisi;
      TMT Tallinn, Tehran;
-      WMT Warsaw</small>.
+      WMT Warsaw;
      ZMT Zomba.</small>
    </p>
    <p>
@ -513,9 +516,7 @@ in decreasing order of importance:
 	1880&ndash;1916,
      MMT/MST/MDST for Moscow 1880&ndash;1919, and
      RMT/LST for Riga Mean Time and Latvian Summer time 1880&ndash;1926.
-    An extra-special case is SET for Swedish Time (<em>svensk
+    </small>
    normaltid</em>) 1879&ndash;1899, 3&deg; west of the Stockholm
    Observatory.</small>
    </p>
  </li>
  <li>
@ -702,11 +703,9 @@ href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanes
  <li>
    Sometimes historical timekeeping was specified more precisely
    than what the <code><abbr>tz</abbr></code> code can handle.
-    For example, from 1909 to 1937 <a
+    For example, from 1880 to 1916 clocks in Ireland observed Dublin Mean
    href="https://www.staff.science.uu.nl/~gent0113/wettijd/wettijd.htm"
    hreflang="nl">Netherlands clocks</a> were legally Amsterdam Mean
    Time (estimated to be <abbr>UT</abbr>
-    +00:19:32.13), but the <code><abbr>tz</abbr></code>
+    &minus;00:25:21.1), but the <code><abbr>tz</abbr></code>
    code cannot represent the fractional second.
    In practice these old specifications were rarely if ever
    implemented to subsecond precision.
@ -753,7 +752,8 @@ href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanes
    the Western 06:00 to be 12:00. These practices are largely outside
    the scope of the <code><abbr>tz</abbr></code> code and data, which
    provide only limited support for date and time localization
-    such as that required by POSIX. If DST is not used a different time zone
+    such as that required by POSIX.
    If <abbr>DST</abbr> is not used a different time zone
    can often do the trick; for example, in Kenya a <code>TZ</code> setting
    like <code>&lt;-03&gt;3</code> or <code>America/Cayenne</code> starts
    the day six hours later than <code>Africa/Nairobi</code> does.
@ -1271,7 +1271,8 @@ The directly-supported mechanism assumes that <code>time_t</code>
 counts of seconds since the POSIX epoch normally include leap seconds,
 as opposed to POSIX <code>time_t</code> counts which exclude leap seconds.
 This modified timescale is converted to <abbr>UTC</abbr>
-at the same point that time zone and DST adjustments are applied &ndash;
+at the same point that time zone and <abbr>DST</abbr>
 adjustments are applied &ndash;
 namely, at calls to <code>localtime</code> and analogous functions &ndash;
 and the process is driven by leap second information
 stored in alternate versions of the <abbr>TZif</abbr> files.
--- a/contrib/tzdata/version
+++ b/contrib/tzdata/version
@ -1 +1 @@
-2021a
+2021b
--- a/contrib/tzdata/ziguard.awk
+++ b/contrib/tzdata/ziguard.awk
@ -114,15 +114,16 @@ DATAFORM != "main" {
  }
 }
-# If a Link line is followed by a Zone line for the same data, comment
+# If a Link line is followed by a Link or Zone line for the same data, comment
 # out the Link line.  This can happen if backzone overrides a Link
-# with a Zone.
+# with a Zone or a different Link.
 /^Link/ {
  linkline[$3] = NR
 }
 /^Zone/ {
  sub(/^Link/, "#Link", line[linkline[$2]])
 }
 /^Link/ {
  sub(/^Link/, "#Link", line[linkline[$3]])
  linkline[$3] = NR
 }
 { line[NR] = $0 }
--- a/contrib/tzdata/zone.tab
+++ b/contrib/tzdata/zone.tab
@ -3,7 +3,7 @@
 # This file is in the public domain, so clarified as of
 # 2009-05-17 by Arthur David Olson.
 #
-# From Paul Eggert (2018-06-27):
+# From Paul Eggert (2021-09-20):
 # This file is intended as a backward-compatibility aid for older programs.
 # New programs should use zone1970.tab.  This file is like zone1970.tab (see
 # zone1970.tab's comments), but with the following additional restrictions:
@ -16,6 +16,9 @@
 # clocks have agreed since 1970; this is a narrower definition than
 # that of zone1970.tab.
 #
 # Unlike zone1970.tab, a row's third column can be a Link from
 # 'backward' instead of a Zone.
 #
 # This table is intended as an aid for users, to help them select timezones
 # appropriate for their practical needs.  It is not intended to take or
 # endorse any position on legal or territorial claims.
@ -228,7 +231,7 @@ KE	-0117+03649	Africa/Nairobi
 KG	+4254+07436	Asia/Bishkek
 KH	+1133+10455	Asia/Phnom_Penh
 KI	+0125+17300	Pacific/Tarawa	Gilbert Islands
-KI	-0308-17105	Pacific/Enderbury	Phoenix Islands
+KI	-0247-17143	Pacific/Kanton	Phoenix Islands
 KI	+0152-15720	Pacific/Kiritimati	Line Islands
 KM	-1141+04316	Indian/Comoro
 KN	+1718-06243	America/St_Kitts
@ -391,7 +394,7 @@ TK	-0922-17114	Pacific/Fakaofo
 TL	-0833+12535	Asia/Dili
 TM	+3757+05823	Asia/Ashgabat
 TN	+3648+01011	Africa/Tunis
-TO	-2110-17510	Pacific/Tongatapu
+TO	-210800-1751200	Pacific/Tongatapu
 TR	+4101+02858	Europe/Istanbul
 TT	+1039-06131	America/Port_of_Spain
 TV	-0831+17913	Pacific/Funafuti
--- a/contrib/tzdata/zone1970.tab
+++ b/contrib/tzdata/zone1970.tab
@ -41,11 +41,9 @@ AL	+4120+01950	Europe/Tirane
 AM	+4011+04430	Asia/Yerevan
 AQ	-6617+11031	Antarctica/Casey	Casey
 AQ	-6835+07758	Antarctica/Davis	Davis
 AQ	-6640+14001	Antarctica/DumontDUrville	Dumont-d'Urville
 AQ	-6736+06253	Antarctica/Mawson	Mawson
 AQ	-6448-06406	Antarctica/Palmer	Palmer
 AQ	-6734-06808	Antarctica/Rothera	Rothera
 AQ	-690022+0393524	Antarctica/Syowa	Syowa
 AQ	-720041+0023206	Antarctica/Troll	Troll
 AQ	-7824+10654	Antarctica/Vostok	Vostok
 AR	-3436-05827	America/Argentina/Buenos_Aires	Buenos Aires (BA, CF)
@ -98,7 +96,6 @@ BR	+0249-06040	America/Boa_Vista	Roraima
 BR	-0308-06001	America/Manaus	Amazonas (east)
 BR	-0640-06952	America/Eirunepe	Amazonas (west)
 BR	-0958-06748	America/Rio_Branco	Acre
 BS	+2505-07721	America/Nassau
 BT	+2728+08939	Asia/Thimphu
 BY	+5354+02734	Europe/Minsk
 BZ	+1730-08812	America/Belize
@ -107,13 +104,11 @@ CA	+4439-06336	America/Halifax	Atlantic - NS (most areas); PE
 CA	+4612-05957	America/Glace_Bay	Atlantic - NS (Cape Breton)
 CA	+4606-06447	America/Moncton	Atlantic - New Brunswick
 CA	+5320-06025	America/Goose_Bay	Atlantic - Labrador (most areas)
-CA	+5125-05707	America/Blanc-Sablon	AST - QC (Lower North Shore)
+CA,BS	+4339-07923	America/Toronto	Eastern - ON, QC (most areas), Bahamas
 CA	+4339-07923	America/Toronto	Eastern - ON, QC (most areas)
 CA	+4901-08816	America/Nipigon	Eastern - ON, QC (no DST 1967-73)
 CA	+4823-08915	America/Thunder_Bay	Eastern - ON (Thunder Bay)
 CA	+6344-06828	America/Iqaluit	Eastern - NU (most east areas)
 CA	+6608-06544	America/Pangnirtung	Eastern - NU (Pangnirtung)
 CA	+484531-0913718	America/Atikokan	EST - ON (Atikokan); NU (Coral H)
 CA	+4953-09709	America/Winnipeg	Central - ON (west); Manitoba
 CA	+4843-09434	America/Rainy_River	Central - ON (Rainy R, Ft Frances)
 CA	+744144-0944945	America/Resolute	Central - NU (Resolute)
@ -124,7 +119,6 @@ CA	+5333-11328	America/Edmonton	Mountain - AB; BC (E); SK (W)
 CA	+690650-1050310	America/Cambridge_Bay	Mountain - NU (west)
 CA	+6227-11421	America/Yellowknife	Mountain - NT (central)
 CA	+682059-1334300	America/Inuvik	Mountain - NT (west)
 CA	+4906-11631	America/Creston	MST - BC (Creston)
 CA	+5946-12014	America/Dawson_Creek	MST - BC (Dawson Cr, Ft St John)
 CA	+5848-12242	America/Fort_Nelson	MST - BC (Ft Nelson)
 CA	+6043-13503	America/Whitehorse	MST - Yukon (east)
@ -132,7 +126,7 @@ CA	+6404-13925	America/Dawson	MST - Yukon (west)
 CA	+4916-12307	America/Vancouver	Pacific - BC (most areas)
 CC	-1210+09655	Indian/Cocos
 CH,DE,LI	+4723+00832	Europe/Zurich	Swiss time
-CI,BF,GM,GN,ML,MR,SH,SL,SN,TG	+0519-00402	Africa/Abidjan
+CI,BF,GH,GM,GN,ML,MR,SH,SL,SN,TG	+0519-00402	Africa/Abidjan
 CK	-2114-15946	Pacific/Rarotonga
 CL	-3327-07040	America/Santiago	Chile (most areas)
 CL	-5309-07055	America/Punta_Arenas	Region of Magallanes
@ -143,7 +137,6 @@ CO	+0436-07405	America/Bogota
 CR	+0956-08405	America/Costa_Rica
 CU	+2308-08222	America/Havana
 CV	+1455-02331	Atlantic/Cape_Verde
 CW,AW,BQ,SX	+1211-06900	America/Curacao
 CX	-1025+10543	Indian/Christmas
 CY	+3510+03322	Asia/Nicosia	Cyprus (most areas)
 CY	+3507+03357	Asia/Famagusta	Northern Cyprus
@ -171,7 +164,6 @@ FR	+4852+00220	Europe/Paris
 GB,GG,IM,JE	+513030-0000731	Europe/London
 GE	+4143+04449	Asia/Tbilisi
 GF	+0456-05220	America/Cayenne
 GH	+0533-00013	Africa/Accra
 GI	+3608-00521	Europe/Gibraltar
 GL	+6411-05144	America/Nuuk	Greenland (most areas)
 GL	+7646-01840	America/Danmarkshavn	National Park (east coast)
@ -205,7 +197,7 @@ JP	+353916+1394441	Asia/Tokyo
 KE,DJ,ER,ET,KM,MG,SO,TZ,UG,YT	-0117+03649	Africa/Nairobi
 KG	+4254+07436	Asia/Bishkek
 KI	+0125+17300	Pacific/Tarawa	Gilbert Islands
-KI	-0308-17105	Pacific/Enderbury	Phoenix Islands
+KI	-0247-17143	Pacific/Kanton	Phoenix Islands
 KI	+0152-15720	Pacific/Kiritimati	Line Islands
 KP	+3901+12545	Asia/Pyongyang
 KR	+3733+12658	Asia/Seoul
@ -263,19 +255,19 @@ NR	-0031+16655	Pacific/Nauru
 NU	-1901-16955	Pacific/Niue
 NZ,AQ	-3652+17446	Pacific/Auckland	New Zealand time
 NZ	-4357-17633	Pacific/Chatham	Chatham Islands
-PA,KY	+0858-07932	America/Panama
+PA,CA,KY	+0858-07932	America/Panama	EST - Panama, Cayman, ON (Atikokan), NU (Coral H)
 PE	-1203-07703	America/Lima
 PF	-1732-14934	Pacific/Tahiti	Society Islands
 PF	-0900-13930	Pacific/Marquesas	Marquesas Islands
 PF	-2308-13457	Pacific/Gambier	Gambier Islands
-PG	-0930+14710	Pacific/Port_Moresby	Papua New Guinea (most areas)
+PG,AQ	-0930+14710	Pacific/Port_Moresby	Papua New Guinea (most areas), Dumont d'Urville
 PG	-0613+15534	Pacific/Bougainville	Bougainville
 PH	+1435+12100	Asia/Manila
 PK	+2452+06703	Asia/Karachi
 PL	+5215+02100	Europe/Warsaw
 PM	+4703-05620	America/Miquelon
 PN	-2504-13005	Pacific/Pitcairn
-PR	+182806-0660622	America/Puerto_Rico
+PR,AG,CA,AI,AW,BL,BQ,CW,DM,GD,GP,KN,LC,MF,MS,SX,TT,VC,VG,VI	+182806-0660622	America/Puerto_Rico	AST
 PS	+3130+03428	Asia/Gaza	Gaza Strip
 PS	+313200+0350542	Asia/Hebron	West Bank
 PT	+3843-00908	Europe/Lisbon	Portugal (mainland)
@ -315,12 +307,12 @@ RU	+4658+14242	Asia/Sakhalin	MSK+08 - Sakhalin Island
 RU	+6728+15343	Asia/Srednekolymsk	MSK+08 - Sakha (E); North Kuril Is
 RU	+5301+15839	Asia/Kamchatka	MSK+09 - Kamchatka
 RU	+6445+17729	Asia/Anadyr	MSK+09 - Bering Sea
-SA,KW,YE	+2438+04643	Asia/Riyadh
+SA,AQ,KW,YE	+2438+04643	Asia/Riyadh	Arabia, Syowa
 SB	-0932+16012	Pacific/Guadalcanal
 SC	-0440+05528	Indian/Mahe
 SD	+1536+03232	Africa/Khartoum
 SE	+5920+01803	Europe/Stockholm
-SG	+0117+10351	Asia/Singapore
+SG,MY	+0117+10351	Asia/Singapore	Singapore, peninsular Malaysia
 SR	+0550-05510	America/Paramaribo
 SS	+0451+03137	Africa/Juba
 ST	+0020+00644	Africa/Sao_Tome
@ -335,9 +327,8 @@ TK	-0922-17114	Pacific/Fakaofo
 TL	-0833+12535	Asia/Dili
 TM	+3757+05823	Asia/Ashgabat
 TN	+3648+01011	Africa/Tunis
-TO	-2110-17510	Pacific/Tongatapu
+TO	-210800-1751200	Pacific/Tongatapu
 TR	+4101+02858	Europe/Istanbul
 TT,AG,AI,BL,DM,GD,GP,KN,LC,MF,MS,VC,VG,VI	+1039-06131	America/Port_of_Spain
 TV	-0831+17913	Pacific/Funafuti
 TW	+2503+12130	Asia/Taipei
 UA	+5026+03031	Europe/Kiev	Ukraine (most areas)
@ -363,7 +354,7 @@ US	+465042-1012439	America/North_Dakota/New_Salem	Central - ND (Morton rural)
 US	+471551-1014640	America/North_Dakota/Beulah	Central - ND (Mercer)
 US	+394421-1045903	America/Denver	Mountain (most areas)
 US	+433649-1161209	America/Boise	Mountain - ID (south); OR (east)
-US	+332654-1120424	America/Phoenix	MST - Arizona (except Navajo)
+US,CA	+332654-1120424	America/Phoenix	MST - Arizona (except Navajo), Creston BC
 US	+340308-1181434	America/Los_Angeles	Pacific
 US	+611305-1495401	America/Anchorage	Alaska (most areas)
 US	+581807-1342511	America/Juneau	Alaska - Juneau area