Update to tzdata2021e from www.iana.org. Major changes:

 o Palestine will fall back 10-29 (not 10-30) at 01:00.
 o Fiji suspends DST for the 2021/2022 season.
 o Move some backward-compatibility links to 'backward'.
 o Rename Pacific/Enderbury to Pacific/Kanton.

11 files changed, 347 insertions, 442 deletions

diff --git a/share/zoneinfo/datfiles/africa b/share/zoneinfo/datfiles/africa
index e7f1cfe1b70..469b3ac94df 100644
--- a/share/zoneinfo/datfiles/africa
+++ b/share/zoneinfo/datfiles/africa
@@ -1,4 +1,4 @@
-# $OpenBSD: africa,v 1.65 2021/01/24 20:18:50 millert Exp $
+# $OpenBSD: africa,v 1.66 2021/10/22 14:40:49 millert Exp $
 # tzdb data for Africa and environs
 
 # This file is in the public domain, so clarified as of
@@ -31,9 +31,6 @@
 # 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
@@ -154,8 +151,9 @@ 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/Accra	# Ghana
 Link Africa/Abidjan Africa/Bamako	# Mali
-Link Africa/Abidjan Africa/Banjul	# Gambia
+Link Africa/Abidjan Africa/Banjul	# The Gambia
 Link Africa/Abidjan Africa/Conakry	# Guinea
 Link Africa/Abidjan Africa/Dakar	# Senegal
 Link Africa/Abidjan Africa/Freetown	# Sierra Leone
@@ -382,93 +380,8 @@ Zone	Africa/Cairo	2:05:09 -	LMT	1900 Oct
 # Gabon
 # See Africa/Lagos.
 
-# Gambia
-# See Africa/Abidjan.
-
+# The Gambia
 # 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.
 
@@ -733,7 +646,7 @@ 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
@@ -1383,23 +1296,21 @@ 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
+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,
@@ -1491,8 +1402,8 @@ 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
+Link Africa/Johannesburg Africa/Maseru	# Lesotho
+Link Africa/Johannesburg Africa/Mbabane	# Eswatini
 #
 # Marion and Prince Edward Is
 # scientific station since 1947
@@ -1528,12 +1439,13 @@ 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
@@ -1638,7 +1550,7 @@ 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
diff --git a/share/zoneinfo/datfiles/antarctica b/share/zoneinfo/datfiles/antarctica
index 80f49897213..c6b5f7002d5 100644
--- a/share/zoneinfo/datfiles/antarctica
+++ b/share/zoneinfo/datfiles/antarctica
@@ -1,4 +1,4 @@
-# $OpenBSD: antarctica,v 1.42 2020/10/07 22:33:31 millert Exp $
+# $OpenBSD: antarctica,v 1.43 2021/10/22 14:40:49 millert Exp $
 # tzdb data for Antarctica and environs
 
 # This file is in the public domain, so clarified as of
@@ -149,7 +149,7 @@ 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;
@@ -163,17 +163,7 @@ 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
-# <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
+# Dumont d'Urville - see Pacific/Port_Moresby.
 
 # France & Italy - year-round base
 # Concordia, -750600+1232000, since 2005
@@ -189,20 +179,7 @@ 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
-#
-# 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
+# See Asia/Riyadh.
 
 # S Korea - year-round base
 # Jang Bogo, Terra Nova Bay, -743700+1641205 since 2014
diff --git a/share/zoneinfo/datfiles/asia b/share/zoneinfo/datfiles/asia
index d40eb214039..626fc9bee04 100644
--- a/share/zoneinfo/datfiles/asia
+++ b/share/zoneinfo/datfiles/asia
@@ -1,4 +1,4 @@
-# $OpenBSD: asia,v 1.95 2021/09/24 15:02:07 millert Exp $
+# $OpenBSD: asia,v 1.96 2021/10/22 14:40:49 millert Exp $
 # tzdb data for Asia and environs
 
 # This file is in the public domain, so clarified as of
@@ -35,9 +35,6 @@
 # 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
@@ -2750,7 +2747,8 @@ 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.
@@ -3389,11 +3387,6 @@ Zone	Asia/Karachi	4:28:12 -	LMT	1907
 # shall [end] on Oct 24th 2020 at 01:00AM by delaying the clock by 60 minutes.
 # http://www.palestinecabinet.gov.ps/portal/Meeting/Details/51584
 
-# From Tim Parenti (2020-10-20):
-# Predict future fall transitions at 01:00 on the Saturday preceding October's
-# last Sunday (i.e., Sat>=24).  This is consistent with our predictions since
-# 2016, although the time of the change differed slightly in 2019.
-
 # From Pierre Cashon (2020-10-20):
 # The summer time this year started on March 28 at 00:00.
 # https://wafa.ps/ar_page.aspx?id=GveQNZa872839351758aGveQNZ
@@ -3406,6 +3399,17 @@ Zone	Asia/Karachi	4:28:12 -	LMT	1907
 # For now, guess spring-ahead transitions are at 00:00 on the Saturday
 # preceding March's last Sunday (i.e., Sat>=24).
 
+# From P Chan (2021-10-18):
+# http://wafa.ps/Pages/Details/34701
+# Palestine winter time will start from midnight 2021-10-29 (Thursday-Friday).
+#
+# From Heba Hemad, Palestine Ministry of Telecom & IT (2021-10-20):
+# ... winter time will begin in Palestine from Friday 10-29, 01:00 AM
+# by 60 minutes backwards.
+#
+# From Paul Eggert (2021-10-20):
+# Guess future fall transitions on October's last Friday at 01:00.
+
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule EgyptAsia	1957	only	-	May	10	0:00	1:00	S
 Rule EgyptAsia	1957	1958	-	Oct	 1	0:00	0	-
@@ -3441,7 +3445,8 @@ Rule Palestine	2016	2018	-	Oct	Sat>=24	1:00	0	-
 Rule Palestine	2019	only	-	Mar	29	0:00	1:00	S
 Rule Palestine	2019	only	-	Oct	Sat>=24	0:00	0	-
 Rule Palestine	2020	max	-	Mar	Sat>=24	0:00	1:00	S
-Rule Palestine	2020	max	-	Oct	Sat>=24	1:00	0	-
+Rule Palestine	2020	only	-	Oct	24	1:00	0	-
+Rule Palestine	2021	max	-	Oct	lastFri	1:00	0	-
 
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Gaza	2:17:52	-	LMT	1900 Oct
@@ -3510,6 +3515,12 @@ 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
@@ -3576,12 +3587,13 @@ 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 Antarctica/Syowa
 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.
diff --git a/share/zoneinfo/datfiles/australasia b/share/zoneinfo/datfiles/australasia
index 24de5a60024..aa8bacac18f 100644
--- a/share/zoneinfo/datfiles/australasia
+++ b/share/zoneinfo/datfiles/australasia
@@ -1,4 +1,4 @@
-# $OpenBSD: australasia,v 1.71 2021/09/23 21:37:34 millert Exp $
+# $OpenBSD: australasia,v 1.72 2021/10/22 14:40:49 millert Exp $
 # tzdb data for Australasia and environs, and for much of the Pacific
 
 # This file is in the public domain, so clarified as of
@@ -386,9 +386,22 @@ Zone	Indian/Cocos	6:27:40	-	LMT	1900
 # "Minister for Employment, Parveen Bala says they had never thought of
 # stopping daylight saving. He says it was just to decide on when it should
 # start and end.  Bala says it is a short period..."
-# Since the end date is still in line with our ongoing predictions, assume for
-# now that the later-than-usual start date is a one-time departure from the
-# recent second Sunday in November pattern.
+#
+# From Tim Parenti (2021-10-11), per Jashneel Kumar (2021-10-11) and P Chan
+# (2021-10-12):
+# https://www.fiji.gov.fj/Media-Centre/Speeches/English/PM-BAINIMARAMA-S-COVID-19-ANNOUNCEMENT-10-10-21
+# https://www.fbcnews.com.fj/news/covid-19/curfew-moved-back-to-11pm/
+# In a 2021-10-10 speech concerning updated Covid-19 mitigation measures in
+# Fiji, prime minister Josaia Voreqe "Frank" Bainimarama announced the
+# suspension of DST for the 2021/2022 season: "Given that we are in the process
+# of readjusting in the midst of so many changes, we will also put Daylight
+# Savings Time on hold for this year. It will also make the reopening of
+# scheduled commercial air service much smoother if we don't have to be
+# concerned shifting arrival and departure times, which may look like a simple
+# thing but requires some significant logistical adjustments domestically and
+# internationally."
+# Assume for now that DST will resume with the recent pre-2020 rules for the
+# 2022/2023 season.
 
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Fiji	1998	1999	-	Nov	Sun>=1	2:00	1:00	-
@@ -400,10 +413,11 @@ Rule	Fiji	2011	only	-	Mar	Sun>=1	3:00	0	-
 Rule	Fiji	2012	2013	-	Jan	Sun>=18	3:00	0	-
 Rule	Fiji	2014	only	-	Jan	Sun>=18	2:00	0	-
 Rule	Fiji	2014	2018	-	Nov	Sun>=1	2:00	1:00	-
-Rule	Fiji	2015	max	-	Jan	Sun>=12	3:00	0	-
+Rule	Fiji	2015	2021	-	Jan	Sun>=12	3:00	0	-
 Rule	Fiji	2019	only	-	Nov	Sun>=8	2:00	1:00	-
 Rule	Fiji	2020	only	-	Dec	20	2:00	1:00	-
-Rule	Fiji	2021	max	-	Nov	Sun>=8	2:00	1:00	-
+Rule	Fiji	2022	max	-	Nov	Sun>=8	2:00	1:00	-
+Rule	Fiji	2023	max	-	Jan	Sun>=12	3:00	0	-
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Fiji	11:55:44 -	LMT	1915 Oct 26 # Suva
 			12:00	Fiji	+12/+13
@@ -465,7 +479,7 @@ Link Pacific/Guam Pacific/Saipan # N Mariana Is
 # 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
@@ -598,13 +612,46 @@ 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
 
@@ -612,10 +659,18 @@ 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
-			-11:20	-	-1120	1951
-			-11:30	-	-1130	1978 Oct  1
+Zone	Pacific/Niue	-11:19:40 -	LMT	1952 Oct 16	# Alofi
+			-11:20	-	-1120	1964 Jul
 			-11:00	-	-11
 
 # Norfolk
@@ -639,6 +694,7 @@ Zone Pacific/Palau	-15:02:04 -	LMT	1844 Dec 31	# Koror
 Zone Pacific/Port_Moresby 9:48:40 -	LMT	1880
 			9:48:32	-	PMMT	1895 # Port Moresby Mean Time
 			10:00	-	+10
+Link Pacific/Port_Moresby Antarctica/DumontDUrville
 #
 # From Paul Eggert (2014-10-13):
 # Base the Bougainville entry on the Arawa-Kieta region, which appears to have
@@ -800,8 +856,8 @@ 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
-			12:20	-	+1220	1941
+Zone Pacific/Tongatapu	12:19:12 -	LMT	1945 Sep 10
+			12:20	-	+1220	1961
 			13:00	-	+13	1999
 			13:00	Tonga	+13/+14
 
@@ -1743,6 +1799,23 @@ 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):
@@ -2026,6 +2099,17 @@ 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."
@@ -2054,9 +2138,26 @@ 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):
-# Shanks & Pottenger say the transition was on 1968-10-01; go with Mundell.
+#
+# From Tim Parenti (2021-09-13), per Paul Eggert (2006-03-22) and Michael
+# 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
diff --git a/share/zoneinfo/datfiles/backward b/share/zoneinfo/datfiles/backward
index 2f22872a510..229653ffdda 100644
--- a/share/zoneinfo/datfiles/backward
+++ b/share/zoneinfo/datfiles/backward
@@ -1,11 +1,13 @@
-# $OpenBSD: backward,v 1.38 2020/12/23 13:06:27 millert Exp $
+# $OpenBSD: backward,v 1.39 2021/10/22 14:40:49 millert Exp $
 # tzdb links for backward compatibility
 
 # 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
-# and their old names.  Many names changed in late 1993.
+# This file provides links from old or merged timezone names to current ones.
+# Many names changed in late 1993.  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/Nairobi		Africa/Asmera
@@ -14,7 +16,7 @@ Link	America/Argentina/Catamarca	America/Argentina/ComodRivadavia
 Link	America/Adak		America/Atka
 Link	America/Argentina/Buenos_Aires	America/Buenos_Aires
 Link	America/Argentina/Catamarca	America/Catamarca
-Link	America/Atikokan	America/Coral_Harbour
+Link	America/Panama		America/Coral_Harbour
 Link	America/Argentina/Cordoba	America/Cordoba
 Link	America/Tijuana		America/Ensenada
 Link	America/Indiana/Indianapolis	America/Fort_Wayne
@@ -29,7 +31,7 @@ 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/Virgin
 Link	Pacific/Auckland	Antarctica/South_Pole
 Link	Asia/Ashgabat		Asia/Ashkhabad
 Link	Asia/Kolkata		Asia/Calcutta
@@ -104,6 +106,7 @@ 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/Pohnpei		Pacific/Ponape
 Link	Pacific/Pago_Pago	Pacific/Samoa
diff --git a/share/zoneinfo/datfiles/europe b/share/zoneinfo/datfiles/europe
index a5228640ab4..edf3fec3cdf 100644
--- a/share/zoneinfo/datfiles/europe
+++ b/share/zoneinfo/datfiles/europe
@@ -1,4 +1,4 @@
-# $OpenBSD: europe,v 1.81 2020/12/23 13:06:27 millert Exp $
+# $OpenBSD: europe,v 1.82 2021/10/22 14:40:49 millert Exp $
 # tzdb data for Europe and environs
 
 # This file is in the public domain, so clarified as of
@@ -69,7 +69,6 @@
 #        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
@@ -823,7 +822,7 @@ Zone	Europe/Andorra	0:06:04 -	LMT	1901
 # Shanks & Pottenger give 02:00, the BEV 00:00.  Go with the BEV,
 # and guess 02:00 for 1945-04-12.
 
-# From Alois Triendl (2019-07-22):
+# From Alois Treindl (2019-07-22):
 # In 1946 the end of DST was on Monday, 7 October 1946, at 3:00 am.
 # Shanks had this right.  Source: Die Weltpresse, 5. Oktober 1946, page 5.
 
@@ -1737,19 +1736,22 @@ Zone Atlantic/Reykjavik	-1:28	-	LMT	1908
 # advanced to sixty minutes later starting at hour two on 1944-04-02; ...
 # Starting at hour three on the date 1944-09-17 standard time will be resumed.
 #
-# From Alois Triendl (2019-07-02):
+# From Alois Treindl (2019-07-02):
 # I spent 6 Euros to buy two archive copies of Il Messaggero, a Roman paper,
 # for 1 and 2 April 1944.  The edition of 2 April has this note: "Tonight at 2
 # am, put forward the clock by one hour.  Remember that in the night between
 # today and Monday the 'ora legale' will come in force again."  That makes it
 # clear that in Rome the change was on Monday, 3 April 1944 at 2 am.
 #
-# From Paul Eggert (2016-10-27):
+# From Paul Eggert (2021-10-05):
 # Go with INRiM for DST rules, except as corrected by Inglis for 1944
 # for the Kingdom of Italy.  This is consistent with Renzo Baldini.
 # Model Rome's occupation by using C-Eur rules from 1943-09-10
 # to 1944-06-04; although Rome was an open city during this period, it
-# was effectively controlled by Germany.
+# was effectively controlled by Germany.  Using C-Eur is consistent
+# with Treindl's comment about Rome in April 1944, as the "Rule Italy"
+# lines during German occupation do not affect Europe/Rome
+# (though they do affect Europe/Malta).
 #
 # Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Italy	1916	only	-	Jun	 3	24:00	1:00	S
@@ -1801,6 +1803,10 @@ Zone	Europe/Rome	0:49:56 -	LMT	1866 Dec 12
 			1:00	Italy	CE%sT	1980
 			1:00	EU	CE%sT
 
+# Kosovo
+# See Europe/Belgrade.
+
+
 Link	Europe/Rome	Europe/Vatican
 Link	Europe/Rome	Europe/San_Marino
 
@@ -2151,6 +2157,10 @@ 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
@@ -2377,12 +2387,10 @@ 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
-Rule	Port	1947	1949	-	Oct	Sun>=1	 2:00s	0	-
-# Shanks & Pottenger say DST was observed in 1950; go with Whitman.
+# Whitman says DST was not observed in 1950; go with Shanks & Pottenger.
 # 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	1951	1965	-	Oct	Sun>=1	 2:00s	0	-
+Rule	Port	1947	1965	-	Apr	Sun>=1	 2:00s	1:00	S
+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
@@ -2619,7 +2627,7 @@ Zone Europe/Bucharest	1:44:24 -	LMT	1891 Oct
 # Although Shanks lists 1945-01-01 as the date for transition from
 # +01/+02 to +02/+03, more likely this is a placeholder.  Guess that
 # the transition occurred at 1945-04-10 00:00, which is about when
-# Königsberg surrendered to Soviet troops.  (Thanks to Alois Triendl.)
+# Königsberg surrendered to Soviet troops.  (Thanks to Alois Treindl.)
 
 # From Paul Eggert (2016-03-18):
 # The 1989 transition is from USSR act No. 227 (1989-03-14).
@@ -3684,6 +3692,9 @@ 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
diff --git a/share/zoneinfo/datfiles/leapseconds b/share/zoneinfo/datfiles/leapseconds
index 4d80d3abf62..f4977b0ea16 100644
--- a/share/zoneinfo/datfiles/leapseconds
+++ b/share/zoneinfo/datfiles/leapseconds
@@ -1,4 +1,4 @@
-# $OpenBSD: leapseconds,v 1.44 2021/01/24 20:18:50 millert Exp $
+# $OpenBSD: leapseconds,v 1.45 2021/10/22 14:40:49 millert Exp $
 # Allowance for leap seconds added to each time zone file.
 
 # This file is in the public domain.
@@ -73,11 +73,11 @@ 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
-#	File expires on:  28 December 2021
+#	Updated through IERS Bulletin C62
+#	File expires on:  28 June 2022
diff --git a/share/zoneinfo/datfiles/northamerica b/share/zoneinfo/datfiles/northamerica
index 304425197ad..60ff82c8e2d 100644
--- a/share/zoneinfo/datfiles/northamerica
+++ b/share/zoneinfo/datfiles/northamerica
@@ -1,4 +1,4 @@
-# $OpenBSD: northamerica,v 1.77 2020/12/23 13:06:28 millert Exp $
+# $OpenBSD: northamerica,v 1.78 2021/10/22 14:40:49 millert Exp $
 # tzdb data for North and Central America and environs
 
 # This file is in the public domain, so clarified as of
@@ -730,7 +730,11 @@ 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,
@@ -826,6 +830,8 @@ Zone America/Phoenix	-7:28:18 -	LMT	1883 Nov 18 11:31:42
 			-7:00	-	MST	1967
 			-7:00	US	M%sT	1968 Mar 21
 			-7:00	-	MST
+Link America/Phoenix America/Creston
+
 # From Arthur David Olson (1988-02-13):
 # A writer from the Inter Tribal Council of Arizona, Inc.,
 # notes in private correspondence dated 1987-12-28 that "Presently, only the
@@ -971,7 +977,7 @@ Zone America/Indiana/Vincennes -5:50:07 - LMT	1883 Nov 18 12:09:53
 			-5:00	US	E%sT
 #
 # Perry County, Indiana, switched from eastern to central time in April 2006.
-# From Alois Triendl (2019-07-09):
+# From Alois Treindl (2019-07-09):
 # The Indianapolis News, Friday 27 October 1967 states that Perry County
 # returned to CST.  It went again to EST on 27 April 1969, as documented by the
 # Indianapolis star of Saturday 26 April.
@@ -1594,24 +1600,7 @@ 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.
-#
-# 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
+# See America/Puerto_Rico for east of Natashquan.
 
 # Ontario
 
@@ -1650,54 +1639,6 @@ 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:
@@ -1828,6 +1769,7 @@ Zone America/Toronto	-5:17:32 -	LMT	1895
 			-5:00	Canada	E%sT	1946
 			-5:00	Toronto	E%sT	1974
 			-5:00	Canada	E%sT
+Link America/Toronto America/Nassau
 Zone America/Thunder_Bay -5:57:00 -	LMT	1895
 			-6:00	-	CST	1910
 			-5:00	-	EST	1942
@@ -1843,11 +1785,7 @@ 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
-			-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
+# For Atikokan see America/Panama.
 
 
 # Manitoba
@@ -1999,7 +1937,7 @@ Zone America/Swift_Current -7:11:20 -	LMT	1905 Sep
 
 # Alberta
 
-# From Alois Triendl (2019-07-19):
+# From Alois Treindl (2019-07-19):
 # There was no DST in Alberta in 1967... Calgary Herald, 29 April 1967.
 # 1969, no DST, from Edmonton Journal 18 April 1969
 #
@@ -2038,60 +1976,6 @@ 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
@@ -2108,7 +1992,7 @@ Zone America/Edmonton	-7:33:52 -	LMT	1906 Sep
 #
 # From Paul Eggert (2019-07-25):
 # Shanks says Fort Nelson did not observe DST in 1946, unlike Vancouver.
-# Alois Triendl confirmed this on 07-22, citing the 1946-04-27 Vancouver Daily
+# Alois Treindl confirmed this on 07-22, citing the 1946-04-27 Vancouver Daily
 # Province.  He also cited the 1946-09-28 Victoria Daily Times, which said
 # that Vancouver, Victoria, etc. "change at midnight Saturday"; for now,
 # guess they meant 02:00 Sunday since 02:00 was common practice in Vancouver.
@@ -2145,10 +2029,7 @@ 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
-			-7:00	-	MST	1916 Oct 1
-			-8:00	-	PST	1918 Jun 2
-			-7:00	-	MST
+# For Creston see America/Phoenix.
 
 # Northwest Territories, Nunavut, Yukon
 
@@ -2930,64 +2811,61 @@ 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
-#
-# 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
+# The Bahamas
+# See America/Toronto.
 
-# 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
-			-3:58:29 -	BMT	1932 # Bridgetown Mean Time
+Zone America/Barbados	-3:58:29 -	LMT	1911 Aug 28 # Bridgetown
+			-4:00	Barb	A%sT	1944
+			-4:00	Barb	AST/-0330 1945
 			-4:00	Barb	A%sT
 
 # Belize
@@ -3149,6 +3027,9 @@ 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.
 
@@ -3377,7 +3258,7 @@ 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
 
@@ -3429,7 +3310,7 @@ 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
 #
@@ -3616,7 +3497,7 @@ 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
 #
@@ -3688,6 +3569,7 @@ 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/Atikokan
 Link America/Panama America/Cayman
 
 # Puerto Rico
@@ -3697,10 +3579,29 @@ Zone America/Puerto_Rico -4:24:25 -	LMT	1899 Mar 28 12:00 # San Juan
 			-4:00	-	AST	1942 May  3
 			-4:00	US	A%sT	1946
 			-4:00	-	AST
+Link America/Puerto_Rico America/Anguilla
+Link America/Puerto_Rico America/Antigua
+Link America/Puerto_Rico America/Aruba
+Link America/Puerto_Rico America/Curacao
+Link America/Puerto_Rico America/Blanc-Sablon	# Quebec (Lower North Shore)
+Link America/Puerto_Rico America/Dominica
+Link America/Puerto_Rico America/Grenada
+Link America/Puerto_Rico America/Guadeloupe
+Link America/Puerto_Rico America/Kralendijk	# Caribbean Netherlands
+Link America/Puerto_Rico America/Lower_Princes	# Sint Maarten
+Link America/Puerto_Rico America/Marigot	# St Martin (French part)
+Link America/Puerto_Rico America/Montserrat
+Link America/Puerto_Rico America/Port_of_Spain	# Trinidad & Tobago
+Link America/Puerto_Rico America/St_Barthelemy	# St Barthélemy
+Link America/Puerto_Rico America/St_Kitts	# St Kitts & Nevis
+Link America/Puerto_Rico America/St_Lucia
+Link America/Puerto_Rico America/St_Thomas	# Virgin Islands (US)
+Link America/Puerto_Rico America/St_Vincent
+Link America/Puerto_Rico America/Tortola	# Virgin Islands (UK)
 
 # 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'.
@@ -3711,7 +3612,10 @@ 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
 #
@@ -3782,8 +3686,8 @@ Zone America/Grand_Turk	-4:44:32 -	LMT	1890
 			-5:00	US	E%sT
 
 # British Virgin Is
-# Virgin Is
-# See America/Port_of_Spain.
+# US Virgin Is
+# See America/Puerto_Rico.
 
 
 # Local Variables:
diff --git a/share/zoneinfo/datfiles/southamerica b/share/zoneinfo/datfiles/southamerica
index 1b8539efe67..f61b340c21a 100644
--- a/share/zoneinfo/datfiles/southamerica
+++ b/share/zoneinfo/datfiles/southamerica
@@ -1,4 +1,4 @@
-# $OpenBSD: southamerica,v 1.71 2020/10/07 22:33:32 millert Exp $
+# $OpenBSD: southamerica,v 1.72 2021/10/22 14:40:49 millert Exp $
 # tzdb data for South America and environs
 
 # This file is in the public domain, so clarified as of
@@ -575,7 +575,7 @@ 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]
@@ -1370,35 +1370,14 @@ Zone	America/Bogota	-4:56:16 -	LMT	1884 Mar 13
 # no information; probably like America/Bogota
 
 # 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.
+# See America/Puerto_Rico.
 #
-# 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.
-
-Link	America/Curacao	America/Lower_Princes	# Sint Maarten
-Link	America/Curacao	America/Kralendijk	# Caribbean Netherlands
+# and contains an apostrophe; use "Lower_Princes"....
+# From Paul Eggert (2021-09-29):
+# These backward-compatibility links now are in the 'northamerica' file.
 
 # Ecuador
 #
@@ -1541,11 +1520,40 @@ 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
-			-3:45	-	-0345	1975 Jul 31
-			-3:00	-	-03	1991
-# IATA SSIM (1996-06) says -4:00.  Assume a 1991 switch.
+Zone	America/Guyana	-3:52:39 -	LMT	1911 Aug  1 # Georgetown
+			-4:00	-	-04	1915 Mar  1
+			-3:45	-	-0345	1975 Aug  1
+			-3:00	-	-03	1992 Mar 29  1:00
 			-4:00	-	-04
 
 # Paraguay
@@ -1686,24 +1694,7 @@ Zone America/Paramaribo	-3:40:40 -	LMT	1911
 			-3:00	-	-03
 
 # Trinidad and Tobago
-# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-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)
+# See America/Puerto_Rico.
 
 # Uruguay
 # From Paul Eggert (1993-11-18):
diff --git a/share/zoneinfo/datfiles/zone.tab b/share/zoneinfo/datfiles/zone.tab
index fadb673097e..c97161e2c38 100644
--- a/share/zoneinfo/datfiles/zone.tab
+++ b/share/zoneinfo/datfiles/zone.tab
@@ -1,10 +1,10 @@
-# $OpenBSD: zone.tab,v 1.69 2020/12/23 13:06:28 millert Exp $
+# $OpenBSD: zone.tab,v 1.70 2021/10/22 14:40:49 millert Exp $
 # tzdb timezone descriptions (deprecated version)
 #
 # 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:
@@ -17,6 +17,9 @@
 # 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.
@@ -229,7 +232,7 @@ 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
@@ -392,7 +395,7 @@ 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
diff --git a/share/zoneinfo/datfiles/zone1970.tab b/share/zoneinfo/datfiles/zone1970.tab
index 396e4d3810b..c614be81f40 100644
--- a/share/zoneinfo/datfiles/zone1970.tab
+++ b/share/zoneinfo/datfiles/zone1970.tab
@@ -40,11 +40,9 @@ 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)
@@ -97,7 +95,6 @@ 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
@@ -106,13 +103,11 @@ 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	+4339-07923	America/Toronto	Eastern - ON, QC (most areas)
+CA,BS	+4339-07923	America/Toronto	Eastern - ON, QC (most areas), Bahamas
 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)
@@ -123,7 +118,6 @@ 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)
@@ -131,7 +125,7 @@ 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
@@ -142,7 +136,6 @@ 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
@@ -170,7 +163,6 @@ 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)
@@ -204,7 +196,7 @@ 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
@@ -262,19 +254,19 @@ 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)
@@ -314,12 +306,12 @@ 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
@@ -334,9 +326,8 @@ 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)
@@ -362,7 +353,7 @@ 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