--- contrib/tzdata/Makefile.orig
+++ contrib/tzdata/Makefile
@@ -35,11 +35,13 @@
 
 LOCALTIME=	GMT
 
-# If you want something other than Eastern United States time as a template
-# for handling ruleless POSIX-style timezone environment variables,
+# The POSIXRULES macro controls interpretation of nonstandard and obsolete
+# POSIX-like TZ settings like TZ='EET-2EEST' that lack DST transition rules.
+# In the reference implementation, if you want something other than Eastern
+# United States time as a template for handling these settings, you can
 # change the line below (after finding the timezone you want in the
 # one of the $(TDATA) source files, or adding it to a source file).
-# A ruleless environment setting like TZ='CST6CDT' uses the rules in the
+# A setting like TZ='EET-2EEST' is supposed to use the rules in the
 # template file to determine "spring forward" and "fall back" days and
 # times; the environment variable itself specifies UT offsets of standard and
 # daylight saving time.
@@ -49,6 +51,17 @@
 # Use the command
 #	make zonenames
 # to get a list of the values you can use for POSIXRULES.
+#
+# If POSIXRULES is empty, no template is installed; this is the intended
+# future default for POSIXRULES.
+#
+# Nonempty POSIXRULES is obsolete and should not be relied on, because:
+# * 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 is incompatible with 'zic -b slim' if POSIXRULES specifies transitions
+#   at standard time or UT rather than at local time.
+# In short, software should avoid ruleless settings like TZ='EET-2EEST'
+# and so should not depend on the value of POSIXRULES.
 
 POSIXRULES=	America/New_York
 
@@ -231,6 +244,13 @@
 #	other than simply getting garbage data
 #  -DUSE_LTZ=0 to build zdump with the system time zone library
 #	Also set TZDOBJS=zdump.o and CHECK_TIME_T_ALTERNATIVES= below.
+#  -DZIC_BLOAT_DEFAULT=\"slim\" to default zic's -b option to "slim", and
+#	similarly for "fat".  Fat TZif files work around incompatibilities
+#	and bugs in some TZif readers, notably readers that mishandle 64-bit
+#	data in TZif files.  Slim TZif files are more efficient and do not
+#	work around these incompatibilities and bugs.  If not given, the
+#	current default is "fat" but this is intended to change as readers
+#	requiring fat files often mishandle timestamps after 2037 anyway.
 #  -DZIC_MAX_ABBR_LEN_WO_WARN=3
 #	(or some other number) to set the maximum time zone abbreviation length
 #	that zic will accept without a warning (the default is 6)
@@ -364,7 +384,9 @@
 
 # To shrink the size of installed TZif files,
 # append "-r @N" to omit data before N-seconds-after-the-Epoch.
-# See the zic man page for more about -r.
+# You can also append "-b slim" if that is not already the default;
+# see ZIC_BLOAT_DEFAULT above.
+# See the zic man page for more about -b and -r.
 ZFLAGS=
 
 # How to use zic to install TZif files.
@@ -388,6 +410,9 @@
 # Name of curl <https://curl.haxx.se/>, used for HTML validation.
 CURL=		curl
 
+# Name of GNU Privacy Guard <https://gnupg.org/>, used to sign distributions.
+GPG=		gpg
+
 # The path where SGML DTDs are kept and the catalog file(s) to use when
 # validating HTML 4.01.  The default should work on both Debian and Red Hat.
 SGML_TOPDIR= /usr
@@ -562,7 +587,9 @@
 			'$(DESTDIR)$(LIBDIR)' \
 			'$(DESTDIR)$(MANDIR)/man3' '$(DESTDIR)$(MANDIR)/man5' \
 			'$(DESTDIR)$(MANDIR)/man8'
-		$(ZIC_INSTALL) -l $(LOCALTIME) -p $(POSIXRULES) \
+		$(ZIC_INSTALL) -l $(LOCALTIME) \
+			`case '$(POSIXRULES)' in ?*) echo '-p';; esac \
+			` $(POSIXRULES) \
 			-t '$(DESTDIR)$(TZDEFAULT)'
 		cp -f $(TABDATA) '$(DESTDIR)$(TZDIR)/.'
 		cp tzselect '$(DESTDIR)$(BINDIR)/.'
@@ -781,12 +808,6 @@
 check_sorted: backward backzone iso3166.tab zone.tab zone1970.tab
 		$(AWK) '/^Link/ {print $$3}' backward | LC_ALL=C sort -cu
 		$(AWK) '/^Zone/ {print $$2}' backzone | LC_ALL=C sort -cu
-		$(AWK) '/^[^#]/ {print $$1}' iso3166.tab | LC_ALL=C sort -cu
-		$(AWK) '/^[^#]/ {print $$1}' zone.tab | LC_ALL=C sort -c
-		$(AWK) '/^[^#]/ {print substr($$0, 1, 2)}' zone1970.tab | \
-		  LC_ALL=C sort -c
-		$(AWK) '/^[^#]/ $(CHECK_CC_LIST)' zone1970.tab | \
-		  LC_ALL=C sort -cu
 		touch $@
 
 check_links:	checklinks.awk $(TDATA_TO_CHECK) tzdata.zi
@@ -1051,7 +1072,7 @@
 tzdata$(VERSION)-rearguard.tar.gz.asc: tzdata$(VERSION)-rearguard.tar.gz
 tzdb-$(VERSION).tar.lz.asc: tzdb-$(VERSION).tar.lz
 $(ALL_ASC):
-		gpg2 --armor --detach-sign $?
+		$(GPG) --armor --detach-sign $?
 
 TYPECHECK_CFLAGS = $(CFLAGS) -DTYPECHECK -D__time_t_defined -D_TIME_T
 typecheck: typecheck_long_long typecheck_unsigned
--- contrib/tzdata/NEWS.orig
+++ contrib/tzdata/NEWS
@@ -1,8 +1,102 @@
 News for the tz database
 
-Release 20198 - 2019-03-25 22:01:33 -0700
+Release 2019b - 2019-07-01 00:09:53 -0700
 
   Briefly:
+    Brazil no longer observes DST.
+    'zic -b slim' outputs smaller TZif files; please try it out.
+    Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
+
+  Changes to future timestamps
+
+    Brazil has canceled DST and will stay on standard time indefinitely.
+    (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
+    Oliveira.)
+
+    Predictions for Morocco now go through 2087 instead of 2037, to
+    work around a problem on newlib when using TZif files output by
+    zic 2019a or earlier.  (Problem reported by David Gauchard.)
+
+  Changes to past and future timestamps
+
+    Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
+    at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
+    future transitions to be March's last Friday at 00:00.
+
+  Changes to past timestamps
+
+    Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
+    03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
+    not 09-15 at 00:00.  In 1946 its spring-forward transition was on
+    04-21 at 00:00, not the previous day at 03:30.  From 1946 through
+    1952 its fall-back transitions occurred at 04:30, not at 03:30.
+    In 1947 its fall-back transition was on 11-30, not 12-30.
+    (Thanks to P Chan.)
+
+  Changes to past time zone abbreviations
+
+    Italy's 1866 transition to Rome Mean Time was on December 12, not
+    September 22.  This affects only the time zone abbreviation for
+    Europe/Rome between those dates.  (Thanks to Stephen Trainor and
+    Luigi Rosa.)
+
+  Changes affecting metadata only
+
+    Add info about the Crimea situation in zone1970.tab and zone.tab.
+    (Problem reported by Serhii Demediuk.)
+
+  Changes to code
+
+    zic's new -b option supports a way to control data bloat and to
+    test for year-2038 bugs in software that reads TZif files.
+    'zic -b fat' and 'zic -b slim' generate larger and smaller output;
+    for example, changing from fat to slim shrinks the Europe/London
+    file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
+    files represent the same set of timestamps and use the same TZif
+    format as documented in tzfile(5) and in Internet RFC 8536.
+    Fat format attempts to work around bugs or incompatibilities in
+    older software, notably software that mishandles 64-bit TZif data
+    or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
+    Slim format is more efficient and does not work around 64-bit bugs
+    or obsolete TZ strings.  Currently zic defaults to fat format
+    unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
+    out-of-the-box default is intended to change in future releases
+    as the buggy software often mishandles timestamps anyway.
+
+    zic no longer treats a set of rules ending in 2037 specially.
+    Previously, zic assumed that such a ruleset meant that future
+    timestamps could not be predicted, and therefore omitted a
+    POSIX-like TZ string in the TZif output.  The old behavior is no
+    longer needed for current tzdata, and caused problems with newlib
+    when used with older tzdata (reported by David Gauchard).
+
+    zic no longer generates some artifact transitions.  For example,
+    Europe/London no longer has a no-op transition in January 1996.
+
+  Changes to build procedure
+
+    tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
+    by a percent or so.
+
+  Changes to documentation and commentary
+
+    The Makefile now documents the POSIXRULES macro as being obsolete,
+    and similarly, zic's -p POSIXRULES option is now documented as
+    being obsolete.  Although the POSIXRULES feature still exists and
+    works as before, in practice it is rarely used for its intended
+    purpose, and it does not work either in the default reference
+    implementation (for timestamps after 2037) or in common
+    implementations such as GNU/Linux (for contemporary timestamps).
+    Since POSIXRULES was designed primarily as a temporary transition
+    facility for System V platforms that died off decades ago, it is
+    being decommissioned rather than institutionalized.
+
+    New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
+
+
+Release 2019a - 2019-03-25 22:01:33 -0700
+
+  Briefly:
     Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
     Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
 
@@ -481,7 +575,7 @@
     The code is a bit more portable to MS-Windows.  Installers can
     compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
     reserve identifiers like 'localtime'.  (Thanks to Manuela
-    Friedrich).
+    Friedrich.)
 
   Changes to documentation and commentary
 
@@ -2276,7 +2370,7 @@
     warlord Jin Shuren in the data.
 
     Commentary about the coverage of each Russian zone has been standardized.
-    (Thanks to Tim Parenti).
+    (Thanks to Tim Parenti.)
 
     There is new commentary about contemporary timekeeping in Ethiopia.
 
@@ -2724,7 +2818,7 @@
 
     Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
     This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
-    to Alois Treindl).
+    to Alois Treindl.)
 
     Change the date of the circa-1850 Zurich transition from 1849-09-12
     to 1853-07-16, overriding Shanks with data from Messerli about
@@ -3034,7 +3128,7 @@
     (Thanks to Arthur David Olson.)
 
     Improve the commentary about which districts observe what times
-    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson).
+    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
 
     Add web page links to tz.js.
 
--- contrib/tzdata/africa.orig
+++ contrib/tzdata/africa
@@ -89,7 +89,7 @@
 Rule	Algeria	1980	only	-	Oct	31	 2:00	0	-
 # Shanks & Pottenger give 0:09:20 for Paris Mean Time; go with Howse's
 # more precise 0:09:21.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Algiers	0:12:12 -	LMT	1891 Mar 15  0:01
 			0:09:21	-	PMT	1911 Mar 11 # Paris Mean Time
 			0:00	Algeria	WE%sT	1940 Feb 25  2:00
@@ -124,7 +124,7 @@
 # For now, ignore that and follow the 1911-05-26 Portuguese decree
 # (see Europe/Lisbon).
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Atlantic/Cape_Verde -1:34:04 -	LMT	1912 Jan 01  2:00u # Praia
 			-2:00	-	-02	1942 Sep
 			-2:00	1:00	-01	1945 Oct 15
@@ -135,7 +135,7 @@
 # See Africa/Lagos.
 
 # Chad
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Ndjamena	1:00:12 -	LMT	1912        # N'Djamena
 			1:00	-	WAT	1979 Oct 14
 			1:00	1:00	WAST	1980 Mar  8
@@ -151,7 +151,7 @@
 # See Africa/Lagos.
 
 # Côte d'Ivoire / Ivory Coast
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Abidjan	-0:16:08 -	LMT	1912
 			 0:00	-	GMT
 Link Africa/Abidjan Africa/Bamako	# Mali
@@ -356,7 +356,7 @@
 Rule	Egypt	2014	only	-	Jul	31	24:00	1:00	S
 Rule	Egypt	2014	only	-	Sep	lastThu	24:00	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Cairo	2:05:09 -	LMT	1900 Oct
 			2:00	Egypt	EE%sT
 
@@ -414,7 +414,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Ghana	1920	1942	-	Sep	 1	0:00	0:20	-
 Rule	Ghana	1920	1942	-	Dec	31	0:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Accra	-0:00:52 -	LMT	1918
 			 0:00	Ghana	GMT/+0020
 
@@ -428,13 +428,13 @@
 # evidently confusing the date of the Portuguese decree
 # (see Europe/Lisbon) with the date that it took effect.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Bissau	-1:02:20 -	LMT	1912 Jan  1  1:00u
 			-1:00	-	-01	1975
 			 0:00	-	GMT
 
 # Kenya
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Nairobi	2:27:16	-	LMT	1928 Jul
 			3:00	-	EAT	1930
 			2:30	-	+0230	1940
@@ -469,7 +469,7 @@
 # Use the abbreviation "MMT" before 1972, as the more-accurate numeric
 # abbreviation "-004430" would be one byte over the POSIX limit.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Monrovia	-0:43:08 -	LMT	1882
 			-0:43:08 -	MMT	1919 Mar # Monrovia Mean Time
 			-0:44:30 -	MMT	1972 Jan 7 # approximately MMT
@@ -519,7 +519,7 @@
 Rule	Libya	1997	only	-	Oct	 4	0:00	0	-
 Rule	Libya	2013	only	-	Mar	lastFri	1:00	1:00	S
 Rule	Libya	2013	only	-	Oct	lastFri	2:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Tripoli	0:52:44 -	LMT	1920
 			1:00	Libya	CE%sT	1959
 			2:00	-	EET	1982
@@ -629,7 +629,7 @@
 Rule Mauritius	1983	only	-	Mar	21	0:00	0	-
 Rule Mauritius	2008	only	-	Oct	lastSun	2:00	1:00	-
 Rule Mauritius	2009	only	-	Mar	lastSun	2:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Indian/Mauritius	3:50:00 -	LMT	1907 # Port Louis
 			4:00 Mauritius	+04/+05
 # Agalega Is, Rodriguez
@@ -860,18 +860,24 @@
 # the week end after....  The government does not announce yet the decision
 # about this temporary change.  But it s 99% sure that it will be the case,
 # as in previous years.  An unofficial survey was done these days, showing
-# that 64% of asked peopke are ok for moving from +1 to +0 during Ramadan.
+# that 64% of asked people are ok for moving from +1 to +0 during Ramadan.
 # https://leconomiste.com/article/1035870-enquete-l-economiste-sunergia-64-des-marocains-plebiscitent-le-gmt-pendant-ramadan
+
+# From Naoufal Semlali (2019-04-16):
+# Morocco will be on GMT starting from Sunday, May 5th 2019 at 3am.
+# The switch to GMT+1 will occur on Sunday, June 9th 2019 at 2am....
+# http://fr.le360.ma/societe/voici-la-date-du-retour-a-lheure-legale-au-maroc-188222
 #
-# From Paul Eggert (2018-11-01):
-# For now, guess that Morocco will fall back at 03:00 the last Sunday
-# before Ramadan, and spring forward at 02:00 the first Sunday after
+# From Paul Eggert (2019-05-20):
+# This agrees with our 2018-11-01 guess that the Moroccan government
+# would continue the practice of falling back at 03:00 the last Sunday
+# before Ramadan, and of springing forward at 02:00 the first Sunday after
 # Ramadan, as this has been the practice since 2012.  To implement this,
-# transition dates for 2019 through 2037 were determined by running the
-# following program under GNU Emacs 26.1.
+# transition dates for 2019 through 2087 were determined by running the
+# following program under GNU Emacs 26.2.
 # (let ((islamic-year 1440))
 #   (require 'cal-islam)
-#   (while (< islamic-year 1460)
+#   (while (< islamic-year 1511)
 #     (let ((a (calendar-islamic-to-absolute (list 9 1 islamic-year)))
 #           (b (calendar-islamic-to-absolute (list 10 1 islamic-year)))
 #           (sunday 0))
@@ -970,8 +976,114 @@
 Rule	Morocco	2036	only	-	Nov	23	 2:00	0	-
 Rule	Morocco	2037	only	-	Oct	 4	 3:00	-1:00	-
 Rule	Morocco	2037	only	-	Nov	15	 2:00	0	-
+Rule	Morocco	2038	only	-	Sep	26	 3:00	-1:00	-
+Rule	Morocco	2038	only	-	Oct	31	 2:00	0	-
+Rule	Morocco	2039	only	-	Sep	18	 3:00	-1:00	-
+Rule	Morocco	2039	only	-	Oct	23	 2:00	0	-
+Rule	Morocco	2040	only	-	Sep	 2	 3:00	-1:00	-
+Rule	Morocco	2040	only	-	Oct	14	 2:00	0	-
+Rule	Morocco	2041	only	-	Aug	25	 3:00	-1:00	-
+Rule	Morocco	2041	only	-	Sep	29	 2:00	0	-
+Rule	Morocco	2042	only	-	Aug	10	 3:00	-1:00	-
+Rule	Morocco	2042	only	-	Sep	21	 2:00	0	-
+Rule	Morocco	2043	only	-	Aug	 2	 3:00	-1:00	-
+Rule	Morocco	2043	only	-	Sep	 6	 2:00	0	-
+Rule	Morocco	2044	only	-	Jul	24	 3:00	-1:00	-
+Rule	Morocco	2044	only	-	Aug	28	 2:00	0	-
+Rule	Morocco	2045	only	-	Jul	 9	 3:00	-1:00	-
+Rule	Morocco	2045	only	-	Aug	20	 2:00	0	-
+Rule	Morocco	2046	only	-	Jul	 1	 3:00	-1:00	-
+Rule	Morocco	2046	only	-	Aug	 5	 2:00	0	-
+Rule	Morocco	2047	only	-	Jun	23	 3:00	-1:00	-
+Rule	Morocco	2047	only	-	Jul	28	 2:00	0	-
+Rule	Morocco	2048	only	-	Jun	 7	 3:00	-1:00	-
+Rule	Morocco	2048	only	-	Jul	19	 2:00	0	-
+Rule	Morocco	2049	only	-	May	30	 3:00	-1:00	-
+Rule	Morocco	2049	only	-	Jul	 4	 2:00	0	-
+Rule	Morocco	2050	only	-	May	15	 3:00	-1:00	-
+Rule	Morocco	2050	only	-	Jun	26	 2:00	0	-
+Rule	Morocco	2051	only	-	May	 7	 3:00	-1:00	-
+Rule	Morocco	2051	only	-	Jun	11	 2:00	0	-
+Rule	Morocco	2052	only	-	Apr	28	 3:00	-1:00	-
+Rule	Morocco	2052	only	-	Jun	 2	 2:00	0	-
+Rule	Morocco	2053	only	-	Apr	13	 3:00	-1:00	-
+Rule	Morocco	2053	only	-	May	25	 2:00	0	-
+Rule	Morocco	2054	only	-	Apr	 5	 3:00	-1:00	-
+Rule	Morocco	2054	only	-	May	10	 2:00	0	-
+Rule	Morocco	2055	only	-	Mar	28	 3:00	-1:00	-
+Rule	Morocco	2055	only	-	May	 2	 2:00	0	-
+Rule	Morocco	2056	only	-	Mar	12	 3:00	-1:00	-
+Rule	Morocco	2056	only	-	Apr	23	 2:00	0	-
+Rule	Morocco	2057	only	-	Mar	 4	 3:00	-1:00	-
+Rule	Morocco	2057	only	-	Apr	 8	 2:00	0	-
+Rule	Morocco	2058	only	-	Feb	17	 3:00	-1:00	-
+Rule	Morocco	2058	only	-	Mar	31	 2:00	0	-
+Rule	Morocco	2059	only	-	Feb	 9	 3:00	-1:00	-
+Rule	Morocco	2059	only	-	Mar	16	 2:00	0	-
+Rule	Morocco	2060	only	-	Feb	 1	 3:00	-1:00	-
+Rule	Morocco	2060	only	-	Mar	 7	 2:00	0	-
+Rule	Morocco	2061	only	-	Jan	16	 3:00	-1:00	-
+Rule	Morocco	2061	only	-	Feb	27	 2:00	0	-
+Rule	Morocco	2062	only	-	Jan	 8	 3:00	-1:00	-
+Rule	Morocco	2062	only	-	Feb	12	 2:00	0	-
+Rule	Morocco	2062	only	-	Dec	31	 3:00	-1:00	-
+Rule	Morocco	2063	only	-	Feb	 4	 2:00	0	-
+Rule	Morocco	2063	only	-	Dec	16	 3:00	-1:00	-
+Rule	Morocco	2064	only	-	Jan	20	 2:00	0	-
+Rule	Morocco	2064	only	-	Dec	 7	 3:00	-1:00	-
+Rule	Morocco	2065	only	-	Jan	11	 2:00	0	-
+Rule	Morocco	2065	only	-	Nov	22	 3:00	-1:00	-
+Rule	Morocco	2066	only	-	Jan	 3	 2:00	0	-
+Rule	Morocco	2066	only	-	Nov	14	 3:00	-1:00	-
+Rule	Morocco	2066	only	-	Dec	19	 2:00	0	-
+Rule	Morocco	2067	only	-	Nov	 6	 3:00	-1:00	-
+Rule	Morocco	2067	only	-	Dec	11	 2:00	0	-
+Rule	Morocco	2068	only	-	Oct	21	 3:00	-1:00	-
+Rule	Morocco	2068	only	-	Dec	 2	 2:00	0	-
+Rule	Morocco	2069	only	-	Oct	13	 3:00	-1:00	-
+Rule	Morocco	2069	only	-	Nov	17	 2:00	0	-
+Rule	Morocco	2070	only	-	Oct	 5	 3:00	-1:00	-
+Rule	Morocco	2070	only	-	Nov	 9	 2:00	0	-
+Rule	Morocco	2071	only	-	Sep	20	 3:00	-1:00	-
+Rule	Morocco	2071	only	-	Oct	25	 2:00	0	-
+Rule	Morocco	2072	only	-	Sep	11	 3:00	-1:00	-
+Rule	Morocco	2072	only	-	Oct	16	 2:00	0	-
+Rule	Morocco	2073	only	-	Aug	27	 3:00	-1:00	-
+Rule	Morocco	2073	only	-	Oct	 8	 2:00	0	-
+Rule	Morocco	2074	only	-	Aug	19	 3:00	-1:00	-
+Rule	Morocco	2074	only	-	Sep	23	 2:00	0	-
+Rule	Morocco	2075	only	-	Aug	11	 3:00	-1:00	-
+Rule	Morocco	2075	only	-	Sep	15	 2:00	0	-
+Rule	Morocco	2076	only	-	Jul	26	 3:00	-1:00	-
+Rule	Morocco	2076	only	-	Sep	 6	 2:00	0	-
+Rule	Morocco	2077	only	-	Jul	18	 3:00	-1:00	-
+Rule	Morocco	2077	only	-	Aug	22	 2:00	0	-
+Rule	Morocco	2078	only	-	Jul	10	 3:00	-1:00	-
+Rule	Morocco	2078	only	-	Aug	14	 2:00	0	-
+Rule	Morocco	2079	only	-	Jun	25	 3:00	-1:00	-
+Rule	Morocco	2079	only	-	Jul	30	 2:00	0	-
+Rule	Morocco	2080	only	-	Jun	16	 3:00	-1:00	-
+Rule	Morocco	2080	only	-	Jul	21	 2:00	0	-
+Rule	Morocco	2081	only	-	Jun	 1	 3:00	-1:00	-
+Rule	Morocco	2081	only	-	Jul	13	 2:00	0	-
+Rule	Morocco	2082	only	-	May	24	 3:00	-1:00	-
+Rule	Morocco	2082	only	-	Jun	28	 2:00	0	-
+Rule	Morocco	2083	only	-	May	16	 3:00	-1:00	-
+Rule	Morocco	2083	only	-	Jun	20	 2:00	0	-
+Rule	Morocco	2084	only	-	Apr	30	 3:00	-1:00	-
+Rule	Morocco	2084	only	-	Jun	11	 2:00	0	-
+Rule	Morocco	2085	only	-	Apr	22	 3:00	-1:00	-
+Rule	Morocco	2085	only	-	May	27	 2:00	0	-
+Rule	Morocco	2086	only	-	Apr	14	 3:00	-1:00	-
+Rule	Morocco	2086	only	-	May	19	 2:00	0	-
+Rule	Morocco	2087	only	-	Mar	30	 3:00	-1:00	-
+Rule	Morocco	2087	only	-	May	 4	 2:00	0	-
+# For dates after the somewhat-arbitrary cutoff of 2087, assume that
+# Morocco will no longer observe DST.  At some point this table will
+# need to be extended, though quite possibly Morocco will change the
+# rules first.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Africa/Casablanca	-0:30:20 -	LMT	1913 Oct 26
 			 0:00	Morocco	+00/+01	1984 Mar 16
 			 1:00	-	+01	1986
@@ -1001,7 +1113,7 @@
 # https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
 # merely made it official?
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Maputo	2:10:20 -	LMT	1903 Mar
 			2:00	-	CAT
 Link Africa/Maputo Africa/Blantyre	# Malawi
@@ -1073,7 +1185,7 @@
 #Rule	Namibia	1995	2017	-	Apr	Sun>=1	2:00	0	WAT
 # End of rearguard section.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Windhoek	1:08:24 -	LMT	1892 Feb 8
 			1:30	-	+0130	1903 Mar
 			2:00	-	SAST	1942 Sep 20  2:00
@@ -1094,7 +1206,7 @@
 # See Africa/Lagos.
 
 # Nigeria
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Lagos	0:13:36 -	LMT	1919 Sep
 			1:00	-	WAT
 Link Africa/Lagos Africa/Bangui	     # Central African Republic
@@ -1108,7 +1220,7 @@
 Link Africa/Lagos Africa/Porto-Novo  # Benin
 
 # Réunion
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Reunion	3:41:52 -	LMT	1911 Jun # Saint-Denis
 			4:00	-	+04
 #
@@ -1168,7 +1280,7 @@
 # See Africa/Abidjan.
 
 # Seychelles
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Mahe	3:41:48 -	LMT	1906 Jun # Victoria
 			4:00	-	+04
 # From Paul Eggert (2001-05-30):
@@ -1188,7 +1300,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	SA	1942	1943	-	Sep	Sun>=15	2:00	1:00	-
 Rule	SA	1943	1944	-	Mar	Sun>=15	2:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Africa/Johannesburg 1:52:00 -	LMT	1892 Feb 8
 			1:30	-	SAST	1903 Mar
 			2:00	SA	SAST
@@ -1223,7 +1335,7 @@
 Rule	Sudan	1970	1985	-	Oct	15	0:00	0	-
 Rule	Sudan	1971	only	-	Apr	30	0:00	1:00	S
 Rule	Sudan	1972	1985	-	Apr	lastSun	0:00	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Khartoum	2:10:08 -	LMT	1931
 			2:00	Sudan	CA%sT	2000 Jan 15 12:00
 			3:00	-	EAT	2017 Nov  1
@@ -1230,7 +1342,7 @@
 			2:00	-	CAT
 
 # South Sudan
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Juba	2:06:28 -	LMT	1931
 			2:00	Sudan	CA%sT	2000 Jan 15 12:00
 			3:00	-	EAT
@@ -1336,7 +1448,7 @@
 # Shanks & Pottenger give 0:09:20 for Paris Mean Time; go with Howse's
 # more precise 0:09:21.
 # Shanks & Pottenger say the 1911 switch was on Mar 9; go with Howse's Mar 11.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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
 			1:00	Tunisia	CE%sT
--- contrib/tzdata/antarctica.orig
+++ contrib/tzdata/antarctica
@@ -13,7 +13,7 @@
 # for information.
 # Unless otherwise specified, we have no time zone information.
 
-# FORMAT is '-00' and GMTOFF is 0 for locations while uninhabited.
+# FORMAT is '-00' and STDOFF is 0 for locations while uninhabited.
 
 # Argentina - year-round bases
 # Belgrano II, Confin Coast, -770227-0343737, since 1972-02-05
@@ -70,7 +70,7 @@
 # Australian Antarctica Division informed us that Casey changed time
 # zone to UTC+11 in "the morning of 22nd October 2016".
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/Casey	0	-	-00	1969
 			8:00	-	+08	2009 Oct 18  2:00
 			11:00	-	+11	2010 Mar  5  2:00
@@ -142,7 +142,7 @@
 # St Paul Island - near Amsterdam, uninhabited
 #	fishing stations operated variously 1819/1931
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Indian/Kerguelen	0	-	-00	1950 # Port-aux-Français
 			5:00	-	+05
 #
@@ -153,7 +153,7 @@
 # Another base at Port-Martin, 50km east, began operation in 1947.
 # It was destroyed by fire on 1952-01-14.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/DumontDUrville 0 -	-00	1947
 			10:00	-	+10	1952 Jan 14
 			0	-	-00	1956 Nov
@@ -181,7 +181,7 @@
 # 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		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/Syowa	0	-	-00	1957 Jan 29
 			3:00	-	+03
 # See:
@@ -231,7 +231,7 @@
 #Rule	Troll	2004	max	-	Nov	 7	1:00u	0:00	+00
 # Remove the following line when uncommenting the above '#Rule' lines.
 Rule	Troll	2004	max	-	Oct	lastSun	1:00u	0:00	+00
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/Troll	0	-	-00	2005 Feb 12
 			0:00	Troll	%s
 
@@ -305,7 +305,7 @@
 # From Paul Eggert (2002-10-22)
 # <http://webexhibits.org/daylightsaving/g.html> says Rothera is -03 all year.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/Rothera	0	-	-00	1976 Dec  1
 			-3:00	-	-03
 
--- contrib/tzdata/asia.orig
+++ contrib/tzdata/asia
@@ -84,7 +84,7 @@
 Rule RussiaAsia	1996	2010	-	Oct	lastSun	 2:00s	0	-
 
 # Afghanistan
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Kabul	4:36:48 -	LMT	1890
 			4:00	-	+04	1945
 			4:30	-	+0430
@@ -117,7 +117,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule Armenia	2011	only	-	Mar	lastSun	 2:00s	1:00	-
 Rule Armenia	2011	only	-	Oct	lastSun	 2:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Yerevan	2:58:00 -	LMT	1924 May  2
 			3:00	-	+03	1957 Mar
 			4:00 RussiaAsia +04/+05	1991 Mar 31  2:00s
@@ -143,7 +143,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Azer	1997	2015	-	Mar	lastSun	 4:00	1:00	-
 Rule	Azer	1997	2015	-	Oct	lastSun	 5:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Baku	3:19:24 -	LMT	1924 May  2
 			3:00	-	+03	1957 Mar
 			4:00 RussiaAsia +04/+05	1991 Mar 31  2:00s
@@ -231,7 +231,7 @@
 Rule	Dhaka	2009	only	-	Jun	19	23:00	1:00	-
 Rule	Dhaka	2009	only	-	Dec	31	24:00	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Dhaka	6:01:40 -	LMT	1890
 			5:53:20	-	HMT	1941 Oct    # Howrah Mean Time?
 			6:30	-	+0630	1942 May 15
@@ -241,7 +241,7 @@
 			6:00	Dhaka	+06/+07
 
 # Bhutan
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Thimphu	5:58:36 -	LMT	1947 Aug 15 # or Thimbu
 			5:30	-	+0530	1987 Oct
 			6:00	-	+06
@@ -252,13 +252,13 @@
 # We have no information as to when standard time was introduced;
 # assume it occurred in 1907, the same year as Mauritius (which
 # then contained the Chagos Archipelago).
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Chagos	4:49:40	-	LMT	1907
 			5:00	-	+05	1996
 			6:00	-	+06
 
 # Brunei
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Brunei	7:39:40 -	LMT	1926 Mar # Bandar Seri Begawan
 			7:30	-	+0730	1933
 			8:00	-	+08
@@ -273,7 +273,7 @@
 # of Greenwich."  This refers to the period before Burma's transition to +0630,
 # a transition for which Shanks is the only source.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Yangon	6:24:47 -	LMT	1880        # or Rangoon
 			6:24:47	-	RMT	1920        # Rangoon local time
 			6:30	-	+0630	1942 May
@@ -561,7 +561,7 @@
 # that the sort of users who prefer Asia/Urumqi now typically ignored the
 # +08 mandate back then.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # Beijing time, used throughout China; represented by Shanghai.
 Zone	Asia/Shanghai	8:05:43	-	LMT	1901
 			8:00	Shang	C%sT	1949 May 28
@@ -652,11 +652,41 @@
 #   https://i.imgur.com/05KkvtC.png
 # * 1941-09-30, Hong Kong Daily Press, Winter Time Warning.
 #   https://i.imgur.com/dge4kFJ.png
-# Also, the Liberation day of Hong Kong after WWII which British rule
-# over the territory resumed was August 30, 1945, which I think should
-# be the termination date for the use of JST in the territory....
 
-# From Paul Eggert (2018-11-17):
+# From P Chan (2018-12-31):
+# * According to the Hong Kong Daylight-Saving Regulations, 1941, the
+#   1941 spring-forward transition was at 03:00.
+#	http://sunzi.lib.hku.hk/hkgro/view/g1941/304271.pdf
+#	http://sunzi.lib.hku.hk/hkgro/view/g1941/305516.pdf
+# * According to some articles from South China Morning Post, +08 was
+#   resumed on 1945-11-18 at 02:00.
+#	https://i.imgur.com/M2IsZ3c.png
+#	https://i.imgur.com/iOPqrVo.png
+#	https://i.imgur.com/fffcGDs.png
+# * Some newspapers ... said the 1946 spring-forward transition was on
+#   04-21 at 00:00.  The Kung Sheung Evening News 1946-04-20 (Chinese)
+#	https://i.imgur.com/ZSzent0.png
+#	https://mmis.hkpl.gov.hk///c/portal/cover?c=QF757YsWv5%2FH7zGe%2FKF%2BFLYsuqGhRBfe p.4
+#   The Kung Sheung Daily News 1946-04-21 (Chinese)
+#	https://i.imgur.com/7ecmRlcm.png
+#	https://mmis.hkpl.gov.hk///c/portal/cover?c=QF757YsWv5%2BQBGt1%2BwUj5qG2GqtwR3Wh p.4
+# * According to the Summer Time Ordinance (1946), the fallback
+#   transitions between 1946 and 1952 were at 03:30 Standard Time (+08)
+#	http://oelawhk.lib.hku.hk/archive/files/bb74b06a74d5294620a15de560ab33c6.pdf
+# * Some other laws and regulations related to DST from 1953 to 1979
+#   Summer Time Ordinance 1953
+#	https://i.imgur.com/IOlJMav.jpg
+#   Summer Time (Amendment) Ordinance 1965
+#	https://i.imgur.com/8rofeLa.jpg
+#   Interpretation and General Clauses Ordinance (1966)
+#	https://i.imgur.com/joy3msj.jpg
+#   Emergency (Summer Time) Regulation 1973 <https://i.imgur.com/OpRWrKz.jpg>
+#   Interpretation and General Clauses (Amendment) Ordinance 1977
+#	https://i.imgur.com/RaNqnc4.jpg
+#   Resolution of the Legislative Council passed on 9 May 1979
+#	https://www.legco.gov.hk/yr78-79/english/lc_sitg/hansard/h790509.pdf#page=39
+
+# From Paul Eggert (2019-05-31):
 # Here are the dates given at
 # https://www.hko.gov.hk/gts/time/Summertime.htm
 # as of 2014-06-19:
@@ -667,7 +697,7 @@
 # 1944        Whole year
 # 1945        Whole year
 # 1946        20 Apr to 1 Dec
-# 1947        13 Apr to 30 Dec
+# 1947        13 Apr to 30 Nov
 # 1948        2 May to 31 Oct
 # 1949        3 Apr to 30 Oct
 # 1950        2 Apr to 29 Oct
@@ -704,36 +734,28 @@
 # The page does not give times of day for transitions,
 # or dates for the 1942 and 1945 transitions.
 # The Japanese occupation of Hong Kong began 1941-12-25.
-# The Japanese surrender of Hong Kong was signed 1945-09-16; see:
-# Heaver S. The days after the Pacific war ended: unsettling times
-# in Hong Kong. Post Magazine. 2016-06-13.
-# https://www.scmp.com/magazines/post-magazine/article/1852990/days-after-pacific-war-ended-unsettling-times-hong-kong
-# For lack of anything better, use start of those days as the
-# transition times.
 
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	HK	1946	only	-	Apr	20	3:30	1:00	S
-Rule	HK	1946	only	-	Dec	1	3:30	0	-
-Rule	HK	1947	only	-	Apr	13	3:30	1:00	S
-Rule	HK	1947	only	-	Dec	30	3:30	0	-
-Rule	HK	1948	only	-	May	2	3:30	1:00	S
-Rule	HK	1948	1951	-	Oct	lastSun	3:30	0	-
-Rule	HK	1952	1953	-	Nov	Sun>=1	3:30	0	-
+Rule	HK	1946	only	-	Apr	21	0:00	1:00	S
+Rule	HK	1946	only	-	Dec	1	3:30s	0	-
+Rule	HK	1947	only	-	Apr	13	3:30s	1:00	S
+Rule	HK	1947	only	-	Nov	30	3:30s	0	-
+Rule	HK	1948	only	-	May	2	3:30s	1:00	S
+Rule	HK	1948	1952	-	Oct	Sun>=28	3:30s	0	-
 Rule	HK	1949	1953	-	Apr	Sun>=1	3:30	1:00	S
+Rule	HK	1953	1964	-	Oct	Sun>=31	3:30	0	-
 Rule	HK	1954	1964	-	Mar	Sun>=18	3:30	1:00	S
-Rule	HK	1954	only	-	Oct	31	3:30	0	-
-Rule	HK	1955	1964	-	Nov	Sun>=1	3:30	0	-
 Rule	HK	1965	1976	-	Apr	Sun>=16	3:30	1:00	S
 Rule	HK	1965	1976	-	Oct	Sun>=16	3:30	0	-
 Rule	HK	1973	only	-	Dec	30	3:30	1:00	S
-Rule	HK	1979	only	-	May	Sun>=8	3:30	1:00	S
-Rule	HK	1979	only	-	Oct	Sun>=16	3:30	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+Rule	HK	1979	only	-	May	13	3:30	1:00	S
+Rule	HK	1979	only	-	Oct	21	3:30	0	-
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Hong_Kong	7:36:42 -	LMT	1904 Oct 30  0:36:42
-			8:00	-	HKT	1941 Jun 15  3:30
+			8:00	-	HKT	1941 Jun 15  3:00
 			8:00	1:00	HKST	1941 Oct  1  4:00
 			8:30	-	HKT	1941 Dec 25
-			9:00	-	JST	1945 Sep 16
+			9:00	-	JST	1945 Nov 18  2:00
 			8:00	HK	HK%sT
 
 ###############################################################################
@@ -857,7 +879,7 @@
 Rule	Taiwan	1979	only	-	Jul	1	0:00	1:00	D
 Rule	Taiwan	1979	only	-	Oct	1	0:00	0	S
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # Taipei or Taibei or T'ai-pei
 Zone	Asia/Taipei	8:06:00 -	LMT	1896 Jan  1
 			8:00	-	CST	1937 Oct  1
@@ -995,7 +1017,7 @@
 Rule	Macau	1979	only	-	May	13	03:30	1:00	D
 Rule	Macau	1979	only	-	Oct	Sun>=16	03:30	0	S
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Macau	7:34:10 -	LMT	1904 Oct 30
 			8:00	-	CST	1941 Dec 21 23:00
 			9:00	Macau	+09/+10	1945 Sep 30 24:00
@@ -1034,7 +1056,7 @@
 Rule	Cyprus	1978	only	-	Oct	2	0:00	0	-
 Rule	Cyprus	1979	1997	-	Sep	lastSun	0:00	0	-
 Rule	Cyprus	1981	1998	-	Mar	lastSun	0:00	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Nicosia	2:13:28 -	LMT	1921 Nov 14
 			2:00	Cyprus	EE%sT	1998 Sep
 			2:00	EUAsia	EE%sT
@@ -1083,7 +1105,7 @@
 # Byalokoz 1919 says Georgia was 2:59:11.
 # Go with Byalokoz.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Tbilisi	2:59:11 -	LMT	1880
 			2:59:11	-	TBMT	1924 May  2 # Tbilisi Mean Time
 			3:00	-	+03	1957 Mar
@@ -1120,7 +1142,7 @@
 # which will be permanent, with no seasonal adjustment, will happen at
 # midnight on Saturday, September 16.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Dili	8:22:20 -	LMT	1912 Jan  1
 			8:00	-	+08	1942 Feb 21 23:00
 			9:00	-	+09	1976 May  3
@@ -1186,7 +1208,7 @@
 # time for 1870-1941.  Shanks is our only (and dubious) source for the
 # 1941-1945 data.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Kolkata	5:53:28 -	LMT	1854 Jun 28 # Kolkata
 			5:53:20	-	HMT	1870	    # Howrah Mean Time?
 			5:21:10	-	MMT	1906 Jan  1 # Madras local time
@@ -1238,7 +1260,7 @@
 # WITA - +08 - Waktu Indonesia Tengah (Indonesia central time)
 # WIT  - +09 - Waktu Indonesia Timur (Indonesia eastern time)
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # Java, Sumatra
 Zone Asia/Jakarta	7:07:12 -	LMT	1867 Aug 10
 # Shanks & Pottenger say the next transition was at 1924 Jan 1 0:13,
@@ -1314,9 +1336,9 @@
 # I used the following code in GNU Emacs 26.1 to generate the "Rule Iran"
 # lines from 2008 through 2087.  Emacs 26.1 uses Ed Reingold's
 # cal-persia implementation of Birashk's approximation, which in the
-# 2008-2087 range disagrees with the the astronomical Persian calendar
-# for Persian years 1404 (Gregorian 2025) and 1437 (Gregorian 2058),
-# so the following code special-case those years.  See Table 15.1, page 264, of:
+# 2008-2087 range disagrees with the astronomical Persian calendar
+# for Persian years 1404 (Gregorian 2025) and 1437 (Gregorian 2058), so
+# the following code special-cases those years.  See Table 15.1, page 264, of:
 # Edward M. Reingold and Nachum Dershowitz, Calendrical Calculations:
 # The Ultimate Edition, Cambridge University Press (2018).
 # https://www.cambridge.org/fr/academic/subjects/computer-science/computing-general-interest/calendrical-calculations-ultimate-edition-4th-edition
@@ -1510,7 +1532,7 @@
 Rule	Iran	2088	max	-	Mar	20	24:00	1:00	-
 Rule	Iran	2088	max	-	Sep	20	24:00	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Tehran	3:25:44	-	LMT	1916
 			3:25:44	-	TMT	1946     # Tehran Mean Time
 			3:30	-	+0330	1977 Nov
@@ -1555,7 +1577,7 @@
 #
 Rule	Iraq	1991	2007	-	Apr	 1	3:00s	1:00	-
 Rule	Iraq	1991	2007	-	Oct	 1	3:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Baghdad	2:57:40	-	LMT	1890
 			2:57:36	-	BMT	1918     # Baghdad Mean Time?
 			3:00	-	+03	1982 May
@@ -1622,7 +1644,7 @@
 Rule	Zion	1975	only	-	Aug	31	0:00	0	S
 
 # From Alois Treindl (2019-03-06):
-# http://www.moin.gov.il/Documents/שעון קיץ/clock-50-years-7-2014.pdf
+# http://www.moin.gov.il/Documents/שעון%20קיץ/clock-50-years-7-2014.pdf
 # From Isaac Starkman (2019-03-06):
 # Summer time was in that period in 1980 and 1984, see
 # https://www.ynet.co.il/articles/0,7340,L-3951073,00.html
@@ -1760,32 +1782,15 @@
 #
 #	ftp://ftp.cs.huji.ac.il/pub/tz/announcements/2005+beyond.ps
 
-# From Paul Eggert (2012-10-26):
-# I used Ephraim Silverberg's dst-israel.el program
-# <ftp://ftp.cs.huji.ac.il/pub/tz/software/dst-israel.el> (2005-02-20)
-# along with Ed Reingold's cal-hebrew in GNU Emacs 21.4,
-# to generate the transitions from 2005 through 2012.
-# (I replaced "lastFri" with "Fri>=26" by hand.)
-# The spring transitions all correspond to the following Rule:
-#
-# Rule	Zion	2005	2012	-	Mar	Fri>=26	2:00	1:00	D
-#
-# but older zic implementations (e.g., Solaris 8) do not support
-# "Fri>=26" to mean April 1 in years like 2005, so for now we list the
-# springtime transitions explicitly.
-
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	Zion	2005	only	-	Apr	 1	2:00	1:00	D
+Rule	Zion	2005	2012	-	Apr	Fri<=1	2:00	1:00	D
 Rule	Zion	2005	only	-	Oct	 9	2:00	0	S
-Rule	Zion	2006	2010	-	Mar	Fri>=26	2:00	1:00	D
 Rule	Zion	2006	only	-	Oct	 1	2:00	0	S
 Rule	Zion	2007	only	-	Sep	16	2:00	0	S
 Rule	Zion	2008	only	-	Oct	 5	2:00	0	S
 Rule	Zion	2009	only	-	Sep	27	2:00	0	S
 Rule	Zion	2010	only	-	Sep	12	2:00	0	S
-Rule	Zion	2011	only	-	Apr	 1	2:00	1:00	D
 Rule	Zion	2011	only	-	Oct	 2	2:00	0	S
-Rule	Zion	2012	only	-	Mar	Fri>=26	2:00	1:00	D
 Rule	Zion	2012	only	-	Sep	23	2:00	0	S
 
 # From Ephraim Silverberg (2013-06-27):
@@ -1801,7 +1806,7 @@
 Rule	Zion	2013	max	-	Mar	Fri>=23	2:00	1:00	D
 Rule	Zion	2013	max	-	Oct	lastSun	2:00	0	S
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Jerusalem	2:20:54 -	LMT	1880
 			2:20:40	-	JMT	1918 # Jerusalem Mean Time?
 			2:00	Zion	I%sT
@@ -1893,7 +1898,7 @@
 # Central Time (UT+9). The adoption began on Oct 1, 1937.
 # https://ja.wikisource.org/wiki/明治二十八年勅令第百六十七號標準時ニ關スル件中改正ノ件
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Tokyo	9:18:59	-	LMT	1887 Dec 31 15:00u
 			9:00	Japan	J%sT
 # Since 1938, all Japanese possessions have been like Asia/Tokyo,
@@ -1996,7 +2001,7 @@
 Rule	Jordan	2013	only	-	Dec	20	0:00	0	-
 Rule	Jordan	2014	max	-	Mar	lastThu	24:00	1:00	S
 Rule	Jordan	2014	max	-	Oct	lastFri	0:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Amman	2:23:44 -	LMT	1931
 			2:00	Jordan	EE%sT
 
@@ -2037,8 +2042,8 @@
 # text.
 #
 # According to Izvestia newspaper No. 68 (23334) from 1991-03-20
-# (page 6; available at http://libinfo.org/newsr/newsr2574.djvu via
-# http://libinfo.org/index.php?id=58564) on 1991-03-31 at 2:00 during
+# -- page 6; available at http://libinfo.org/newsr/newsr2574.djvu via
+# http://libinfo.org/index.php?id=58564 -- on 1991-03-31 at 2:00 during
 # transition to "summer" time:
 # Republic of Georgia, Latvian SSR, Lithuanian SSR, SSR Moldova,
 # Estonian SSR; Komi ASSR; Kaliningrad oblast; Nenets autonomous okrug
@@ -2054,7 +2059,7 @@
 # Apparently there were last minute changes. Apparently Kazakh act No. 170
 # was one of such changes.
 #
-# https://ru.wikipedia.org/wiki/Декретное время
+# https://ru.wikipedia.org/wiki/Декретное_время
 # claims that Sovetskaya Rossiya newspaper on 1991-03-29 published that
 # Nenets autonomous okrug, Komi and Kazakhstan (excluding Uralsk oblast)
 # were to not move clocks and Uralsk oblast was to move clocks
@@ -2193,7 +2198,7 @@
 # UTC+6 to UTC+5 effective December 21st, 2018. The legal document is
 # located here: http://adilet.zan.kz/rus/docs/P1800000817 (russian language).
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 #
 # Almaty (formerly Alma-Ata), representing most locations in Kazakhstan
 # This includes KZ-AKM, KZ-ALA, KZ-ALM, KZ-AST, KZ-BAY, KZ-VOS, KZ-ZHA,
@@ -2295,7 +2300,7 @@
 Rule	Kyrgyz	1992	1996	-	Sep	lastSun	0:00	0	-
 Rule	Kyrgyz	1997	2005	-	Mar	lastSun	2:30	1:00	-
 Rule	Kyrgyz	1997	2004	-	Oct	lastSun	2:30	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Bishkek	4:58:24 -	LMT	1924 May  2
 			5:00	-	+05	1930 Jun 21
 			6:00 RussiaAsia +06/+07	1991 Mar 31  2:00s
@@ -2410,7 +2415,7 @@
 # The BBC reported that the transition was from 23:30 to 24:00 today.
 # https://www.bbc.com/news/world-asia-44010705
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Seoul	8:27:52	-	LMT	1908 Apr  1
 			8:30	-	KST	1912 Jan  1
 			9:00	-	JST	1945 Sep  8
@@ -2459,7 +2464,7 @@
 Rule	Lebanon	1993	max	-	Mar	lastSun	0:00	1:00	S
 Rule	Lebanon	1993	1998	-	Sep	lastSun	0:00	0	-
 Rule	Lebanon	1999	max	-	Oct	lastSun	0:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Beirut	2:22:00 -	LMT	1880
 			2:00	Lebanon	EE%sT
 
@@ -2471,7 +2476,7 @@
 # peninsular Malaysia
 # taken from Mok Ly Yng (2003-10-30)
 # http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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.
 			7:00	-	+07	1933 Jan  1
@@ -2485,7 +2490,7 @@
 # From Paul Eggert (2014-08-12):
 # The data entries here are mostly from Shanks & Pottenger, but the 1942, 1945
 # and 1982 transition dates are from Mok Ly Yng.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Asia/Kuching	7:21:20	-	LMT	1926 Mar
 			7:30	-	+0730	1933
 			8:00 NBorneo  +08/+0820	1942 Feb 16
@@ -2493,7 +2498,7 @@
 			8:00	-	+08
 
 # Maldives
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Maldives	4:54:00 -	LMT	1880 # Malé
 			4:54:00	-	MMT	1960 # Malé Mean Time
 			5:00	-	+05
@@ -2636,7 +2641,7 @@
 Rule	Mongol	2015	2016	-	Mar	lastSat	2:00	1:00	-
 Rule	Mongol	2015	2016	-	Sep	lastSat	0:00	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # Hovd, a.k.a. Chovd, Dund-Us, Dzhargalant, Khovd, Jirgalanta
 Zone	Asia/Hovd	6:06:36 -	LMT	1905 Aug
 			6:00	-	+06	1978
@@ -2654,7 +2659,7 @@
 			8:00	Mongol	+08/+09
 
 # Nepal
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Kathmandu	5:41:16 -	LMT	1920
 			5:30	-	+0530	1986
 			5:45	-	+0545
@@ -2804,7 +2809,7 @@
 Rule Pakistan	2008	2009	-	Nov	1	0:00	0	-
 Rule Pakistan	2009	only	-	Apr	15	0:00	1:00	S
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Karachi	4:28:12 -	LMT	1907
 			5:30	-	+0530	1942 Sep
 			5:30	1:00	+0630	1945 Oct 15
@@ -3091,13 +3096,21 @@
 # http://www.palestinecabinet.gov.ps/Website/AR/NDecrees/ViewFile.ashx?ID=e7a42ab7-ee23-435a-b9c8-a4f7e81f3817
 
 # From Even Scharning (2019-03-23):
-# DST in Palestine will start on 30 March this year, not 23 March as the time
-# zone database predicted.
-# https://ramallah.news/post/123610
+# http://pnn.ps/news/401130
+# http://palweather.ps/ar/node/50136.html
 #
-# From Tim Parenti (2019-03-23):
-# Combining this with the rules observed since 2016, adjust our spring
-# transition guess to Mar Sat>=24.
+# From Sharif Mustafa (2019-03-26):
+# The Palestinian cabinet announced today that the switch to DST will
+# be on Fri Mar 29th 2019 by advancing the clock by 60 minutes.
+# The decree signing date is Mar 12th but it was not published till today.
+# The decree does not specify the exact time of switch.
+# http://palestinecabinet.gov.ps/Website/AR/NDecrees/ViewFile.ashx?ID=e54e9ea1-50ee-4137-84df-0d6c78da259b
+#
+# From Even Scharning (2019-04-10):
+# Our source in Palestine said it happened Friday 29 at 00:00 local time....
+#
+# From Paul Eggert (2019-04-10):
+# For now, guess spring-ahead transitions are March's last Friday at 00:00.
 
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule EgyptAsia	1957	only	-	May	10	0:00	1:00	S
@@ -3128,10 +3141,11 @@
 Rule Palestine	2013	only	-	Sep	Fri>=21	0:00	0	-
 Rule Palestine	2014	2015	-	Oct	Fri>=21	0:00	0	-
 Rule Palestine	2015	only	-	Mar	lastFri	24:00	1:00	S
-Rule Palestine	2016	max	-	Mar	Sat>=24	1:00	1:00	S
+Rule Palestine	2016	2018	-	Mar	Sat>=24	1:00	1:00	S
 Rule Palestine	2016	max	-	Oct	lastSat	1:00	0	-
+Rule Palestine	2019	max	-	Mar	lastFri	0:00	1:00	S
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Gaza	2:17:52	-	LMT	1900 Oct
 			2:00	Zion	EET/EEST 1948 May 15
 			2:00 EgyptAsia	EE%sT	1967 Jun  5
@@ -3205,7 +3219,7 @@
 Rule	Phil	1954	only	-	Jul	1	0:00	0	S
 Rule	Phil	1978	only	-	Mar	22	0:00	1:00	D
 Rule	Phil	1978	only	-	Sep	21	0:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Manila	-15:56:00 -	LMT	1844 Dec 31
 			8:04:00 -	LMT	1899 May 11
 			8:00	Phil	P%sT	1942 May
@@ -3213,7 +3227,7 @@
 			8:00	Phil	P%sT
 
 # Qatar
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Qatar	3:26:08 -	LMT	1920     # Al Dawhah / Doha
 			4:00	-	+04	1972 Jun
 			3:00	-	+03
@@ -3261,7 +3275,7 @@
 # the country.  Presumably this is documenting airline time.  Ignore this,
 # as it's before our 1970 cutoff.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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
@@ -3270,7 +3284,7 @@
 # Singapore
 # taken from Mok Ly Yng (2003-10-30)
 # http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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.
 			7:00	-	+07	1933 Jan  1
@@ -3334,7 +3348,7 @@
 # even worse.  For now, let's use a numeric abbreviation; we can
 # switch to "SLST" if it catches on.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Colombo	5:19:24 -	LMT	1880
 			5:19:32	-	MMT	1906        # Moratuwa Mean Time
 			5:30	-	+0530	1942 Jan  5
@@ -3504,13 +3518,13 @@
 Rule	Syria	2012	max	-	Mar	lastFri	0:00	1:00	S
 Rule	Syria	2009	max	-	Oct	lastFri	0:00	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Damascus	2:25:12 -	LMT	1920 # Dimashq
 			2:00	Syria	EE%sT
 
 # Tajikistan
 # From Shanks & Pottenger.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Dushanbe	4:35:12 -	LMT	1924 May  2
 			5:00	-	+05	1930 Jun 21
 			6:00 RussiaAsia +06/+07	1991 Mar 31  2:00s
@@ -3518,7 +3532,7 @@
 			5:00	-	+05
 
 # Thailand
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Bangkok	6:42:04	-	LMT	1880
 			6:42:04	-	BMT	1920 Apr # Bangkok Mean Time
 			7:00	-	+07
@@ -3527,7 +3541,7 @@
 
 # Turkmenistan
 # From Shanks & Pottenger.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Ashgabat	3:53:32 -	LMT	1924 May  2 # or Ashkhabad
 			4:00	-	+04	1930 Jun 21
 			5:00 RussiaAsia	+05/+06	1991 Mar 31  2:00
@@ -3535,7 +3549,7 @@
 			5:00	-	+05
 
 # United Arab Emirates
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Dubai	3:41:12 -	LMT	1920
 			4:00	-	+04
 Link Asia/Dubai Asia/Muscat	# Oman
@@ -3542,7 +3556,7 @@
 
 # Uzbekistan
 # Byalokoz 1919 says Uzbekistan was 4:27:53.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Samarkand	4:27:53 -	LMT	1924 May  2
 			4:00	-	+04	1930 Jun 21
 			5:00	-	+05	1981 Apr  1
@@ -3608,7 +3622,7 @@
 # Lê Thành Lân: "Lịch hai thế kỷ (1802-2010) và các lịch vĩnh cửu",
 # NXB Thuận Hoá, Huế, 1995.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Asia/Ho_Chi_Minh	7:06:40 -	LMT	1906 Jul  1
 			7:06:30	-	PLMT	1911 May  1 # Phù Liễn MT
 			7:00	-	+07	1942 Dec 31 23:00
--- contrib/tzdata/australasia.orig
+++ contrib/tzdata/australasia
@@ -25,7 +25,7 @@
 # says W Australia didn't use DST in 1943/1944.  Ignore Whitman's claim that
 # 1944/1945 was just like 1943/1944.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # Northern Territory
 Zone Australia/Darwin	 8:43:20 -	LMT	1895 Feb
 			 9:00	-	ACST	1899 May
@@ -102,7 +102,7 @@
 Rule	AS	2007	only	-	Mar	lastSun	2:00s	0	S
 Rule	AS	2008	max	-	Apr	Sun>=1	2:00s	0	S
 Rule	AS	2008	max	-	Oct	Sun>=1	2:00s	1:00	D
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Australia/Adelaide	9:14:20 -	LMT	1895 Feb
 			9:00	-	ACST	1899 May
 			9:30	Aus	AC%sT	1971
@@ -134,7 +134,7 @@
 Rule	AT	2006	only	-	Apr	Sun>=1	2:00s	0	S
 Rule	AT	2007	only	-	Mar	lastSun	2:00s	0	S
 Rule	AT	2008	max	-	Apr	Sun>=1	2:00s	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Australia/Hobart	9:49:16	-	LMT	1895 Sep
 			10:00	-	AEST	1916 Oct  1  2:00
 			10:00	1:00	AEDT	1917 Feb
@@ -162,7 +162,7 @@
 Rule	AV	2007	only	-	Mar	lastSun	2:00s	0	S
 Rule	AV	2008	max	-	Apr	Sun>=1	2:00s	0	S
 Rule	AV	2008	max	-	Oct	Sun>=1	2:00s	1:00	D
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Australia/Melbourne 9:39:52 -	LMT	1895 Feb
 			10:00	Aus	AE%sT	1971
 			10:00	AV	AE%sT
@@ -185,7 +185,7 @@
 Rule	AN	2007	only	-	Mar	lastSun	2:00s	0	S
 Rule	AN	2008	max	-	Apr	Sun>=1	2:00s	0	S
 Rule	AN	2008	max	-	Oct	Sun>=1	2:00s	1:00	D
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Australia/Sydney	10:04:52 -	LMT	1895 Feb
 			10:00	Aus	AE%sT	1971
 			10:00	AN	AE%sT
@@ -256,7 +256,7 @@
 			11:00	-	+11
 
 # Christmas
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Indian/Christmas	7:02:52 -	LMT	1895 Feb
 			7:00	-	+07
 
@@ -263,7 +263,7 @@
 # Cocos (Keeling) Is
 # These islands were ruled by the Ross family from about 1830 to 1978.
 # We don't know when standard time was introduced; for now, we guess 1900.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Indian/Cocos	6:27:40	-	LMT	1900
 			6:30	-	+0630
 
@@ -386,12 +386,12 @@
 Rule	Fiji	2014	only	-	Jan	Sun>=18	2:00	0	-
 Rule	Fiji	2014	max	-	Nov	Sun>=1	2:00	1:00	-
 Rule	Fiji	2015	max	-	Jan	Sun>=13	3:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Fiji	11:55:44 -	LMT	1915 Oct 26 # Suva
 			12:00	Fiji	+12/+13
 
 # French Polynesia
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Gambier	 -8:59:48 -	LMT	1912 Oct # Rikitea
 			 -9:00	-	-09
 Zone	Pacific/Marquesas -9:18:00 -	LMT	1912 Oct
@@ -434,7 +434,7 @@
 # http://documents.guam.gov/wp-content/uploads/E.O.-77-18-Guam-Standard-Time.pdf
 Rule	Guam	1977	only	-	Aug	28	2:00	0	S
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Guam	-14:21:00 -	LMT	1844 Dec 31
 			 9:39:00 -	LMT	1901        # Agana
 			10:00	-	GST	1941 Dec 10 # Guam
@@ -444,7 +444,7 @@
 Link Pacific/Guam Pacific/Saipan # N Mariana Is
 
 # Kiribati
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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
@@ -460,7 +460,7 @@
 # See Pacific/Guam.
 
 # Marshall Is
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Majuro	 11:24:48 -	LMT	1901
 			 11:00	-	+11	1914 Oct
 			  9:00	-	+09	1919 Feb  1
@@ -478,7 +478,7 @@
 			 12:00	-	+12
 
 # Micronesia
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Chuuk	-13:52:52 -	LMT	1844 Dec 31
 			 10:07:08 -	LMT	1901
 			 10:00	-	+10	1914 Oct
@@ -506,7 +506,7 @@
 			 11:00	-	+11
 
 # Nauru
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Nauru	11:07:40 -	LMT	1921 Jan 15 # Uaobe
 			11:30	-	+1130	1942 Aug 29
 			 9:00	-	+09	1945 Sep  8
@@ -520,7 +520,7 @@
 Rule	NC	1996	only	-	Dec	 1	2:00s	1:00	-
 # Shanks & Pottenger say the following was at 2:00; go with IATA.
 Rule	NC	1997	only	-	Mar	 2	2:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Noumea	11:05:48 -	LMT	1912 Jan 13 # Nouméa
 			11:00	NC	+11/+12
 
@@ -559,7 +559,7 @@
 Rule	Chatham	2007	max	-	Sep	lastSun	2:45s	1:00	-
 Rule	NZ	2008	max	-	Apr	Sun>=1	2:00s	0	S
 Rule	Chatham	2008	max	-	Apr	Sun>=1	2:45s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Auckland	11:39:04 -	LMT	1868 Nov  2
 			11:30	NZ	NZ%sT	1946 Jan  1
 			12:00	NZ	NZ%sT
@@ -585,7 +585,7 @@
 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		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Rarotonga	-10:39:04 -	LMT	1901        # Avarua
 			-10:30	-	-1030	1978 Nov 12
 			-10:00	Cook	-10/-0930
@@ -594,7 +594,7 @@
 
 
 # Niue
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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
@@ -601,7 +601,7 @@
 			-11:00	-	-11
 
 # Norfolk
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Norfolk	11:11:52 -	LMT	1901 # Kingston
 			11:12	-	+1112	1951
 			11:30	-	+1130	1974 Oct 27 02:00
@@ -610,13 +610,13 @@
 			11:00	-	+11
 
 # Palau (Belau)
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Palau	-15:02:04 -	LMT	1844 Dec 31	# Koror
 			  8:57:56 -	LMT	1901
 			  9:00	-	+09
 
 # Papua New Guinea
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Port_Moresby 9:48:40 -	LMT	1880
 			9:48:32	-	PMMT	1895 # Port Moresby Mean Time
 			10:00	-	+10
@@ -646,7 +646,7 @@
 			11:00	-	+11
 
 # Pitcairn
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Pitcairn	-8:40:20 -	LMT	1901        # Adamstown
 			-8:30	-	-0830	1998 Apr 27  0:00
 			-8:00	-	-08
@@ -731,7 +731,7 @@
 Rule	WS	2011	only	-	Sep	lastSat	3:00	1	-
 Rule	WS	2012	max	-	Apr	Sun>=1	4:00	0	-
 Rule	WS	2012	max	-	Sep	lastSun	3:00	1	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Apia	 12:33:04 -	LMT	1892 Jul  5
 			-11:26:56 -	LMT	1911
 			-11:30	-	-1130	1950
@@ -740,7 +740,7 @@
 
 # Solomon Is
 # excludes Bougainville, for which see Papua New Guinea
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Guadalcanal 10:39:48 -	LMT	1912 Oct # Honiara
 			11:00	-	+11
 
@@ -763,7 +763,7 @@
 # was "11 hours slow on G.M.T."  Go with Thorsen and assume Shanks & Pottenger
 # are off by an hour starting in 1901.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Fakaofo	-11:24:56 -	LMT	1901
 			-11:00	-	-11	2011 Dec 30
 			13:00	-	+13
@@ -776,7 +776,7 @@
 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		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Tongatapu	12:19:20 -	LMT	1901
 			12:20	-	+1220	1941
 			13:00	-	+13	1999
@@ -783,7 +783,7 @@
 			13:00	Tonga	+13/+14
 
 # Tuvalu
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Funafuti	11:56:52 -	LMT	1901
 			12:00	-	+12
 
@@ -844,7 +844,7 @@
 # uninhabited since World War II; was probably like Pacific/Kiritimati
 
 # Wake
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Wake	11:06:28 -	LMT	1901
 			12:00	-	+12
 
@@ -857,12 +857,12 @@
 Rule	Vanuatu	1985	1991	-	Sep	Sun>=23	0:00	1:00	-
 Rule	Vanuatu	1992	1993	-	Jan	Sun>=23	0:00	0	-
 Rule	Vanuatu	1992	only	-	Oct	Sun>=23	0:00	1:00	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Efate	11:13:16 -	LMT	1912 Jan 13 # Vila
 			11:00	Vanuatu	+11/+12
 
 # Wallis and Futuna
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 			12:00	-	+12
 
@@ -1248,6 +1248,22 @@
 # in WA or its introduction in SA had anything to do with the genesis
 # of this time zone.  My hunch is that it's been around since well
 # before 1975.  I remember seeing it noted on road maps decades ago.
+#
+# From Gilmore Davidson (2019-04-08):
+# https://www.abc.net.au/news/2019-04-08/this-remote-stretch-of-desert-has-its-own-custom-time-zone/10981000
+# ... include[s] a rough description of the geographical boundaries...
+# "The time zone exists for about 340 kilometres and takes in the tiny
+# roadhouse communities of Cocklebiddy, Madura, Eucla and Border Village."
+# ... and an indication that the zone has definitely been in existence
+# since before the 1970 cut-off of the database ...
+# From Paul Eggert (2019-05-17):
+# That ABC Esperance story by Christien de Garis also says:
+#    Although the Central Western Time Zone is not officially recognised (your
+#    phones won't automatically change), there is a sign instructing you which
+#    way to wind your clocks 45 minutes and scrawled underneath one of them in
+#    Texta is the word: 'Why'?
+#    "Good question," Mr Pike said.
+#    "I don't even know that, and it's been going for over 50 years."
 
 # From Paul Eggert (2006-12-15):
 # For lack of better info, assume the tradition dates back to the
@@ -1566,6 +1582,42 @@
 ###############################################################################
 
 
+# Bonin (Ogasawara) Islands and Marcus Island (Minami-Tori-shima)
+
+# From Wakaba (2019-01-28) via Phake Nick:
+# National Diet Library of Japan has several reports by Japanese Government
+# officers that describe the time used in islands when they visited there.
+# According to them (and other sources such as newspapers), standard time UTC
+# + 10 (JST + 1) and DST UTC + 11 (JST + 2) was used until its return to Japan
+# at 1968-06-26 00:00 JST.  The exact periods of DST are still unknown.
+# I guessed Guam, Mariana, and Bonin and Marcus districts might have
+# synchronized their DST periods, but reports imply they had their own
+# decisions, i.e. there were three or more different time zones....
+#
+# https://wiki.suikawiki.org/n/小笠原諸島の標準時
+
+# From Phake Nick (2019-02-12):
+# Because their last time change to return to Japanese time when they returned
+# to Japanese rule was right before 1970, ... per the current tz database
+# rule, the information doesn't warrant creation of a new timezone for Bonin
+# Islands itself and is thus as an anecdotal note for interest purpose only.
+# ... [The abovementioned link] described some special timekeeping phenomenon
+# regarding Marcus island, another remote island currently owned by Japanese
+# in the same administrative unit as Bonin Islands.  Many reports claim that
+# the American coastal guard on the American quarter of the island use its own
+# coastal guard time, and most sources describe the time as UTC+11, being two
+# hours faster than JST used by some Japanese personnel on the island.  Some
+# sites describe it as same as Wake Island/Guam time although it would be
+# incorrect to be same as Guam.  And then in a few Japanese governmental
+# report from 1980s (from National Institute of Information and Communications
+# Technology) regarding the construction of VLBI facility on the Marcus
+# Island, it claimed that there are three time standards being used on the
+# island at the time which include not just JST (UTC+9) or [US]CG time
+# (UTC+11) but also a JMSDF time (UTC+10) (Japan Maritime Self-Defense
+# Force).  Unfortunately there are no other sources that mentioned such time
+# and there are also no information on things like how the time was used.
+
+
 # Fiji
 
 # Howse writes (p 153) that in 1879 the British governor of Fiji
--- contrib/tzdata/backzone.orig
+++ contrib/tzdata/backzone
@@ -38,7 +38,7 @@
 # commentary and rules associated with the entry.
 #
 # As explained in the zic man page, the zone columns are:
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 
 # Ethiopia
 # From Paul Eggert (2014-07-31):
--- contrib/tzdata/checktab.awk.orig
+++ contrib/tzdata/checktab.awk
@@ -63,12 +63,19 @@
 		coordinates = $2
 		tz = $3
 		comments = $4
-		if (cc < cc0) {
+
+		# Don't complain about a special case for Crimea in zone.tab.
+		# FIXME: zone.tab should be removed, since it is obsolete.
+		# Or at least put just "XX" in its country-code column.
+		if (cc < cc0 \
+		    && !(zone_table == "zone.tab" \
+			 && tz0 == "Europe/Simferopol")) {
 			printf "%s:%d: country code '%s' is out of order\n", \
 				zone_table, zone_NR, cc >>"/dev/stderr"
 			status = 1
 		}
 		cc0 = cc
+		tz0 = tz
 		tztab[tz] = 1
 		tz2comments[tz] = comments
 		tz2NR[tz] = zone_NR
--- contrib/tzdata/europe.orig
+++ contrib/tzdata/europe
@@ -122,7 +122,7 @@
 # position is 51° 28' 30" N, 0° 18' 45" W. The longitude should
 # be within about ±2". The Ordnance Survey grid reference is TQ172761.
 #
-# [This yields GMTOFF = -0:01:15 for London LMT in the 18th century.]
+# [This yields STDOFF = -0:01:15 for London LMT in the 18th century.]
 
 # From Paul Eggert (1993-11-18):
 #
@@ -500,7 +500,7 @@
 #
 # Use Europe/London for Jersey, Guernsey, and the Isle of Man.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/London	-0:01:15 -	LMT	1847 Dec  1  0:00s
 			 0:00	GB-Eire	%s	1968 Oct 27
 			 1:00	-	BST	1971 Oct 31  2:00u
@@ -538,7 +538,7 @@
 Rule	Eire	1990	1995	-	Oct	Sun>=22	 1:00u	-1:00	-
 Rule	Eire	1996	max	-	Oct	lastSun	 1:00u	-1:00	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Dublin	-0:25:00 -	LMT	1880 Aug  2
 			-0:25:21 -	DMT	1916 May 21  2:00s
 			-0:25:21 1:00	IST	1916 Oct  1  2:00s
@@ -737,7 +737,7 @@
 
 # These are for backward compatibility with older versions.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	WET		0:00	EU	WE%sT
 Zone	CET		1:00	C-Eur	CE%sT
 Zone	MET		1:00	C-Eur	ME%sT
@@ -797,7 +797,7 @@
 Rule	Albania	1983	only	-	Apr	18	0:00	1:00	S
 Rule	Albania	1983	only	-	Oct	 1	0:00	0	-
 Rule	Albania	1984	only	-	Apr	 1	0:00	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Tirane	1:19:20 -	LMT	1914
 			1:00	-	CET	1940 Jun 16
 			1:00	Albania	CE%sT	1984 Jul
@@ -804,7 +804,7 @@
 			1:00	EU	CE%sT
 
 # Andorra
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Andorra	0:06:04 -	LMT	1901
 			0:00	-	WET	1946 Sep 30
 			1:00	-	CET	1985 Mar 31  2:00
@@ -830,7 +830,7 @@
 Rule	Austria	1948	only	-	Apr	18	2:00s	1:00	S
 Rule	Austria	1980	only	-	Apr	 6	0:00	1:00	S
 Rule	Austria	1980	only	-	Sep	28	0:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Vienna	1:05:21 -	LMT	1893 Apr
 			1:00	C-Eur	CE%sT	1920
 			1:00	Austria	CE%sT	1940 Apr  1  2:00s
@@ -862,7 +862,7 @@
 # Belarussian government decided against changing to winter time....
 # http://eng.belta.by/all_news/society/Belarus-decides-against-adjusting-time-in-Russias-wake_i_76335.html
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Minsk	1:50:16 -	LMT	1880
 			1:50	-	MMT	1924 May  2 # Minsk Mean Time
 			2:00	-	EET	1930 Jun 21
@@ -926,7 +926,7 @@
 Rule	Belgium	1945	only	-	Sep	16	 2:00s	0	-
 Rule	Belgium	1946	only	-	May	19	 2:00s	1:00	S
 Rule	Belgium	1946	only	-	Oct	 7	 2:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Brussels	0:17:30 -	LMT	1880
 			0:17:30	-	BMT	1892 May  1 12:00  # Brussels MT
 			0:00	-	WET	1914 Nov  8
@@ -953,7 +953,7 @@
 Rule	Bulg	1980	1982	-	Apr	Sat>=1	23:00	1:00	S
 Rule	Bulg	1980	only	-	Sep	29	 1:00	0	-
 Rule	Bulg	1981	only	-	Sep	27	 2:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Sofia	1:33:16 -	LMT	1880
 			1:56:56	-	IMT	1894 Nov 30 # Istanbul MT?
 			2:00	-	EET	1942 Nov  2  3:00
@@ -986,7 +986,7 @@
 Rule	Czech	1946	1949	-	Oct	Sun>=1	2:00s	0	-
 Rule	Czech	1947	1948	-	Apr	Sun>=15	2:00s	1:00	S
 Rule	Czech	1949	only	-	Apr	 9	2:00s	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Prague	0:57:44 -	LMT	1850
 			0:57:44	-	PMT	1891 Oct    # Prague Mean Time
 			1:00	C-Eur	CE%sT	1945 May  9
@@ -1048,7 +1048,7 @@
 Rule	Denmark	1948	only	-	May	 9	 2:00s	1:00	S
 Rule	Denmark	1948	only	-	Aug	 8	 2:00s	0	-
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Europe/Copenhagen	 0:50:20 -	LMT	1890
 			 0:50:20 -	CMT	1894 Jan  1 # Copenhagen MT
 			 1:00	Denmark	CE%sT	1942 Nov  2  2:00s
@@ -1145,7 +1145,7 @@
 Rule	Thule	2007	max	-	Mar	Sun>=8	2:00	1:00	D
 Rule	Thule	2007	max	-	Nov	Sun>=1	2:00	0	S
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Danmarkshavn -1:14:40 -	LMT	1916 Jul 28
 			-3:00	-	-03	1980 Apr  6  2:00
 			-3:00	EU	-03/-02	1996
@@ -1211,7 +1211,7 @@
 # From Urmet Jänes (2002-03-28):
 # The legislative reference is Government decree No. 84 on 2002-02-21.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Tallinn	1:39:00	-	LMT	1880
 			1:39:00	-	TMT	1918 Feb    # Tallinn Mean Time
 			1:00	C-Eur	CE%sT	1919 Jul
@@ -1274,7 +1274,7 @@
 # Milne says Helsinki (Helsingfors) time was 1:39:49.2 (official document);
 # round to nearest.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 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
@@ -1364,7 +1364,7 @@
 # but Howse quotes the actual French legislation as saying 0:09:21.
 # Go with Howse.  Howse writes that the time in France was officially based
 # on PMT-0:09:21 until 1978-08-09, when the time base finally switched to UTC.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Paris	0:09:21 -	LMT	1891 Mar 15  0:01
 			0:09:21	-	PMT	1911 Mar 11  0:01 # Paris MT
 # Shanks & Pottenger give 1940 Jun 14 0:00; go with Excoffier and Le Corre.
@@ -1412,7 +1412,7 @@
 Rule SovietZone	1945	only	-	Sep	24	3:00	1:00	S
 Rule SovietZone	1945	only	-	Nov	18	2:00s	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Berlin	0:53:28 -	LMT	1893 Apr
 			1:00	C-Eur	CE%sT	1945 May 24  2:00
 			1:00 SovietZone	CE%sT	1946
@@ -1440,7 +1440,7 @@
 # is in Europe.  Our reference location Tbilisi is in the Asian part.
 
 # Gibraltar
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Europe/Gibraltar	-0:21:24 -	LMT	1880 Aug  2  0:00s
 			0:00	GB-Eire	%s	1957 Apr 14  2:00
 			1:00	-	CET	1982
@@ -1471,7 +1471,7 @@
 Rule	Greece	1979	only	-	Sep	29	2:00	0	-
 Rule	Greece	1980	only	-	Apr	 1	0:00	1:00	S
 Rule	Greece	1980	only	-	Sep	28	0:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Athens	1:34:52 -	LMT	1895 Sep 14
 			1:34:52	-	AMT	1916 Jul 28  0:01 # Athens MT
 			2:00	Greece	EE%sT	1941 Apr 30
@@ -1508,7 +1508,7 @@
 Rule	Hungary	1957	only	-	Jun	Sun>=1	 1:00	1:00	S
 Rule	Hungary	1957	only	-	Sep	lastSun	 3:00	0	-
 Rule	Hungary	1980	only	-	Apr	 6	 1:00	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Budapest	1:16:20 -	LMT	1890 Oct
 			1:00	C-Eur	CE%sT	1918
 			1:00	Hungary	CE%sT	1941 Apr  8
@@ -1569,7 +1569,7 @@
 Rule	Iceland	1949	only	-	Oct	30	 1:00s	0	-
 Rule	Iceland	1950	1966	-	Oct	Sun>=22	 1:00s	0	-
 Rule	Iceland	1967	only	-	Oct	29	 1:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Atlantic/Reykjavik	-1:28	-	LMT	1908
 			-1:00	Iceland	-01/+00	1968 Apr  7  1:00s
 			 0:00	-	GMT
@@ -1583,6 +1583,25 @@
 # But these events all occurred before the 1970 cutoff,
 # so record only the time in Rome.
 #
+# From Stephen Trainor (2019-05-06):
+# http://www.ac-ilsestante.it/MERIDIANE/ora_legale/ORA_LEGALE_ESTIVA_IN_ITALIA.htm
+# ... the [1866] law went into effect on 12 December 1866, rather than
+# the date of the decree (22 Sep 1866)
+# https://web.archive.org/web/20070824155341/http://www.iav.it/planetario/didastro/didastro/english.htm
+# ... "In Italy in 1866 there were 6 railway times (Torino, Verona, Firenze,
+# Roma, Napoli, Palermo). On that year it was decided to unify them, adopting
+# the average time of Rome (even if this city was not yet part of the
+# kingdom).  On the 12th December 1866, on the starting of the winter time
+# table, it took effect in the railways, the post office and the telegraph,
+# not only for the internal service but also for the public....  Milano set
+# the public watches on the Rome time on the same day (12th December 1866),
+# Torino and Bologna on the 1st January 1867, Venezia the 1st May 1880 and the
+# last city was Cagliari in 1886."
+#
+# From Luigi Rosa (2019-05-07):
+# this is the scan of the decree:
+# http://www.radiomarconi.com/marconi/filopanti/1866c.jpg
+#
 # From Michael Deckers (2016-10-24):
 # http://www.ac-ilsestante.it/MERIDIANE/ora_legale quotes a law of 1893-08-10
 # ... [translated as] "The preceding dispositions will enter into
@@ -1593,6 +1612,7 @@
 # The authoritative source for time in Italy is the national metrological
 # institute, which has a summary page of historical DST data at
 # http://www.inrim.it/res/tf/ora_legale_i.shtml
+# [now at http://oldsite.inrim.it/res/tf/ora_legale_i.shtml as of 2017]
 # (2016-10-24):
 # http://www.renzobaldini.it/le-ore-legali-in-italia/
 # has still different data for 1944.  It divides Italy in two, as
@@ -1656,8 +1676,8 @@
 Rule	Italy	1977	1979	-	May	Sun>=22	 0:00s	1:00	S
 Rule	Italy	1978	only	-	Oct	 1	 0:00s	0	-
 Rule	Italy	1979	only	-	Sep	30	 0:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
-Zone	Europe/Rome	0:49:56 -	LMT	1866 Sep 22
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
+Zone	Europe/Rome	0:49:56 -	LMT	1866 Dec 12
 			0:49:56	-	RMT	1893 Oct 31 23:49:56 # Rome Mean
 			1:00	Italy	CE%sT	1943 Sep 10
 			1:00	C-Eur	CE%sT	1944 Jun  4
@@ -1732,7 +1752,7 @@
 # Byalokoz 1919 says Latvia was 1:36:34.
 # Go with Byalokoz.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Riga	1:36:34	-	LMT	1880
 			1:36:34	-	RMT	1918 Apr 15  2:00 # Riga MT
 			1:36:34	1:00	LST	1918 Sep 16  3:00 # Latvian ST
@@ -1802,7 +1822,7 @@
 # http://www.lrvk.lt/nut/11/n1749.htm
 
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Vilnius	1:41:16	-	LMT	1880
 			1:24:00	-	WMT	1917        # Warsaw Mean Time
 			1:35:36	-	KMT	1919 Oct 10 # Kaunas Mean Time
@@ -1846,7 +1866,7 @@
 Rule	Lux	1927	only	-	Apr	 9	23:00	1:00	S
 Rule	Lux	1928	only	-	Apr	14	23:00	1:00	S
 Rule	Lux	1929	only	-	Apr	20	23:00	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Europe/Luxembourg	0:24:36 -	LMT	1904 Jun
 			1:00	Lux	CE%sT	1918 Nov 25
 			0:00	Lux	WE%sT	1929 Oct  6  2:00s
@@ -1871,7 +1891,7 @@
 Rule	Malta	1975	1979	-	Apr	Sun>=15	2:00	1:00	S
 Rule	Malta	1975	1980	-	Sep	Sun>=15	2:00	0	-
 Rule	Malta	1980	only	-	Mar	31	2:00	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Malta	0:58:04 -	LMT	1893 Nov  2  0:00s # Valletta
 			1:00	Italy	CE%sT	1973 Mar 31
 			1:00	Malta	CE%sT	1981
@@ -1940,7 +1960,7 @@
 Rule	Moldova	1997	max	-	Mar	lastSun	 2:00	1:00	S
 Rule	Moldova	1997	max	-	Oct	lastSun	 3:00	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Chisinau	1:55:20 -	LMT	1880
 			1:55	-	CMT	1918 Feb 15 # Chisinau MT
 			1:44:24	-	BMT	1931 Jul 24 # Bucharest MT
@@ -1956,7 +1976,7 @@
 # Monaco
 # Shanks & Pottenger give 0:09:20 for Paris Mean Time; go with Howse's
 # more precise 0:09:21.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Monaco	0:29:32 -	LMT	1891 Mar 15
 			0:09:21	-	PMT	1911 Mar 11 # Paris Mean Time
 			0:00	France	WE%sT	1945 Sep 16  3:00
@@ -2031,8 +2051,8 @@
 Rule	Neth	1945	only	-	Sep	16	2:00s	0	-
 #
 # Amsterdam Mean Time was +00:19:32.13, but the .13 is omitted
-# below because the current format requires GMTOFF to be an integer.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# below because the current format requires STDOFF to be an integer.
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Europe/Amsterdam	0:19:32 -	LMT	1835
 			0:19:32	Neth	%s	1937 Jul  1
 			0:20	Neth +0020/+0120 1940 May 16  0:00
@@ -2051,7 +2071,7 @@
 Rule	Norway	1959	1964	-	Mar	Sun>=15	2:00s	1:00	S
 Rule	Norway	1959	1965	-	Sep	Sun>=15	2:00s	0	-
 Rule	Norway	1965	only	-	Apr	25	2:00s	1:00	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Oslo	0:43:00 -	LMT	1895 Jan  1
 			1:00	Norway	CE%sT	1940 Aug 10 23:00
 			1:00	C-Eur	CE%sT	1945 Apr  2  2:00
@@ -2142,7 +2162,7 @@
 Rule	Poland	1960	only	-	Apr	 3	1:00s	1:00	S
 Rule	Poland	1961	1964	-	May	lastSun	1:00s	1:00	S
 Rule	Poland	1962	1964	-	Sep	lastSun	1:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Warsaw	1:24:00 -	LMT	1880
 			1:24:00	-	WMT	1915 Aug  5 # Warsaw Mean Time
 			1:00	C-Eur	CE%sT	1918 Sep 16  3:00
@@ -2247,7 +2267,7 @@
 Rule	Port	1981	1982	-	Mar	lastSun	 1:00s	1:00	S
 Rule	Port	1983	only	-	Mar	lastSun	 2:00s	1:00	S
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Lisbon	-0:36:45 -	LMT	1884
 			-0:36:45 -	LMT	1912 Jan  1  0:00u # Lisbon MT
 			 0:00	Port	WE%sT	1966 Apr  3  2:00
@@ -2306,7 +2326,7 @@
 Rule	Romania	1980	only	-	Sep	lastSun	 1:00	0	-
 Rule	Romania	1991	1993	-	Mar	lastSun	 0:00s	1:00	S
 Rule	Romania	1991	1993	-	Sep	lastSun	 0:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Europe/Bucharest	1:44:24 -	LMT	1891 Oct
 			1:44:24	-	BMT	1931 Jul 24 # Bucharest MT
 			2:00	Romania	EE%sT	1981 Mar 29  2:00s
@@ -3345,7 +3365,7 @@
 # See Europe/Rome.
 
 # Serbia
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Belgrade	1:22:00	-	LMT	1884
 			1:00	-	CET	1941 Apr 18 23:00
 			1:00	C-Eur	CE%sT	1945
@@ -3451,7 +3471,7 @@
 Rule SpainAfrica 1977	only	-	Sep	28	 0:00	0	-
 Rule SpainAfrica 1978	only	-	Jun	 1	 0:00	1:00	S
 Rule SpainAfrica 1978	only	-	Aug	 4	 0:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Madrid	-0:14:44 -	LMT	1900 Dec 31 23:45:16
 			 0:00	Spain	WE%sT	1940 Mar 16 23:00
 			 1:00	Spain	CE%sT	1979
@@ -3519,7 +3539,7 @@
 #
 # Source: The newspaper "Dagens Nyheter", 1916-10-01, page 7 upper left.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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
 			1:00	-	CET	1916 May 14 23:00
@@ -3622,7 +3642,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Swiss	1941	1942	-	May	Mon>=1	1:00	1:00	S
 Rule	Swiss	1941	1942	-	Oct	Mon>=1	2:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Zurich	0:34:08 -	LMT	1853 Jul 16 # See above comment.
 			0:29:46	-	BMT	1894 Jun    # Bern Mean Time
 			1:00	Swiss	CE%sT	1981
@@ -3772,7 +3792,7 @@
 Rule	Turkey	1994	only	-	Mar	20	1:00s	1:00	S
 Rule	Turkey	1995	2006	-	Mar	lastSun	1:00s	1:00	S
 Rule	Turkey	1996	2006	-	Oct	lastSun	1:00s	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Europe/Istanbul	1:55:52 -	LMT	1880
 			1:56:56	-	IMT	1910 Oct # Istanbul Mean Time?
 			2:00	Turkey	EE%sT	1978 Oct 15
@@ -3869,16 +3889,8 @@
 # controversial, and some day "Kyiv" may become substantially more popular in
 # English; in the meantime, stick with the traditional English "Kiev" as that
 # means less disruption for our users.
-#
-# Anyway, none of the common English-language spellings (Kiev, Kyiv, Kieff,
-# Kijeff, Kijev, Kiyef, Kiyeff) do justice to the common pronunciation in
-# Ukrainian, namely [ˈkɪjiu̯] (IPA).  This pronunciation has nothing like an
-# English "v" or "f", and instead trails off with what an English-speaker
-# would call a demure "oo" sound, and it would would be better anglicized as
-# "Kuiyu".  Here's a sound file, if you would like to do as the Kuiyuvians do:
-# https://commons.wikimedia.org/wiki/File:Uk-Київ.ogg
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # This represents most of Ukraine.  See above for the spelling of "Kiev".
 Zone Europe/Kiev	2:02:04 -	LMT	1880
 			2:02:04	-	KMT	1924 May  2 # Kiev Mean Time
--- contrib/tzdata/factory.orig
+++ contrib/tzdata/factory
@@ -8,5 +8,5 @@
 # time zone abbreviation "-00", indicating that the actual time zone
 # is unknown.
 
-# Zone	NAME	GMTOFF	RULES	FORMAT
+# Zone	NAME	STDOFF	RULES	FORMAT
 Zone	Factory	0	- "Local time zone must be set--use tzsetup"
--- contrib/tzdata/northamerica.orig
+++ contrib/tzdata/northamerica
@@ -93,10 +93,33 @@
 # was the first nationwide legal time standard, and apparently
 # time was just called "Standard Time" or "Daylight Saving Time".
 
-# From Arthur David Olson:
-# US Daylight Saving Time ended on the last Sunday of *October* in 1974.
-# See, for example, the front page of the Saturday, 1974-10-26
-# and Sunday, 1974-10-27 editions of the Washington Post.
+# From Paul Eggert (2019-06-04):
+# Here is the legal basis for the US federal rules.
+# * Public Law 65-106 (1918-03-19) implemented standard and daylight saving
+#   time for the first time across the US, springing forward on March's last
+#   Sunday and falling back on October's last Sunday.
+#   https://www.loc.gov/law/help/statutes-at-large/65th-congress/session-2/c65s2ch24.pdf
+# * Public Law 66-40 (1919-08-20) repealed DST on October 1919's last Sunday.
+#   https://www.loc.gov/law/help/statutes-at-large/66th-congress/session-1/c66s1ch51.pdf
+# * Public Law 77-403 (1942-01-20) started wartime DST on 1942-02-09.
+#   https://www.loc.gov/law/help/statutes-at-large/77th-congress/session-2/c77s2ch7.pdf
+# * Public Law 79-187 (1945-09-25) ended wartime DST on 1945-09-30.
+#   https://www.loc.gov/law/help/statutes-at-large/79th-congress/session-1/c79s1ch388.pdf
+# * Public Law 89-387 (1966-04-13) reinstituted a national standard for DST,
+#   from April's last Sunday to October's last Sunday, effective 1967.
+#   https://www.govinfo.gov/content/pkg/STATUTE-80/pdf/STATUTE-80-Pg107.pdf
+# * Public Law 93-182 (1973-12-15) moved the 1974 spring-forward to 01-06.
+#   https://www.govinfo.gov/content/pkg/STATUTE-87/pdf/STATUTE-87-Pg707.pdf
+# * Public Law 93-434 (1974-10-05) moved the 1975 spring-forward to
+#   February's last Sunday.
+#   https://www.govinfo.gov/content/pkg/STATUTE-88/pdf/STATUTE-88-Pg1209.pdf
+# * Public Law 99-359 (1986-07-08) moved the spring-forward to April's first
+#   Sunday.
+#   https://www.govinfo.gov/content/pkg/STATUTE-100/pdf/STATUTE-100-Pg764.pdf
+# * Public Law 109-58 (2005-08-08), effective 2007, moved the spring-forward
+#   to March's second Sunday and the fall-back to November's first Sunday.
+#   https://www.govinfo.gov/content/pkg/PLAW-109publ58/pdf/PLAW-109publ58.pdf
+# All transitions are at 02:00 local time.
 
 # From Arthur David Olson:
 # Before the Uniform Time Act of 1966 took effect in 1967, observance of
@@ -152,11 +175,11 @@
 Rule	US	1918	1919	-	Oct	lastSun	2:00	0	S
 Rule	US	1942	only	-	Feb	9	2:00	1:00	W # War
 Rule	US	1945	only	-	Aug	14	23:00u	1:00	P # Peace
-Rule	US	1945	only	-	Sep	lastSun	2:00	0	S
+Rule	US	1945	only	-	Sep	30	2:00	0	S
 Rule	US	1967	2006	-	Oct	lastSun	2:00	0	S
 Rule	US	1967	1973	-	Apr	lastSun	2:00	1:00	D
 Rule	US	1974	only	-	Jan	6	2:00	1:00	D
-Rule	US	1975	only	-	Feb	23	2:00	1:00	D
+Rule	US	1975	only	-	Feb	lastSun	2:00	1:00	D
 Rule	US	1976	1986	-	Apr	lastSun	2:00	1:00	D
 Rule	US	1987	2006	-	Apr	Sun>=1	2:00	1:00	D
 Rule	US	2007	max	-	Mar	Sun>=8	2:00	1:00	D
@@ -173,7 +196,7 @@
 # increase the chances that they'll actually get compiled and to
 # avoid the need to duplicate the US rules in another file.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	EST		 -5:00	-	EST
 Zone	MST		 -7:00	-	MST
 Zone	HST		-10:00	-	HST
@@ -330,7 +353,7 @@
 Rule	NYC	1921	1966	-	Apr	lastSun	2:00	1:00	D
 Rule	NYC	1921	1954	-	Sep	lastSun	2:00	0	S
 Rule	NYC	1955	1966	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/New_York	-4:56:02 -	LMT	1883 Nov 18 12:03:58
 			-5:00	US	E%sT	1920
 			-5:00	NYC	E%sT	1942
@@ -390,7 +413,7 @@
 Rule	Chicago	1922	1966	-	Apr	lastSun	2:00	1:00	D
 Rule	Chicago	1922	1954	-	Sep	lastSun	2:00	0	S
 Rule	Chicago	1955	1966	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Chicago	-5:50:36 -	LMT	1883 Nov 18 12:09:24
 			-6:00	US	C%sT	1920
 			-6:00	Chicago	C%sT	1936 Mar  1  2:00
@@ -458,7 +481,7 @@
 Rule	Denver	1921	only	-	May	22	2:00	0	S
 Rule	Denver	1965	1966	-	Apr	lastSun	2:00	1:00	D
 Rule	Denver	1965	1966	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Denver	-6:59:56 -	LMT	1883 Nov 18 12:00:04
 			-7:00	US	M%sT	1920
 			-7:00	Denver	M%sT	1942
@@ -511,7 +534,7 @@
 Rule	CA	1950	1966	-	Apr	lastSun	1:00	1:00	D
 Rule	CA	1950	1961	-	Sep	lastSun	2:00	0	S
 Rule	CA	1962	1966	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Los_Angeles -7:52:58 -	LMT	1883 Nov 18 12:07:02
 			-8:00	US	P%sT	1946
 			-8:00	CA	P%sT	1967
@@ -619,7 +642,7 @@
 # So they won't be waiting for Alaska to join them on 2019-03-10, but will
 # rather change their clocks twice in seven weeks.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Juneau	 15:02:19 -	LMT	1867 Oct 19 15:33:32
 			 -8:57:41 -	LMT	1900 Aug 20 12:00
 			 -8:00	-	PST	1942
@@ -739,7 +762,7 @@
 # Note that 1933-05-21 was a Sunday.
 # We're left to guess the time of day when Act 163 was approved; guess noon.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Honolulu	-10:31:26 -	LMT	1896 Jan 13 12:00
 			-10:30	-	HST	1933 Apr 30  2:00
 			-10:30	1:00	HDT	1933 May 21 12:00
@@ -769,7 +792,7 @@
 # Shanks says the 1944 experiment came to an end on 1944-03-17.
 # Go with the Arizona State Library instead.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Phoenix	-7:28:18 -	LMT	1883 Nov 18 11:31:42
 			-7:00	US	M%sT	1944 Jan  1  0:01
 			-7:00	-	MST	1944 Apr  1  0:01
@@ -795,7 +818,7 @@
 # quarter of Idaho county) and eastern Oregon (most of Malheur County)
 # switched four weeks late in 1974.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Boise	-7:44:49 -	LMT	1883 Nov 18 12:15:11
 			-8:00	US	P%sT	1923 May 13  2:00
 			-7:00	US	M%sT	1974
@@ -867,7 +890,7 @@
 Rule Indianapolis 1941	only	-	Jun	22	2:00	1:00	D
 Rule Indianapolis 1941	1954	-	Sep	lastSun	2:00	0	S
 Rule Indianapolis 1946	1954	-	Apr	lastSun	2:00	1:00	D
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Indianapolis -5:44:38 - LMT	1883 Nov 18 12:15:22
 			-6:00	US	C%sT	1920
 			-6:00 Indianapolis C%sT	1942
@@ -887,7 +910,7 @@
 Rule	Marengo	1951	only	-	Sep	lastSun	2:00	0	S
 Rule	Marengo	1954	1960	-	Apr	lastSun	2:00	1:00	D
 Rule	Marengo	1954	1960	-	Sep	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Marengo -5:45:23 -	LMT	1883 Nov 18 12:14:37
 			-6:00	US	C%sT	1951
 			-6:00	Marengo	C%sT	1961 Apr 30  2:00
@@ -911,7 +934,7 @@
 Rule Vincennes	1960	only	-	Oct	lastSun	2:00	0	S
 Rule Vincennes	1961	only	-	Sep	lastSun	2:00	0	S
 Rule Vincennes	1962	1963	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Vincennes -5:50:07 - LMT	1883 Nov 18 12:09:53
 			-6:00	US	C%sT	1946
 			-6:00 Vincennes	C%sT	1964 Apr 26  2:00
@@ -932,7 +955,7 @@
 Rule Perry	1960	only	-	Oct	lastSun	2:00	0	S
 Rule Perry	1961	only	-	Sep	lastSun	2:00	0	S
 Rule Perry	1962	1963	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Tell_City -5:47:03 - LMT	1883 Nov 18 12:12:57
 			-6:00	US	C%sT	1946
 			-6:00 Perry	C%sT	1964 Apr 26  2:00
@@ -948,7 +971,7 @@
 Rule	Pike	1955	1960	-	Sep	lastSun	2:00	0	S
 Rule	Pike	1956	1964	-	Apr	lastSun	2:00	1:00	D
 Rule	Pike	1961	1964	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Petersburg -5:49:07 - LMT	1883 Nov 18 12:10:53
 			-6:00	US	C%sT	1955
 			-6:00	Pike	C%sT	1965 Apr 25  2:00
@@ -970,7 +993,7 @@
 Rule	Starke	1955	1956	-	Oct	lastSun	2:00	0	S
 Rule	Starke	1957	1958	-	Sep	lastSun	2:00	0	S
 Rule	Starke	1959	1961	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Knox -5:46:30 -	LMT	1883 Nov 18 12:13:30
 			-6:00	US	C%sT	1947
 			-6:00	Starke	C%sT	1962 Apr 29  2:00
@@ -986,7 +1009,7 @@
 Rule	Pulaski	1946	1954	-	Sep	lastSun	2:00	0	S
 Rule	Pulaski	1955	1956	-	Oct	lastSun	2:00	0	S
 Rule	Pulaski	1957	1960	-	Sep	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Winamac -5:46:25 - LMT	1883 Nov 18 12:13:35
 			-6:00	US	C%sT	1946
 			-6:00	Pulaski	C%sT	1961 Apr 30  2:00
@@ -997,7 +1020,7 @@
 			-5:00	US	E%sT
 #
 # Switzerland County, Indiana, did not observe DST from 1973 through 2005.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Indiana/Vevay -5:40:16 -	LMT	1883 Nov 18 12:19:44
 			-6:00	US	C%sT	1954 Apr 25  2:00
 			-5:00	-	EST	1969
@@ -1022,7 +1045,7 @@
 Rule Louisville	1946	only	-	Jun	2	2:00	0	S
 Rule Louisville	1950	1955	-	Sep	lastSun	2:00	0	S
 Rule Louisville	1956	1960	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Kentucky/Louisville -5:43:02 -	LMT	1883 Nov 18 12:16:58
 			-6:00	US	C%sT	1921
 			-6:00 Louisville C%sT	1942
@@ -1128,7 +1151,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
 Rule	Detroit	1948	only	-	Apr	lastSun	2:00	1:00	D
 Rule	Detroit	1948	only	-	Sep	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Detroit	-5:32:11 -	LMT	1905
 			-6:00	-	CST	1915 May 15  2:00
 			-5:00	-	EST	1942
@@ -1145,7 +1168,7 @@
 Rule Menominee	1946	only	-	Sep	lastSun	2:00	0	S
 Rule Menominee	1966	only	-	Apr	lastSun	2:00	1:00	D
 Rule Menominee	1966	only	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Menominee	-5:50:27 -	LMT	1885 Sep 18 12:00
 			-6:00	US	C%sT	1946
 			-6:00 Menominee	C%sT	1969 Apr 27  2:00
@@ -1379,7 +1402,7 @@
 Rule	StJohns	2007	2010	-	Nov	Sun>=1	0:01	0	S
 #
 # St John's has an apostrophe, but Posix file names can't have apostrophes.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/St_Johns	-3:30:52 -	LMT	1884
 			-3:30:52 StJohns N%sT	1918
 			-3:30:52 Canada	N%sT	1919
@@ -1392,7 +1415,7 @@
 # most of east Labrador
 
 # The name 'Happy Valley-Goose Bay' is too long; use 'Goose Bay'.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Goose_Bay	-4:01:40 -	LMT	1884 # Happy Valley-Goose Bay
 			-3:30:52 -	NST	1918
 			-3:30:52 Canada N%sT	1919
@@ -1466,7 +1489,7 @@
 Rule	Halifax	1956	1959	-	Sep	lastSun	2:00	0	S
 Rule	Halifax	1962	1973	-	Apr	lastSun	2:00	1:00	D
 Rule	Halifax	1962	1973	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Halifax	-4:14:24 -	LMT	1902 Jun 15
 			-4:00	Halifax	A%sT	1918
 			-4:00	Canada	A%sT	1919
@@ -1504,7 +1527,7 @@
 Rule	Moncton	1957	1972	-	Oct	lastSun	2:00	0	S
 Rule	Moncton	1993	2006	-	Apr	Sun>=1	0:01	1:00	D
 Rule	Moncton	1993	2006	-	Oct	lastSun	0:01	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Moncton	-4:19:08 -	LMT	1883 Dec  9
 			-5:00	-	EST	1902 Jun 15
 			-4:00	Canada	A%sT	1933
@@ -1533,7 +1556,7 @@
 # For lack of better info, guess this practice began around 1970, contra to
 # Shanks & Pottenger who have this region observing AST/ADT.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Blanc-Sablon -3:48:28 -	LMT	1884
 			-4:00	Canada	A%sT	1970
 			-4:00	-	AST
@@ -1701,19 +1724,10 @@
 # was meant.
 Rule	Toronto	1922	1926	-	Sep	Sun>=15	2:00	0	S
 Rule	Toronto	1924	1927	-	May	Sun>=1	2:00	1:00	D
-# The 1927-to-1939 rules can be expressed more simply as
-# Rule	Toronto	1927	1937	-	Sep	Sun>=25	2:00	0	S
-# Rule	Toronto	1928	1937	-	Apr	Sun>=25	2:00	1:00	D
-# Rule	Toronto	1938	1940	-	Apr	lastSun	2:00	1:00	D
-# Rule	Toronto	1938	1939	-	Sep	lastSun	2:00	0	S
-# The rules below avoid use of Sun>=25
-# (which pre-2004 versions of zic cannot handle).
-Rule	Toronto	1927	1932	-	Sep	lastSun	2:00	0	S
-Rule	Toronto	1928	1931	-	Apr	lastSun	2:00	1:00	D
-Rule	Toronto	1932	only	-	May	1	2:00	1:00	D
-Rule	Toronto	1933	1940	-	Apr	lastSun	2:00	1:00	D
-Rule	Toronto	1933	only	-	Oct	1	2:00	0	S
-Rule	Toronto	1934	1939	-	Sep	lastSun	2:00	0	S
+Rule	Toronto	1927	1937	-	Sep	Sun>=25	2:00	0	S
+Rule	Toronto	1928	1937	-	Apr	Sun>=25	2:00	1:00	D
+Rule	Toronto	1938	1940	-	Apr	lastSun	2:00	1:00	D
+Rule	Toronto	1938	1939	-	Sep	lastSun	2:00	0	S
 Rule	Toronto	1945	1946	-	Sep	lastSun	2:00	0	S
 Rule	Toronto	1946	only	-	Apr	lastSun	2:00	1:00	D
 Rule	Toronto	1947	1949	-	Apr	lastSun	0:00	1:00	D
@@ -1746,7 +1760,7 @@
 # War,... [t]he cities agreed to implement DST during the summer
 # months for the remainder of the war years.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Toronto	-5:17:32 -	LMT	1895
 			-5:00	Canada	E%sT	1919
 			-5:00	Toronto	E%sT	1942 Feb  9  2:00s
@@ -1821,7 +1835,7 @@
 Rule	Winn	1966	1986	-	Apr	lastSun	2:00s	1:00	D
 Rule	Winn	1966	2005	-	Oct	lastSun	2:00s	0	S
 Rule	Winn	1987	2005	-	Apr	Sun>=1	2:00s	1:00	D
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Winnipeg	-6:28:36 -	LMT	1887 Jul 16
 			-6:00	Winn	C%sT	2006
 			-6:00	Canada	C%sT
@@ -1843,6 +1857,13 @@
 # Willett (1914-03) notes that DST "has been in operation ... in the
 # City of Moose Jaw, Saskatchewan, for one year."
 
+# From Paul Eggert (2019-04-26):
+# Chris Pearce's book "The Great Daylight Saving Time Controversy" (2017)
+# says that Regina observed DST in 1914-1917.  No dates and times,
+# unfortunately.  It also says that in 1914 Saskatoon observed DST
+# from 1 June to 6 July, and that DST was also tried out in Davidson,
+# Melfort, and Prince Albert.
+
 # From Paul Eggert (2006-03-22):
 # Shanks & Pottenger say that since 1970 this region has mostly been as Regina.
 # Some western towns (e.g. Swift Current) switched from MST/MDT to CST in 1972.
@@ -1905,7 +1926,7 @@
 Rule	Swift	1959	1961	-	Apr	lastSun	2:00	1:00	D
 Rule	Swift	1959	only	-	Oct	lastSun	2:00	0	S
 Rule	Swift	1960	1961	-	Sep	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Regina	-6:58:36 -	LMT	1905 Sep
 			-7:00	Regina	M%sT	1960 Apr lastSun  2:00
 			-6:00	-	CST
@@ -1936,7 +1957,7 @@
 Rule	Edm	1969	only	-	Oct	lastSun	2:00	0	S
 Rule	Edm	1972	1986	-	Apr	lastSun	2:00	1:00	D
 Rule	Edm	1972	2006	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Edmonton	-7:33:52 -	LMT	1906 Sep
 			-7:00	Edm	M%sT	1987
 			-7:00	Canada	M%sT
@@ -2029,7 +2050,7 @@
 Rule	Vanc	1946	only	-	Oct	13	2:00	0	S
 Rule	Vanc	1947	1961	-	Sep	lastSun	2:00	0	S
 Rule	Vanc	1962	2006	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Vancouver	-8:12:28 -	LMT	1884
 			-8:00	Vanc	P%sT	1987
 			-8:00	Canada	P%sT
@@ -2100,7 +2121,7 @@
 #     varying the manner of reckoning standard time.
 #
 # * Yukon Territory Commissioner's Order 1966-20 Interpretation Ordinance
-#   http://? - no online source found
+#   [no online source found]
 #
 # * Standard Time and Time Zones in Canada; Thomson, Malcolm M.; JRASC,
 #   Vol. 64, pp.129-162; June 1970; SAO/NASA Astrophysics Data System (ADS)
@@ -2133,7 +2154,7 @@
 #     to say eight hours behind Greenwich Time.
 #
 # * O.I.C. 1980/02 INTERPRETATION ACT
-#   http://? - no online source found
+#   [no online source found]
 #
 # * Yukon Daylight Saving Time, YOIC 1987/56
 #   https://www.canlii.org/en/yk/laws/regu/yoic-1987-56/latest/yoic-1987-56.html
@@ -2349,7 +2370,7 @@
 Rule	NT_YK	1980	1986	-	Apr	lastSun	2:00	1:00	D
 Rule	NT_YK	1980	2006	-	Oct	lastSun	2:00	0	S
 Rule	NT_YK	1987	2006	-	Apr	Sun>=1	2:00	1:00	D
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # aka Panniqtuuq
 Zone America/Pangnirtung 0	-	-00	1921 # trading post est.
 			-4:00	NT_YK	A%sT	1995 Apr Sun>=1  2:00
@@ -2496,7 +2517,7 @@
 
 # From Paul Eggert (2001-03-03):
 #
-# http://www.latimes.com/news/nation/20010303/t000018766.html
+# https://www.latimes.com/archives/la-xpm-2001-mar-03-mn-32561-story.html
 # James F. Smith writes in today's LA Times
 # * Sonora will continue to observe standard time.
 # * Last week Mexico City's mayor Andrés Manuel López Obrador decreed that
@@ -2623,7 +2644,7 @@
 Rule	Mexico	2001	only	-	Sep	lastSun	2:00	0	S
 Rule	Mexico	2002	max	-	Apr	Sun>=1	2:00	1:00	D
 Rule	Mexico	2002	max	-	Oct	lastSun	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 # Quintana Roo; represented by Cancún
 Zone America/Cancun	-5:47:04 -	LMT	1922 Jan  1  0:12:56
 			-6:00	-	CST	1981 Dec 23
@@ -2816,7 +2837,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Bahamas	1964	1975	-	Oct	lastSun	2:00	0	S
 Rule	Bahamas	1964	1975	-	Apr	lastSun	2:00	1:00	D
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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
@@ -2831,7 +2852,7 @@
 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		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Barbados	-3:58:29 -	LMT	1924 # Bridgetown
 			-3:58:29 -	BMT	1932 # Bridgetown Mean Time
 			-4:00	Barb	A%sT
@@ -2845,7 +2866,7 @@
 Rule	Belize	1974	only	-	Feb	 9	0:00	0	CST
 Rule	Belize	1982	only	-	Dec	18	0:00	1:00	CDT
 Rule	Belize	1983	only	-	Feb	12	0:00	0	CST
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Belize	-5:52:48 -	LMT	1912 Apr
 			-6:00	Belize	%s
 
@@ -2862,7 +2883,7 @@
 # Friday, the same thing will happen in Bermuda.
 # http://www.theroyalgazette.com/apps/pbcs.dll/article?AID=/20060529/NEWS/105290135
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Atlantic/Bermuda	-4:19:18 -	LMT	1930 Jan  1  2:00 # Hamilton
 			-4:00	-	AST	1974 Apr 28  2:00
 			-4:00	Canada	A%sT	1976
@@ -2884,7 +2905,7 @@
 Rule	CR	1991	only	-	Jul	 1	0:00	0	S
 Rule	CR	1992	only	-	Mar	15	0:00	0	S
 # There are too many San Josés elsewhere, so we'll use 'Costa Rica'.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Costa_Rica	-5:36:13 -	LMT	1890        # San José
 			-5:36:13 -	SJMT	1921 Jan 15 # San José Mean Time
 			-6:00	CR	C%sT
@@ -3090,7 +3111,7 @@
 Rule	Cuba	2012	max	-	Nov	Sun>=1	0:00s	0	S
 Rule	Cuba	2013	max	-	Mar	Sun>=8	0:00s	1:00	D
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Havana	-5:29:28 -	LMT	1890
 			-5:29:36 -	HMT	1925 Jul 19 12:00 # Havana MT
 			-5:00	Cuba	C%sT
@@ -3125,7 +3146,7 @@
 Rule	DR	1970	only	-	Feb	21	0:00	0	EST
 Rule	DR	1971	only	-	Jan	20	0:00	0	EST
 Rule	DR	1972	1974	-	Jan	21	0:00	0	EST
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Santo_Domingo -4:39:36 -	LMT	1890
 			-4:40	-	SDMT	1933 Apr  1 12:00 # S. Dom. MT
 			-5:00	DR	%s	1974 Oct 27
@@ -3140,7 +3161,7 @@
 Rule	Salv	1987	1988	-	Sep	lastSun	0:00	0	S
 # There are too many San Salvadors elsewhere, so use America/El_Salvador
 # instead of America/San_Salvador.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/El_Salvador -5:56:48 -	LMT	1921 # San Salvador
 			-6:00	Salv	C%sT
 
@@ -3173,7 +3194,7 @@
 Rule	Guat	1991	only	-	Sep	 7	0:00	0	S
 Rule	Guat	2006	only	-	Apr	30	0:00	1:00	D
 Rule	Guat	2006	only	-	Oct	 1	0:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Guatemala	-6:02:04 -	LMT	1918 Oct 5
 			-6:00	Guat	C%sT
 
@@ -3259,7 +3280,7 @@
 Rule	Haiti	2012	2015	-	Nov	Sun>=1	2:00	0	S
 Rule	Haiti	2017	max	-	Mar	Sun>=8	2:00	1:00	D
 Rule	Haiti	2017	max	-	Nov	Sun>=1	2:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Port-au-Prince -4:49:20 -	LMT	1890
 			-4:49	-	PPMT	1917 Jan 24 12:00 # P-a-P MT
 			-5:00	Haiti	E%sT
@@ -3298,7 +3319,7 @@
 Rule	Hond	1987	1988	-	Sep	lastSun	0:00	0	S
 Rule	Hond	2006	only	-	May	Sun>=1	0:00	1:00	D
 Rule	Hond	2006	only	-	Aug	Mon>=1	0:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Tegucigalpa -5:48:52 -	LMT	1921 Apr
 			-6:00	Hond	C%sT
 #
@@ -3319,7 +3340,7 @@
 # Neita L. The politician in all of us. Jamaica Observer 2014-09-20
 # http://www.jamaicaobserver.com/columns/The-politician-in-all-of-us_17573647
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Jamaica	-5:07:10 -	LMT	1890        # Kingston
 			-5:07:10 -	KMT	1912 Feb    # Kingston Mean Time
 			-5:00	-	EST	1974
@@ -3327,7 +3348,7 @@
 			-5:00	-	EST
 
 # Martinique
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Martinique	-4:04:20 -      LMT	1890        # Fort-de-France
 			-4:04:20 -	FFMT	1911 May    # Fort-de-France MT
 			-4:00	-	AST	1980 Apr  6
@@ -3391,7 +3412,7 @@
 Rule	Nic	2005	only	-	Oct	Sun>=1	0:00	0	S
 Rule	Nic	2006	only	-	Apr	30	2:00	1:00	D
 Rule	Nic	2006	only	-	Oct	Sun>=1	1:00	0	S
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Managua	-5:45:08 -	LMT	1890
 			-5:45:12 -	MMT	1934 Jun 23 # Managua Mean Time?
 			-6:00	-	CST	1973 May
@@ -3403,7 +3424,7 @@
 			-6:00	Nic	C%sT
 
 # Panama
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Panama	-5:18:08 -	LMT	1890
 			-5:19:36 -	CMT	1908 Apr 22 # Colón Mean Time
 			-5:00	-	EST
@@ -3411,7 +3432,7 @@
 
 # Puerto Rico
 # There are too many San Juans elsewhere, so we'll use 'Puerto_Rico'.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 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
@@ -3423,7 +3444,7 @@
 
 # St Pierre and Miquelon
 # There are too many St Pierres elsewhere, so we'll use 'Miquelon'.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Miquelon	-3:44:40 -	LMT	1911 May 15 # St Pierre
 			-4:00	-	AST	1980 May
 			-3:00	-	-03	1987
@@ -3469,7 +3490,7 @@
 # by March 2018 for TCI. Magnetic Media. 2017-08-25.
 # http://magneticmediatv.com/2017/08/time-change-back-by-march-2018-for-tci/
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Grand_Turk	-4:44:32 -	LMT	1890
 			-5:07:10 -	KMT	1912 Feb # Kingston Mean Time
 			-5:00	-	EST	1979
--- contrib/tzdata/pacificnew.orig
+++ contrib/tzdata/pacificnew
@@ -21,7 +21,7 @@
 ## Rule	Twilite	XXXX	max	uspres	Nov	Sun>=7	2:00	0	S
 ## Rule	Twilite	XXXX	max	nonpres	Oct	lastSun	2:00	0	S
 
-# Zone	NAME			GMTOFF	RULES/SAVE	FORMAT	[UNTIL]
+# Zone	NAME			STDOFF	RULES/SAVE	FORMAT	[UNTIL]
 ## Zone	America/Los_Angeles-PET	-8:00	US		P%sT	XXXX
 ##				-8:00	Twilite		P%sT
 
--- contrib/tzdata/southamerica.orig
+++ contrib/tzdata/southamerica
@@ -396,7 +396,7 @@
 # plus is that this silences a zic complaint that there's no POSIX TZ
 # setting for timestamps past 2038.
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 #
 # Buenos Aires (BA), Capital Federal (CF),
 Zone America/Argentina/Buenos_Aires -3:53:48 - LMT	1894 Oct 31
@@ -577,7 +577,7 @@
 Link America/Curacao America/Aruba
 
 # Bolivia
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/La_Paz	-4:32:36 -	LMT	1890
 			-4:32:36 -	CMT	1931 Oct 15 # Calamarca MT
 			-4:32:36 1:00	BST	1932 Mar 21 # Bolivia ST
@@ -920,14 +920,13 @@
 # removed Tocantins.
 Rule	Brazil	2013	2014	-	Feb	Sun>=15	0:00	0	-
 Rule	Brazil	2015	only	-	Feb	Sun>=22	0:00	0	-
-Rule	Brazil	2016	2022	-	Feb	Sun>=15	0:00	0	-
+Rule	Brazil	2016	2019	-	Feb	Sun>=15	0:00	0	-
 # From Steffen Thorsen (2017-12-18):
 # According to many media sources, next year's DST start in Brazil will move to
-# the first Sunday of November, and it will stay like that for the years after.
+# the first Sunday of November
 # ... https://www.timeanddate.com/news/time/brazil-delays-dst-2018.html
 # From Steffen Thorsen (2017-12-20):
 # http://www.planalto.gov.br/ccivil_03/_ato2015-2018/2017/decreto/D9242.htm
-#
 # From Fábio Gomes (2018-10-04):
 # The Brazilian president just announced a new change on this year DST.
 # It was scheduled to start on November 4th and it was changed to November 18th.
@@ -935,22 +934,21 @@
 # The Brazilian government just announced that the change in DST was
 # canceled....  Maybe the president Michel Temer also woke up one hour
 # earlier today. :)
-Rule	Brazil	2018	max	-	Nov	Sun>=1	0:00	1:00	-
-Rule	Brazil	2023	only	-	Feb	Sun>=22	0:00	0	-
-Rule	Brazil	2024	2025	-	Feb	Sun>=15	0:00	0	-
-Rule	Brazil	2026	only	-	Feb	Sun>=22	0:00	0	-
-Rule	Brazil	2027	2033	-	Feb	Sun>=15	0:00	0	-
-Rule	Brazil	2034	only	-	Feb	Sun>=22	0:00	0	-
-Rule	Brazil	2035	2036	-	Feb	Sun>=15	0:00	0	-
-Rule	Brazil	2037	only	-	Feb	Sun>=22	0:00	0	-
-# From Arthur David Olson (2008-09-29):
-# The next is wrong in some years but is better than nothing.
-Rule	Brazil	2038	max	-	Feb	Sun>=15	0:00	0	-
-
-# The latest ruleset listed above says that the following states observe DST:
+Rule	Brazil	2018	only	-	Nov	Sun>=1	0:00	1:00	-
+# The last ruleset listed above says that the following states observed DST:
 # DF, ES, GO, MG, MS, MT, PR, RJ, RS, SC, SP.
+#
+# From Steffen Thorsen (2019-04-05):
+# According to multiple sources the Brazilian president wants to get rid of DST.
+# https://gmconline.com.br/noticias/politica/bolsonaro-horario-de-verao-deve-acabar-este-ano
+# https://g1.globo.com/economia/noticia/2019/04/05/governo-anuncia-fim-do-horario-de-verao.ghtml
+# From Marcus Diniz (2019-04-25):
+# Brazil no longer has DST changes - decree signed today
+# https://g1.globo.com/politica/noticia/2019/04/25/bolsonaro-assina-decreto-que-acaba-com-o-horario-de-verao.ghtml
+# From Daniel Soares de Oliveira (2019-04-26):
+# http://www.planalto.gov.br/ccivil_03/_Ato2019-2022/2019/Decreto/D9772.htm
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 #
 # Fernando de Noronha (administratively part of PE)
 Zone America/Noronha	-2:09:40 -	LMT	1914
@@ -1258,6 +1256,8 @@
 # https://twitter.com/MinEnergia/status/1029009354001973248
 # "We will keep the new time policy unchanged for at least the next 4 years."
 # So we extend the new rules on Saturdays at 24:00 mainland time indefinitely.
+# From Juan Correa (2019-02-04):
+# http://www.diariooficial.interior.gob.cl/publicaciones/2018/11/23/42212/01/1498738.pdf
 
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	Chile	1927	1931	-	Sep	 1	0:00	1:00	-
@@ -1298,7 +1298,7 @@
 Rule	Chile	2019	max	-	Sep	Sun>=2	4:00u	1:00	-
 # IATA SSIM anomalies: (1992-02) says 1992-03-14;
 # (1996-09) says 1998-03-08.  Ignore these.
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Santiago	-4:42:46 -	LMT	1890
 			-4:42:46 -	SMT	1910 Jan 10 # Santiago Mean Time
 			-5:00	-	-05	1916 Jul  1
@@ -1347,7 +1347,7 @@
 # Palmer has followed Chile.  Prior to that, before the Falklands War,
 # Palmer used to be supplied from Argentina.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Antarctica/Palmer	0	-	-00	1965
 			-4:00	Arg	-04/-03	1969 Oct  5
 			-3:00	Arg	-03/-02	1982 May
@@ -1362,7 +1362,7 @@
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	CO	1992	only	-	May	 3	0:00	1:00	-
 Rule	CO	1993	only	-	Apr	 4	0:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Bogota	-4:56:16 -	LMT	1884 Mar 13
 			-4:56:16 -	BMT	1914 Nov 23 # Bogotá Mean Time
 			-5:00	CO	-05/-04
@@ -1387,7 +1387,7 @@
 # Netherlands as Kingdom Islands.  This won't affect their time zones
 # though, as far as we know.
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Curacao	-4:35:47 -	LMT	1912 Feb 12 # Willemstad
 			-4:30	-	-0430	1965
 			-4:00	-	AST
@@ -1423,7 +1423,7 @@
 Rule	Ecuador	1992	only	-	Nov	28	0:00	1:00	-
 Rule	Ecuador	1993	only	-	Feb	 5	0:00	0	-
 #
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Guayaquil	-5:19:20 -	LMT	1890
 			-5:14:00 -	QMT	1931 # Quito Mean Time
 			-5:00	Ecuador	-05/-04
@@ -1526,7 +1526,7 @@
 Rule	Falk	1986	2000	-	Apr	Sun>=16	0:00	0	-
 Rule	Falk	2001	2010	-	Apr	Sun>=15	2:00	0	-
 Rule	Falk	2001	2010	-	Sep	Sun>=1	2:00	1:00	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Atlantic/Stanley	-3:51:24 -	LMT	1890
 			-3:51:24 -	SMT	1912 Mar 12 # Stanley Mean Time
 			-4:00	Falk	-04/-03	1983 May
@@ -1535,13 +1535,13 @@
 			-3:00	-	-03
 
 # French Guiana
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Cayenne	-3:29:20 -	LMT	1911 Jul
 			-4:00	-	-04	1967 Oct
 			-3:00	-	-03
 
 # Guyana
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# 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
@@ -1635,7 +1635,7 @@
 # http://www.presidencia.gov.py/archivos/documentos/DECRETO1264_ey9r8zai.pdf
 Rule	Para	2013	max	-	Mar	Sun>=22	0:00	0	-
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Asuncion	-3:50:40 -	LMT	1890
 			-3:50:40 -	AMT	1931 Oct 10 # Asunción Mean Time
 			-4:00	-	-04	1972 Oct
@@ -1664,13 +1664,13 @@
 # IATA is ambiguous for 1993/1995; go with Shanks & Pottenger.
 Rule	Peru	1994	only	-	Jan	 1	0:00	1:00	-
 Rule	Peru	1994	only	-	Apr	 1	0:00	0	-
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Lima	-5:08:12 -	LMT	1890
 			-5:08:36 -	LMT	1908 Jul 28 # Lima Mean Time?
 			-5:00	Peru	-05/-04
 
 # South Georgia
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone Atlantic/South_Georgia -2:26:08 -	LMT	1890 # Grytviken
 			-2:00	-	-02
 
@@ -1678,7 +1678,7 @@
 # uninhabited; scientific personnel have wintered
 
 # Suriname
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Paramaribo	-3:40:40 -	LMT	1911
 			-3:40:52 -	PMT	1935     # Paramaribo Mean Time
 			-3:40:36 -	PMT	1945 Oct    # The capital moved?
@@ -1686,7 +1686,7 @@
 			-3:00	-	-03
 
 # Trinidad and Tobago
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone America/Port_of_Spain -4:06:04 -	LMT	1912 Mar 2
 			-4:00	-	AST
 
@@ -1957,7 +1957,7 @@
 # ... published in the official Gazette [2016-04-18], here:
 # http://historico.tsj.gob.ve/gaceta_ext/abril/1842016/E-1842016-4551.pdf
 
-# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	America/Caracas	-4:27:44 -	LMT	1890
 			-4:27:40 -	CMT	1912 Feb 12 # Caracas Mean Time?
 			-4:30	-	-0430	1965 Jan  1  0:00
--- contrib/tzdata/systemv.orig
+++ contrib/tzdata/systemv
@@ -23,7 +23,7 @@
 Rule	SystemV	1976	max	-	Apr	lastSun	2:00	1:00	D
 Rule	SystemV	1976	max	-	Oct	lastSun	2:00	0	S
 
-# Zone	NAME		GMTOFF	RULES/SAVE	FORMAT	[UNTIL]
+# Zone	NAME		STDOFF	RULES/SAVE	FORMAT	[UNTIL]
 ## Zone	SystemV/AST4ADT	-4:00	SystemV		A%sT
 ## Zone	SystemV/EST5EDT	-5:00	SystemV		E%sT
 ## Zone	SystemV/CST6CDT	-6:00	SystemV		C%sT
--- contrib/tzdata/theory.html.orig
+++ contrib/tzdata/theory.html
@@ -88,7 +88,7 @@
 standard for <a
 href="https://en.wikipedia.org/wiki/Unix">UNIX</a>-like systems.
 As of this writing, the current edition of POSIX is: <a
-href="http://pubs.opengroup.org/onlinepubs/9699919799/"> The Open
+href="https://pubs.opengroup.org/onlinepubs/9699919799/"> The Open
 Group Base Specifications Issue 7</a>, IEEE Std 1003.1-2017, 2018
 Edition.
 Because the database's scope encompasses real-world changes to civil
@@ -186,7 +186,7 @@
     href="https://en.wikipedia.org/wiki/ASCII">ASCII</a> letters,
     '<code>.</code>', '<code>-</code>' and '<code>_</code>'.
     Do not use digits, as that might create an ambiguity with <a
-    href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03">POSIX
+    href="https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03">POSIX
     <code>TZ</code> strings</a>.
     A file name component must not exceed 14 characters or start with
     '<code>-</code>'.
@@ -301,7 +301,7 @@
 
 <p>
 Guidelines have evolved with time, and names following old versions of
-this guideline might not follow the current version. When guidelines
+these guidelines might not follow the current version. When guidelines
 have changed, old names continue to be supported. Guideline changes
 have included the following:
 </p>
@@ -330,7 +330,7 @@
 </li>
 
 <li>
-Older versions of this guideline said that
+Older versions of these guidelines said that
 there should typically be at least one name for each <a
 href="https://en.wikipedia.org/wiki/ISO_3166-1"><abbr
 title="International Organization for Standardization">ISO</abbr>
@@ -379,8 +379,8 @@
     special meaning to the
     <a href="https://en.wikipedia.org/wiki/Unix_shell">UNIX shell</a>
     and cause commands like
-    '<code><a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set">set</a>
-    `<a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/date.html">date</a>`</code>'
+    '<code><a href="https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set">set</a>
+    `<a href="https://pubs.opengroup.org/onlinepubs/9699919799/utilities/date.html">date</a>`</code>'
     to have unexpected effects.
     Previous editions of this guideline required upper-case letters, but the
     Congressman who introduced
@@ -955,7 +955,7 @@
   </li>
   <li>
     In POSIX, there is no tamper-proof way for a process to learn the
-    system's best idea of local wall clock.
+    system's best idea of local (wall clock) time.
     This is important for applications that an administrator wants
     used only at certain times &ndash; without regard to whether the
     user has fiddled the
@@ -1052,14 +1052,14 @@
   </li>
   <li>
     A function <code>tzsetwall</code> has been added to arrange for the
-    system's best approximation to local wall clock time to be delivered
+    system's best approximation to local (wall clock) time to be delivered
     by subsequent calls to <code>localtime</code>.
-    Source code for portable applications that "must" run on local wall
-    clock time should call <code>tzsetwall</code>;
+    Source code for portable applications that "must" run on local
+    time should call <code>tzsetwall</code>;
     if such code is moved to "old" systems that do not
     provide <code>tzsetwall</code>, you will not be able to generate an
     executable program.
-    (These functions also arrange for local wall clock time to
+    (These functions also arrange for local time to
     be used if <code>tzset</code> is called &ndash; directly or
     indirectly &ndash; and there is no <code>TZ</code> environment
     variable; portable applications should not, however, rely on this
@@ -1354,11 +1354,11 @@
     Michael Allison and Robert Schmunk,
     "<a href="https://www.giss.nasa.gov/tools/mars24/help/notes.html">Technical
       Notes on Mars Solar Time as Adopted by the Mars24 Sunclock</a>"
-    (2015-06-30).
+    (2018-12-13).
   </li>
   <li>
     Jia-Rui Chong,
-    "<a href="http://articles.latimes.com/2004/jan/14/science/sci-marstime14">Workdays
+    "<a href="https://www.latimes.com/archives/la-xpm-2004-jan-14-sci-marstime14-story.html">Workdays
     Fit for a Martian</a>", <cite>Los Angeles Times</cite>
     (2004-01-14), pp A1, A20&ndash;A21.
   </li>
--- contrib/tzdata/version.orig
+++ contrib/tzdata/version
@@ -1 +1 @@
-2019a
+2019b
--- contrib/tzdata/zishrink.awk.orig
+++ contrib/tzdata/zishrink.awk
@@ -20,7 +20,8 @@
 # Return a shortened rule name representing NAME,
 # and record this relationship to the hash table.
 
-function gen_rule_name(name, n)
+function gen_rule_name(name, \
+		       n)
 {
   # Use a simple memonic: the first two letters.
   n = substr(name, 1, 2)
@@ -29,7 +30,8 @@
   return n
 }
 
-function prehash_rule_names(name)
+function prehash_rule_names( \
+			    name)
 {
   # Rule names are not part of the tzdb API, so substitute shorter
   # ones.  Shortening them consistently from one release to the next
@@ -148,9 +150,11 @@
   }
 }
 
-# Process an input line and save it for later output.
+# Process the input line LINE and save it for later output.
 
-function process_input_line(line, field, end, i, n, startdef)
+function process_input_line(line, \
+			    field, end, i, n, startdef, \
+			    linkline, ruleline, zoneline)
 {
   # Remove comments, normalize spaces, and append a space to each line.
   sub(/#.*/, "", line)
@@ -157,11 +161,10 @@
   line = line " "
   gsub(/[\t ]+/, " ", line)
 
-  # Abbreviate keywords.  Do not abbreviate "Link" to just "L",
-  # as pre-2017c zic erroneously diagnoses "Li" as ambiguous.
-  sub(/^Link /, "Li ", line)
-  sub(/^Rule /, "R ", line)
-  sub(/^Zone /, "Z ", line)
+  # Abbreviate keywords and determine line type.
+  linkline = sub(/^Link /, "L ", line)
+  ruleline = sub(/^Rule /, "R ", line)
+  zoneline = sub(/^Zone /, "Z ", line)
 
   # SystemV rules are not needed.
   if (line ~ /^R SystemV /) return
@@ -169,7 +172,7 @@
   # Replace FooAsia rules with the same rules without "Asia", as they
   # are duplicates.
   if (match(line, /[^ ]Asia /)) {
-    if (line ~ /^R /) return
+    if (ruleline) return
     line = substr(line, 1, RSTART) substr(line, RSTART + 5)
   }
 
@@ -179,21 +182,19 @@
   while (match(line, /:0[^:]/))
     line = substr(line, 1, RSTART - 1) substr(line, RSTART + 2)
 
-  # Abbreviate weekday names.  Do not abbreviate "Sun" and "Sat", as
-  # pre-2017c zic erroneously diagnoses "Su" and "Sa" as ambiguous.
+  # Abbreviate weekday names.
   while (match(line, / (last)?(Mon|Wed|Fri)[ <>]/)) {
     end = RSTART + RLENGTH
     line = substr(line, 1, end - 4) substr(line, end - 1)
   }
-  while (match(line, / (last)?(Tue|Thu)[ <>]/)) {
+  while (match(line, / (last)?(Sun|Tue|Thu|Sat)[ <>]/)) {
     end = RSTART + RLENGTH
     line = substr(line, 1, end - 3) substr(line, end - 1)
   }
 
-  # Abbreviate "max", "only" and month names.
-  # Do not abbreviate "min", as pre-2017c zic erroneously diagnoses "mi"
-  # as ambiguous.
+  # Abbreviate "max", "min", "only" and month names.
   gsub(/ max /, " ma ", line)
+  gsub(/ min /, " mi ", line)
   gsub(/ only /, " o ", line)
   gsub(/ Jan /, " Ja ", line)
   gsub(/ Feb /, " F ", line)
@@ -221,7 +222,7 @@
   n = split(line, field)
 
   # Abbreviate rule names.
-  i = field[1] == "Z" ? 4 : field[1] == "Li" ? 0 : 2
+  i = zoneline ? 4 : linkline ? 0 : 2
   if (i && field[i] ~ /^[^-+0-9]/) {
     if (!rule[field[i]])
       rule[field[i]] = gen_rule_name(field[i])
@@ -231,11 +232,11 @@
   # If this zone supersedes an earlier one, delete the earlier one
   # from the saved output lines.
   startdef = ""
-  if (field[1] == "Z")
+  if (zoneline)
     zonename = startdef = field[2]
-  else if (field[1] == "Li")
+  else if (linkline)
     zonename = startdef = field[3]
-  else if (field[1] == "R")
+  else if (ruleline)
     zonename = ""
   if (startdef) {
     i = zonedef[startdef]
@@ -254,7 +255,8 @@
   output_line[nout++] = line
 }
 
-function output_saved_lines(i)
+function output_saved_lines( \
+			    i)
 {
   for (i = 0; i < nout; i++)
     if (output_line[i])
--- contrib/tzdata/zone.tab.orig
+++ contrib/tzdata/zone.tab
@@ -332,7 +332,10 @@
 RS	+4450+02030	Europe/Belgrade
 RU	+5443+02030	Europe/Kaliningrad	MSK-01 - Kaliningrad
 RU	+554521+0373704	Europe/Moscow	MSK+00 - Moscow area
-RU	+4457+03406	Europe/Simferopol	MSK+00 - Crimea
+# The obsolescent zone.tab format cannot represent Europe/Simferopol well.
+# Put it in RU section and list as UA.  See "territorial claims" above.
+# Programs should use zone1970.tab instead; see above.
+UA	+4457+03406	Europe/Simferopol	MSK+00 - Crimea
 RU	+5836+04939	Europe/Kirov	MSK+00 - Kirov
 RU	+4621+04803	Europe/Astrakhan	MSK+01 - Astrakhan
 RU	+4844+04425	Europe/Volgograd	MSK+01 - Volgograd
--- contrib/tzdata/zone1970.tab.orig
+++ contrib/tzdata/zone1970.tab
@@ -290,7 +290,8 @@
 RS,BA,HR,ME,MK,SI	+4450+02030	Europe/Belgrade
 RU	+5443+02030	Europe/Kaliningrad	MSK-01 - Kaliningrad
 RU	+554521+0373704	Europe/Moscow	MSK+00 - Moscow area
-RU	+4457+03406	Europe/Simferopol	MSK+00 - Crimea
+# Mention RU and UA alphabetically.  See "territorial claims" above.
+RU,UA	+4457+03406	Europe/Simferopol	MSK+00 - Crimea
 RU	+5836+04939	Europe/Kirov	MSK+00 - Kirov
 RU	+4621+04803	Europe/Astrakhan	MSK+01 - Astrakhan
 RU	+4844+04425	Europe/Volgograd	MSK+01 - Volgograd
--- contrib/tzdata/zoneinfo2tdf.pl.orig
+++ contrib/tzdata/zoneinfo2tdf.pl
@@ -28,7 +28,7 @@
 
   $contZone = '';
   if ($type eq 'zone') {
-    # Zone  NAME  GMTOFF  RULES/SAVE  FORMAT  [UNTIL]
+    # Zone  NAME  STDOFF  RULES/SAVE  FORMAT  [UNTIL]
     my $nfields = @fields;
     $nfields >= 5 or warn "bad zone line";
     if ($nfields > 6) {
