IANA 2020d

37 files changed, 1168 insertions, 855 deletions

diff --git a/tz/Makefile b/tz/Makefile
index 610bf19..40b81d1 100644
--- a/tz/Makefile
+++ b/tz/Makefile
@@ -22,13 +22,13 @@ BUGEMAIL=	tz@iana.org
 #	DATAFORM=	main
 # To wait even longer for new features, use:
 #	DATAFORM=	rearguard
+# Rearguard users might also want "ZFLAGS = -b fat"; see below.
 DATAFORM=		main
 
 # Change the line below for your timezone (after finding the one you want in
 # one of the $(TDATA) source files, or adding it to a source file).
 # Alternatively, if you discover you've got the wrong timezone, you can just
-#	zic -l rightzone
-# to correct things.
+# 'zic -l -' to remove it, or 'zic -l rightzone' to change it.
 # Use the command
 #	make zonenames
 # to get a list of the values you can use for LOCALTIME.
@@ -37,33 +37,30 @@ LOCALTIME=	GMT
 
 # 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 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.
-# Alternatively, if you discover you've got the wrong timezone, you can just
-#	zic -p rightzone
-# to correct things.
-# Use the command
-#	make zonenames
-# to get a list of the values you can use for POSIXRULES.
+# Such a setting uses the rules in a 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.
 #
-# If POSIXRULES is empty, no template is installed; this is the intended
-# future default for POSIXRULES.
+# If POSIXRULES is '-', no template is installed; this is the default.
 #
-# Nonempty POSIXRULES is obsolete and should not be relied on, because:
+# Any other value for POSIXRULES is obsolete and should not be relied on, as:
 # * It does not work correctly in popular implementations such as GNU/Linux.
 # * It does not work in the tzdb implementation for timestamps after 2037.
 # * It 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.
+#
+# If, despite the above, you want 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).
+# Alternatively, if you discover you've got the wrong timezone, you can just
+# 'zic -p -' to remove it, or 'zic -p rightzone' to change it.
+# Use the command
+#	make zonenames
+# to get a list of the values you can use for POSIXRULES.
 
-POSIXRULES=	America/New_York
+POSIXRULES=	-
 
 # Also see TZDEFRULESTRING below, which takes effect only
 # if the time zone files cannot be accessed.
@@ -172,9 +169,6 @@ TZDATA_TEXT=	leapseconds tzdata.zi
 
 # For backward-compatibility links for old zone names, use
 #	BACKWARD=	backward
-# If you also want the link US/Pacific-New, even though it is confusing
-# and is planned to be removed from the database eventually, use
-#	BACKWARD=	backward pacificnew
 # To omit these links, use
 #	BACKWARD=
 
@@ -192,10 +186,6 @@ PACKRATDATA=
 
 UTF8_LOCALE=	en_US.utf8
 
-# Since "." may not be in PATH...
-
-YEARISTYPE=	./yearistype
-
 # Non-default libraries needed to link.
 LDLIBS=
 
@@ -253,13 +243,12 @@ LDLIBS=
 #	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
+#  -DZIC_BLOAT_DEFAULT=\"fat\" to default zic's -b option to "fat", and
+#	similarly for "slim".  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.
+#	default is "slim".
 #  -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)
@@ -333,9 +322,8 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
 # add
 #	-DSTD_INSPIRED
 # to the end of the "CFLAGS=" line.  This arranges for the functions
-# "tzsetwall", "offtime", "timelocal", "timegm", "timeoff",
+# "offtime", "timelocal", "timegm", "timeoff",
 # "posix2time", and "time2posix" to be added to the time conversion library.
-# "tzsetwall" is deprecated and is intended to be removed soon; see NEWS.
 # "offtime" is like "gmtime" except that it accepts a second (long) argument
 # that gives an offset to add to the time_t when converting it.
 # "timelocal" is equivalent to "mktime".
@@ -395,7 +383,7 @@ ZIC=		$(zic) $(ZFLAGS)
 
 # To shrink the size of installed TZif files,
 # append "-r @N" to omit data before N-seconds-after-the-Epoch.
-# You can also append "-b slim" if that is not already the default;
+# To grow the files and work around older application bugs, append "-b fat";
 # see ZIC_BLOAT_DEFAULT above.
 # See the zic man page for more about -b and -r.
 ZFLAGS=
@@ -424,26 +412,6 @@ 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
-SGML_DTDDIR= $(SGML_TOPDIR)/share/xml/w3c-sgml-lib/schema/dtd
-SGML_SEARCH_PATH= $(SGML_DTDDIR)/REC-html401-19991224
-SGML_CATALOG_FILES= \
-  $(SGML_TOPDIR)/share/doc/w3-recs/html/www.w3.org/TR/1999/REC-html401-19991224/HTML4.cat:$(SGML_TOPDIR)/share/sgml/html/4.01/HTML4.cat
-
-# The name, arguments and environment of a program to validate HTML 4.01.
-# See <http://openjade.sourceforge.net/doc/> for a validator, and
-# <https://validator.w3.org/source/> for a validation library.
-# Set VALIDATE=':' if you do not have such a program.
-VALIDATE = nsgmls
-VALIDATE_FLAGS = -s -B -wall -wno-unused-param
-VALIDATE_ENV = \
-  SGML_CATALOG_FILES='$(SGML_CATALOG_FILES)' \
-  SGML_SEARCH_PATH='$(SGML_SEARCH_PATH)' \
-  SP_CHARSET_FIXED=YES \
-  SP_ENCODING=UTF-8
-
 # This expensive test requires USE_LTZ.
 # To suppress it, define this macro to be empty.
 CHECK_TIME_T_ALTERNATIVES = check_time_t_alternatives
@@ -538,8 +506,8 @@ DOCS=		$(MANS) date.1 $(MANTXTS) $(WEB_PAGES)
 PRIMARY_YDATA=	africa antarctica asia australasia \
 		europe northamerica southamerica
 YDATA=		$(PRIMARY_YDATA) etcetera
-NDATA=		systemv factory
-TDATA_TO_CHECK=	$(YDATA) $(NDATA) backward pacificnew
+NDATA=		factory
+TDATA_TO_CHECK=	$(YDATA) $(NDATA) backward
 TDATA=		$(YDATA) $(NDATA) $(BACKWARD)
 ZONETABLES=	zone1970.tab zone.tab
 TABDATA=	iso3166.tab $(TZDATA_TEXT) $(ZONETABLES)
@@ -547,7 +515,7 @@ LEAP_DEPS=	leapseconds.awk leap-seconds.list
 TZDATA_ZI_DEPS=	ziguard.awk zishrink.awk version $(TDATA) $(PACKRATDATA)
 DSTDATA_ZI_DEPS= ziguard.awk $(TDATA) $(PACKRATDATA)
 DATA=		$(TDATA_TO_CHECK) backzone iso3166.tab leap-seconds.list \
-			leapseconds yearistype.sh $(ZONETABLES)
+			leapseconds $(ZONETABLES)
 AWK_SCRIPTS=	checklinks.awk checktab.awk leapseconds.awk \
 			ziguard.awk zishrink.awk
 MISC=		$(AWK_SCRIPTS) zoneinfo2tdf.pl
@@ -573,12 +541,10 @@ VERSION_DEPS= \
 		etcetera europe factory iso3166.tab \
 		leap-seconds.list leapseconds.awk localtime.c \
 		newctime.3 newstrftime.3 newtzset.3 northamerica \
-		pacificnew private.h \
-		southamerica strftime.c systemv theory.html \
+		private.h southamerica strftime.c theory.html \
 		time2posix.3 tz-art.html tz-how-to.html tz-link.html \
 		tzfile.5 tzfile.h tzselect.8 tzselect.ksh \
-		workman.sh yearistype.sh \
-		zdump.8 zdump.c zic.8 zic.c \
+		workman.sh zdump.8 zdump.c zic.8 zic.c \
 		ziguard.awk zishrink.awk \
 		zone.tab zone1970.tab zoneinfo2tdf.pl
 
@@ -587,7 +553,7 @@ VERSION_DEPS= \
 
 SHELL=		/bin/sh
 
-all:		tzselect yearistype zic zdump libtz.a $(TABDATA) \
+all:		tzselect zic zdump libtz.a $(TABDATA) \
 		  vanguard.zi main.zi rearguard.zi
 
 ALL:		all date $(ENCHILADA)
@@ -657,10 +623,6 @@ zdump:		$(TZDOBJS)
 zic:		$(TZCOBJS)
 		$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(TZCOBJS) $(LDLIBS)
 
-yearistype:	yearistype.sh
-		cp yearistype.sh yearistype
-		chmod +x yearistype
-
 leapseconds:	$(LEAP_DEPS)
 		$(AWK) -v EXPIRES_LINE=$(EXPIRES_LINE) \
 		  -f leapseconds.awk leap-seconds.list >$@.out
@@ -675,10 +637,9 @@ INSTALLARGS = \
  PACKRATDATA='$(PACKRATDATA)' \
  TZDEFAULT='$(TZDEFAULT)' \
  TZDIR='$(TZDIR)' \
- YEARISTYPE='$(YEARISTYPE)' \
  ZIC='$(ZIC)'
 
-INSTALL_DATA_DEPS = zic leapseconds yearistype tzdata.zi
+INSTALL_DATA_DEPS = zic leapseconds tzdata.zi
 
 # 'make install_data' installs one set of TZif files.
 install_data: $(INSTALL_DATA_DEPS)
@@ -793,7 +754,7 @@ check_character_set: $(ENCHILADA)
 		! grep -Env $(SAFE_LINE)'|^UNUSUAL_OK_'$(OK_CHAR)'*$$' \
 			Makefile && \
 		! grep -Env $(SAFE_SHARP_LINE) $(TDATA_TO_CHECK) backzone \
-			leapseconds yearistype.sh zone.tab && \
+			leapseconds zone.tab && \
 		! grep -Env $(OK_LINE) $(ENCHILADA); \
 	}
 	touch $@
@@ -845,15 +806,13 @@ check_tzs:	$(TZS) $(TZS_NEW)
 check_web:	$(CHECK_WEB_PAGES)
 check_theory.html: theory.html
 check_tz-art.html: tz-art.html
+check_tz-how-to.html: tz-how-to.html
 check_tz-link.html: tz-link.html
-check_theory.html check_tz-art.html check_tz-link.html:
+check_theory.html check_tz-art.html check_tz-how-to.html check_tz-link.html:
 		$(CURL) -sS --url https://validator.w3.org/nu/ -F out=gnu \
 		    -F file=@$$(expr $@ : 'check_\(.*\)') -o $@.out && \
 		  test ! -s $@.out || { cat $@.out; exit 1; }
 		mv $@.out $@
-check_tz-how-to.html: tz-how-to.html
-		$(VALIDATE_ENV) $(VALIDATE) $(VALIDATE_FLAGS) tz-how-to.html
-		touch $@
 
 # Check that zishrink.awk does not alter the data, and that ziguard.awk
 # preserves main-format data.
@@ -883,7 +842,7 @@ clean_misc:
 		rm -fr check_*.dir
 		rm -f *.o *.out $(TIME_T_ALTERNATIVES) \
 		  check_* core typecheck_* \
-		  date tzselect version.h zdump zic yearistype libtz.a
+		  date tzselect version.h zdump zic libtz.a
 clean:		clean_misc
 		rm -fr *.dir tzdb-*/
 		rm -f *.zi $(TZS_NEW)
@@ -1063,10 +1022,14 @@ tzdata$(VERSION)-rearguard.tar.gz: rearguard.zi set-timestamps.out
 		done
 		sed '1s/$$/-rearguard/' \
 		  <version >tzdata$(VERSION)-rearguard.dir/version
+		: The dummy pacificnew pacifies TZUpdater 2.3.1 and earlier.
+		TZ=UTC0 touch -mt 202010122253.00 \
+		  tzdata$(VERSION)-rearguard.dir/pacificnew
 		touch -cmr version tzdata$(VERSION)-rearguard.dir/version
 		LC_ALL=C && export LC_ALL && \
 		  (cd tzdata$(VERSION)-rearguard.dir && \
-		   tar $(TARFLAGS) -cf - $(COMMON) $(DATA) $(MISC) | \
+		   tar $(TARFLAGS) -cf - \
+			$(COMMON) $(DATA) $(MISC) pacificnew | \
 		     gzip $(GZIPFLAGS)) >$@.out
 		mv $@.out $@
 
diff --git a/tz/NEWS b/tz/NEWS
index 321e090..328face 100644
--- a/tz/NEWS
+++ b/tz/NEWS
@@ -1,5 +1,114 @@
 News for the tz database
 
+Release 2020d - 2020-10-21 11:24:13 -0700
+
+  Briefly:
+    Palestine ends DST earlier than predicted, on 2020-10-24.
+
+  Changes to past and future timestamps
+
+    Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
+    as previously predicted (thanks to Sharef Mustafa.)  Its
+    2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
+    Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
+    its spring 2020 transition was on March 28 at 00:00, not March 27
+    (thanks to Pierre Cashon.)  This affects Asia/Gaza and
+    Asia/Hebron.  Assume future spring and fall transitions will be on
+    the Saturday preceding the last Sunday of March and October,
+    respectively.
+
+
+Release 2020c - 2020-10-16 11:15:53 -0700
+
+  Briefly:
+    Fiji starts DST later than usual, on 2020-12-20.
+
+  Changes to future timestamps
+
+    Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
+    previously predicted.  DST will still end on 2021-01-17.
+    (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
+    the later-than-usual start date is a one-time departure from the
+    recent pattern.
+
+  Changes to build procedure
+
+    Rearguard tarballs now contain an empty file pacificnew.
+    Some older downstream software expects this file to exist.
+    (Problem reported by Mike Cullinan.)
+
+
+Release 2020b - 2020-10-06 18:35:04 -0700
+
+  Briefly:
+    Revised predictions for Morocco's changes starting in 2023.
+    Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
+    Macquarie Island has stayed in sync with Tasmania since 2011.
+    Casey, Antarctica is at +08 in winter and +11 in summer.
+    zic no longer supports -y, nor the TYPE field of Rules.
+
+  Changes to future timestamps
+
+    Morocco's spring-forward after Ramadan is now predicted to occur
+    no sooner than two days after Ramadan, instead of one day.
+    (Thanks to Milamber.)  The first altered prediction is for 2023,
+    now predicted to spring-forward on April 30 instead of April 23.
+
+  Changes to past and future timestamps
+
+   Casey Station, Antarctica has been using +08 in winter and +11 in
+   summer since 2018.  The most recent transition from +08 to +11 was
+   2020-10-04 00:01.  Also, Macquarie Island has been staying in
+   sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
+
+  Changes to past and future time zone abbreviations and DST flags
+
+    Canada's Yukon, represented by America/Whitehorse and
+    America/Dawson, changes its time zone rules from -08/-07 to
+    permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
+    This change affects only the time zone abbreviation (MST vs PDT)
+    and daylight saving flag for the period between the two dates.
+    (Thanks to Andrew G. Smith.)
+
+  Changes to past timestamps
+
+    Correct several transitions for Hungary for 1918/1983.
+    For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
+    (Thanks to Géza Nyáry.)  Also, the 1890 transition to standard
+    time was on 11-01, not 10-01 (thanks to Michael Deckers).
+
+    The 1891 French transition was on March 16, not March 15.  The
+    1911-03-11 French transition was at midnight, not a minute later.
+    Monaco's transitions were on 1892-06-01 and 1911-03-29, not
+    1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
+
+  Changes to code
+
+    Support for zic's long-obsolete '-y YEARISTYPE' option has been
+    removed and, with it, so has support for the TYPE field in Rule
+    lines, which is now reserved for compatibility with earlier zic.
+    These features were previously deprecated in release 2015f.
+    (Thanks to Tim Parenti.)
+
+    zic now defaults to '-b slim' instead of to '-b fat'.
+
+    zic's new '-l -' and '-p -' options uninstall any existing
+    localtime and posixrules files, respectively.
+
+    The undocumented and ineffective tzsetwall function has been
+    removed.
+
+  Changes to build procedure
+
+    The Makefile now defaults POSIXRULES to '-', so the posixrules
+    feature (obsolete as of 2019b) is no longer installed by default.
+
+  Changes to documentation and commentary
+
+    The long-obsolete files pacificnew, systemv, and yearistype.sh have
+    been removed from the distribution.  (Thanks to Tim Parenti.)
+
+
 Release 2020a - 2020-04-23 16:03:47 -0700
 
   Briefly:
diff --git a/tz/README b/tz/README
index dd6fcf7..145aacd 100644
--- a/tz/README
+++ b/tz/README
@@ -20,6 +20,8 @@ substituting your desired installation directory for "$HOME/tzdir":
 	make TOPDIR=$HOME/tzdir install
 	$HOME/tzdir/usr/bin/zdump -v America/Los_Angeles
 
+See the file tz-how-to.html for examples of how to read the data files.
+
 This database of historical local time information has several goals:
 
  * Provide a compendium of data about the history of civil time that
diff --git a/tz/africa b/tz/africa
index 724744f..566436b 100644
--- a/tz/africa
+++ b/tz/africa
@@ -64,7 +64,7 @@
 # Corrections are welcome.
 
 # Algeria
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Algeria	1916	only	-	Jun	14	23:00s	1:00	S
 Rule	Algeria	1916	1919	-	Oct	Sun>=1	23:00s	0	-
 Rule	Algeria	1917	only	-	Mar	24	23:00s	1:00	S
@@ -87,10 +87,9 @@ Rule	Algeria	1978	only	-	Mar	24	 1:00	1:00	S
 Rule	Algeria	1978	only	-	Sep	22	 3:00	0	-
 Rule	Algeria	1980	only	-	Apr	25	 0:00	1:00	S
 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.
+# See Europe/Paris for PMT-related transitions.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Africa/Algiers	0:12:12 -	LMT	1891 Mar 15  0:01
+Zone	Africa/Algiers	0:12:12 -	LMT	1891 Mar 16
 			0:09:21	-	PMT	1911 Mar 11 # Paris Mean Time
 			0:00	Algeria	WE%sT	1940 Feb 25  2:00
 			1:00	Algeria	CE%sT	1946 Oct  7
@@ -176,7 +175,7 @@ Link Africa/Abidjan Atlantic/St_Helena	# St Helena
 # Egypt was mean noon at the Great Pyramid, 2:04:30.5, but apparently this
 # did not apply to Cairo, Alexandria, or Port Said.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Egypt	1940	only	-	Jul	15	0:00	1:00	S
 Rule	Egypt	1940	only	-	Oct	 1	0:00	0	-
 Rule	Egypt	1941	only	-	Apr	15	0:00	1:00	S
@@ -411,7 +410,7 @@ Zone	Africa/Cairo	2:05:09 -	LMT	1900 Oct
 # now Ghana observed different DST regimes in different years.  For
 # lack of better info, use Shanks except treat the minus sign as a
 # typo, and assume DST started in 1920 not 1936.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -501,7 +500,7 @@ Zone	Africa/Monrovia	-0:43:08 -	LMT	1882
 # From Paul Eggert (2013-10-25):
 # For now, assume they're reverting to the pre-2012 rules of permanent UT +02.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Libya	1951	only	-	Oct	14	2:00	1:00	S
 Rule	Libya	1952	only	-	Jan	 1	0:00	0	-
 Rule	Libya	1953	only	-	Oct	 9	2:00	1:00	S
@@ -624,7 +623,7 @@ Zone	Africa/Tripoli	0:52:44 -	LMT	1920
 # "The trial ended on March 29, 2009, when the clocks moved back by one hour
 # at 2am (or 02:00) local time..."
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule Mauritius	1982	only	-	Oct	10	0:00	1:00	-
 Rule Mauritius	1983	only	-	Mar	21	0:00	0	-
 Rule Mauritius	2008	only	-	Oct	lastSun	2:00	1:00	-
@@ -875,17 +874,30 @@ Zone Indian/Mauritius	3:50:00 -	LMT	1907 # Port Louis
 # https://maroc-diplomatique.net/maroc-le-retour-a-lheure-gmt-est-prevu-dimanche-prochain/
 # http://aujourdhui.ma/actualite/gmt1-retour-a-lheure-normale-dimanche-prochain-1
 #
-# From Paul Eggert (2020-04-14):
+# From Milamber (2020-05-31)
+# In Morocco (where I live), the end of Ramadan (Arabic month) is followed by
+# the Eid al-Fitr, and concretely it's 1 or 2 day offs for the people (with
+# traditional visiting of family, big lunches/dinners, etc.).  So for this
+# year the astronomical calculations don't include the following 2 days off in
+# the calc.  These 2 days fall in a Sunday/Monday, so it's not acceptable by
+# people to have a time shift during these 2 days off.  Perhaps you can modify
+# the (predicted) rules for next years: if the end of Ramadan is a (probable)
+# Friday or Saturday (and so the 2 days off are on a weekend), the next time
+# shift will be the next weekend.
+#
+# From Paul Eggert (2020-05-31):
 # For now, guess that in the future Morocco will fall back at 03:00
 # the last Sunday before Ramadan, and spring forward at 02:00 the
-# first Sunday after the day after Ramadan.  To implement this,
-# transition dates for 2021 through 2087 were determined by running
-# the following program under GNU Emacs 26.3.
-# (let ((islamic-year 1442))
+# first Sunday after two days after Ramadan.  To implement this,
+# transition dates and times for 2019 through 2087 were determined by
+# running the following program under GNU Emacs 26.3.  (This algorithm
+# also produces the correct transition dates for 2016 through 2018,
+# though the times differ due to Morocco's time zone change in 2018.)
+# (let ((islamic-year 1440))
 #   (require 'cal-islam)
 #   (while (< islamic-year 1511)
 #     (let ((a (calendar-islamic-to-absolute (list 9 1 islamic-year)))
-#           (b (1+ (calendar-islamic-to-absolute (list 10 1 islamic-year))))
+#           (b (+ 2 (calendar-islamic-to-absolute (list 10 1 islamic-year))))
 #           (sunday 0))
 #       (while (/= sunday (mod (setq a (1- a)) 7)))
 #       (while (/= sunday (mod b 7))
@@ -900,7 +912,7 @@ Zone Indian/Mauritius	3:50:00 -	LMT	1907 # Port Louis
 #         (car (cdr (cdr b))) (calendar-month-name (car b) t) (car (cdr b)))))
 #     (setq islamic-year (+ 1 islamic-year))))
 
-# RULE	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Morocco	1939	only	-	Sep	12	 0:00	1:00	-
 Rule	Morocco	1939	only	-	Nov	19	 0:00	0	-
 Rule	Morocco	1940	only	-	Feb	25	 0:00	1:00	-
@@ -951,7 +963,7 @@ Rule	Morocco	2021	only	-	May	16	 2:00	0	-
 Rule	Morocco	2022	only	-	Mar	27	 3:00	-1:00	-
 Rule	Morocco	2022	only	-	May	 8	 2:00	0	-
 Rule	Morocco	2023	only	-	Mar	19	 3:00	-1:00	-
-Rule	Morocco	2023	only	-	Apr	23	 2:00	0	-
+Rule	Morocco	2023	only	-	Apr	30	 2:00	0	-
 Rule	Morocco	2024	only	-	Mar	10	 3:00	-1:00	-
 Rule	Morocco	2024	only	-	Apr	14	 2:00	0	-
 Rule	Morocco	2025	only	-	Feb	23	 3:00	-1:00	-
@@ -967,7 +979,7 @@ Rule	Morocco	2029	only	-	Feb	18	 2:00	0	-
 Rule	Morocco	2029	only	-	Dec	30	 3:00	-1:00	-
 Rule	Morocco	2030	only	-	Feb	10	 2:00	0	-
 Rule	Morocco	2030	only	-	Dec	22	 3:00	-1:00	-
-Rule	Morocco	2031	only	-	Jan	26	 2:00	0	-
+Rule	Morocco	2031	only	-	Feb	 2	 2:00	0	-
 Rule	Morocco	2031	only	-	Dec	14	 3:00	-1:00	-
 Rule	Morocco	2032	only	-	Jan	18	 2:00	0	-
 Rule	Morocco	2032	only	-	Nov	28	 3:00	-1:00	-
@@ -983,7 +995,7 @@ 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	2038	only	-	Nov	 7	 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	-
@@ -999,7 +1011,7 @@ 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	2046	only	-	Aug	12	 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	-
@@ -1015,7 +1027,7 @@ 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	2054	only	-	May	17	 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	-
@@ -1031,7 +1043,7 @@ 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	-	Feb	19	 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	-
@@ -1047,7 +1059,7 @@ 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	2069	only	-	Nov	24	 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	-
@@ -1063,7 +1075,7 @@ 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	2077	only	-	Aug	29	 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	-
@@ -1073,13 +1085,13 @@ 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	2082	only	-	Jul	 5	 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	2085	only	-	Jun	 3	 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	-
@@ -1180,7 +1192,7 @@ Link Africa/Maputo Africa/Lusaka	# Zambia
 # Use plain "WAT" and "CAT" for the time zone abbreviations, to be compatible
 # with Namibia's neighbors.
 
-# RULE	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # Vanguard section, for zic and other parsers that support negative DST.
 Rule	Namibia	1994	only	-	Mar	21	0:00	-1:00	WAT
 Rule	Namibia	1994	2017	-	Sep	Sun>=1	2:00	0	CAT
@@ -1303,7 +1315,7 @@ Zone	Indian/Mahe	3:41:48 -	LMT	1906 Jun # Victoria
 # See Africa/Nairobi.
 
 # South Africa
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -1336,7 +1348,7 @@ Link Africa/Johannesburg Africa/Mbabane    # Eswatini
 # Abdalla of NTC, archived at:
 # https://mm.icann.org/pipermail/tz/2017-October/025333.html
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Sudan	1970	only	-	May	 1	0:00	1:00	S
 Rule	Sudan	1970	1985	-	Oct	15	0:00	0	-
 Rule	Sudan	1971	only	-	Apr	30	0:00	1:00	S
@@ -1424,7 +1436,7 @@ Zone	Africa/Juba	2:06:28 -	LMT	1931
 # http://www.almadenahnews.com/newss/news.php?c=118&id=38036
 # http://www.worldtimezone.com/dst_news/dst_news_tunis02.html
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Tunisia	1939	only	-	Apr	15	23:00s	1:00	S
 Rule	Tunisia	1939	only	-	Nov	18	23:00s	0	-
 Rule	Tunisia	1940	only	-	Feb	25	23:00s	1:00	S
@@ -1451,9 +1463,7 @@ Rule	Tunisia	2005	only	-	Sep	30	 1:00s	0	-
 Rule	Tunisia	2006	2008	-	Mar	lastSun	 2:00s	1:00	S
 Rule	Tunisia	2006	2008	-	Oct	lastSun	 2:00s	0	-
 
-# 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.
+# See Europe/Paris for PMT-related transitions.
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Tunis	0:40:44 -	LMT	1881 May 12
 			0:09:21	-	PMT	1911 Mar 11 # Paris Mean Time
diff --git a/tz/antarctica b/tz/antarctica
index 2059983..ed750a8 100644
--- a/tz/antarctica
+++ b/tz/antarctica
@@ -70,15 +70,30 @@
 # Australian Antarctica Division informed us that Casey changed time
 # zone to UTC+11 in "the morning of 22nd October 2016".
 
+# From Steffen Thorsen (2020-10-02, as corrected):
+# Based on information we have received from the Australian Antarctic
+# Division, Casey station and Macquarie Island station will move to Tasmanian
+# daylight savings time on Sunday 4 October. This will take effect from 0001
+# hrs on Sunday 4 October 2020 and will mean Casey and Macquarie Island will
+# be on the same time zone as Hobart.  Some past dates too for this 3 hour
+# time change back and forth between UTC+8 and UTC+11 for Casey:
+# - 2018 Oct  7 4:00 - 2019 Mar 17 3:00 - 2019 Oct  4 3:00 - 2020 Mar  8 3:00
+# and now - 2020 Oct  4 0:01
+
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone Antarctica/Casey	0	-	-00	1969
-			8:00	-	+08	2009 Oct 18  2:00
+Zone Antarctica/Casey	 0	-	-00	1969
+			 8:00	-	+08	2009 Oct 18  2:00
 			11:00	-	+11	2010 Mar  5  2:00
-			8:00	-	+08	2011 Oct 28  2:00
+			 8:00	-	+08	2011 Oct 28  2:00
 			11:00	-	+11	2012 Feb 21 17:00u
-			8:00	-	+08	2016 Oct 22
+			 8:00	-	+08	2016 Oct 22
 			11:00	-	+11	2018 Mar 11  4:00
-			8:00	-	+08
+			 8:00	-	+08	2018 Oct  7  4:00
+			11:00	-	+11	2019 Mar 17  3:00
+			 8:00	-	+08	2019 Oct  4  3:00
+			11:00	-	+11	2020 Mar  8  3:00
+			 8:00	-	+08	2020 Oct  4  0:01
+			11:00	-	+11
 Zone Antarctica/Davis	0	-	-00	1957 Jan 13
 			7:00	-	+07	1964 Nov
 			0	-	-00	1969 Feb
@@ -224,7 +239,7 @@ Zone Antarctica/Syowa	0	-	-00	1957 Jan 29
 # suggested by Bengt-Inge Larsson comment them out for now, and approximate
 # with only UTC and CEST.  Uncomment them when 2014b is more prevalent.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 #Rule	Troll	2005	max	-	Mar	 1	1:00u	1:00	+01
 Rule	Troll	2005	max	-	Mar	lastSun	1:00u	2:00	+02
 #Rule	Troll	2005	max	-	Oct	lastSun	1:00u	1:00	+01
diff --git a/tz/asia b/tz/asia
index 106efad..3ebfcb4 100644
--- a/tz/asia
+++ b/tz/asia
@@ -70,7 +70,7 @@
 ###############################################################################
 
 # These rules are stolen from the 'europe' file.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	EUAsia	1981	max	-	Mar	lastSun	 1:00u	1:00	S
 Rule	EUAsia	1979	1995	-	Sep	lastSun	 1:00u	0	-
 Rule	EUAsia	1996	max	-	Oct	lastSun	 1:00u	0	-
@@ -114,7 +114,7 @@ Zone	Asia/Kabul	4:36:48 -	LMT	1890
 # or
 # (brief)
 # http://www.worldtimezone.com/dst_news/dst_news_armenia03.html
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -140,7 +140,7 @@ Zone	Asia/Yerevan	2:58:00 -	LMT	1924 May  2
 # http://vestnikkavkaza.net/news/Azerbaijani-Cabinet-of-Ministers-cancels-daylight-saving-time.html
 # http://en.apa.az/xeber_azerbaijan_abolishes_daylight_savings_ti_240862.html
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -227,7 +227,7 @@ Zone	Asia/Baku	3:19:24 -	LMT	1924 May  2
 # http://www.thedailystar.net/newDesign/latest_news.php?nid=22817
 # http://www.worldtimezone.com/dst_news/dst_news_bangladesh06.html
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Dhaka	2009	only	-	Jun	19	23:00	1:00	-
 Rule	Dhaka	2009	only	-	Dec	31	24:00	0	-
 
@@ -303,7 +303,7 @@ Zone	Asia/Yangon	6:24:47 -	LMT	1880        # or Rangoon
 # generally esteemed a success, it was announced early in 1920 that it would
 # not be repeated."
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Shang	1919	only	-	Apr	12	24:00	1:00	D
 Rule	Shang	1919	only	-	Sep	30	24:00	0	S
 
@@ -399,7 +399,7 @@ Rule	Shang	1919	only	-	Sep	30	24:00	0	S
 # the Yangtze river delta area during that period of time although the scope
 # of such use will need to be investigated to determine.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Shang	1940	only	-	Jun	 1	 0:00	1:00	D
 Rule	Shang	1940	only	-	Oct	12	24:00	0	S
 Rule	Shang	1941	only	-	Mar	15	 0:00	1:00	D
@@ -462,7 +462,7 @@ Rule	Shang	1948	1949	-	Sep	30	24:00	0	S #plan
 # to begin on 17 April.
 # http://data.people.com.cn/pic/101p/1988/04/1988041201.jpg
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	PRC	1986	only	-	May	 4	 2:00	1:00	D
 Rule	PRC	1986	1991	-	Sep	Sun>=11	 2:00	0	S
 Rule	PRC	1987	1991	-	Apr	Sun>=11	 2:00	1:00	D
@@ -846,7 +846,7 @@ Zone	Asia/Urumqi	5:50:20	-	LMT	1928
 # or dates for the 1942 and 1945 transitions.
 # The Japanese occupation of Hong Kong began 1941-12-25.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 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
@@ -973,7 +973,7 @@ Zone	Asia/Hong_Kong	7:36:42 -	LMT	1904 Oct 30  0:36:42
 # until 1945-09-21 at 01:00, overriding Shanks & Pottenger.
 # Likewise, use Yu-Cheng Chuang's data for DST in Taiwan.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Taiwan	1946	only	-	May	15	0:00	1:00	D
 Rule	Taiwan	1946	only	-	Oct	1	0:00	0	S
 Rule	Taiwan	1947	only	-	Apr	15	0:00	1:00	D
@@ -1099,7 +1099,7 @@ Zone	Asia/Taipei	8:06:00 -	LMT	1896 Jan  1
 # The 1904 decree says that Macau changed from the meridian of
 # Fortaleza do Monte, presumably the basis for the 7:34:10 for LMT.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Macau	1942	1943	-	Apr	30	23:00	1:00	-
 Rule	Macau	1942	only	-	Nov	17	23:00	0	-
 Rule	Macau	1943	only	-	Sep	30	23:00	0	S
@@ -1157,7 +1157,7 @@ Zone	Asia/Macau	7:34:10 -	LMT	1904 Oct 30
 # Cyprus to remain united in time.  Cyprus Mail 2017-10-17.
 # https://cyprus-mail.com/2017/10/17/cyprus-remain-united-time/
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Cyprus	1975	only	-	Apr	13	0:00	1:00	S
 Rule	Cyprus	1975	only	-	Oct	12	0:00	0	-
 Rule	Cyprus	1976	only	-	May	15	0:00	1:00	S
@@ -1534,7 +1534,7 @@ Zone Asia/Jayapura	9:22:48 -	LMT	1932 Nov
 # be changed back to its previous state on the 24 hours of the
 # thirtieth day of Shahrivar.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Iran	1978	1980	-	Mar	20	24:00	1:00	-
 Rule	Iran	1978	only	-	Oct	20	24:00	0	-
 Rule	Iran	1979	only	-	Sep	18	24:00	0	-
@@ -1676,7 +1676,7 @@ Zone	Asia/Tehran	3:25:44	-	LMT	1916
 # We have published a short article in English about the change:
 # https://www.timeanddate.com/news/time/iraq-dumps-daylight-saving.html
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Iraq	1982	only	-	May	1	0:00	1:00	-
 Rule	Iraq	1982	1984	-	Oct	1	0:00	0	-
 Rule	Iraq	1983	only	-	Mar	31	0:00	1:00	-
@@ -1699,6 +1699,10 @@ Zone	Asia/Baghdad	2:57:40	-	LMT	1890
 
 # Israel
 
+# For more info about the motivation for DST in Israel, see:
+# Barak Y. Israel's Daylight Saving Time controversy. Israel Affairs.
+# 2020-08-11. https://doi.org/10.1080/13537121.2020.1806564
+
 # From Ephraim Silverberg (2001-01-11):
 #
 # I coined "IST/IDT" circa 1988.  Until then there were three
@@ -1720,7 +1724,7 @@ Zone	Asia/Baghdad	2:57:40	-	LMT	1890
 # family is from India).
 
 # From Shanks & Pottenger:
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Zion	1940	only	-	Jun	 1	0:00	1:00	D
 Rule	Zion	1942	1944	-	Nov	 1	0:00	0	S
 Rule	Zion	1943	only	-	Apr	 1	2:00	1:00	D
@@ -1812,7 +1816,7 @@ Rule	Zion	1988	only	-	Sep	 4	0:00	0	S
 # (except in 2002) is three nights before Yom Kippur [Day of Atonement]
 # (the eve of the 7th of Tishrei in the lunar Hebrew calendar).
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Zion	1989	only	-	Apr	30	0:00	1:00	D
 Rule	Zion	1989	only	-	Sep	 3	0:00	0	S
 Rule	Zion	1990	only	-	Mar	25	0:00	1:00	D
@@ -1828,7 +1832,7 @@ Rule	Zion	1993	only	-	Sep	 5	0:00	0	S
 # Ministry of Interior, Jerusalem, Israel.  The spokeswoman can be reached by
 # calling the office directly at 972-2-6701447 or 972-2-6701448.
 
-# Rule	NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Zion	1994	only	-	Apr	 1	0:00	1:00	D
 Rule	Zion	1994	only	-	Aug	28	0:00	0	S
 Rule	Zion	1995	only	-	Mar	31	0:00	1:00	D
@@ -1848,7 +1852,7 @@ Rule	Zion	1995	only	-	Sep	 3	0:00	0	S
 #
 #       where YYYY is the relevant year.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Zion	1996	only	-	Mar	15	0:00	1:00	D
 Rule	Zion	1996	only	-	Sep	16	0:00	0	S
 Rule	Zion	1997	only	-	Mar	21	0:00	1:00	D
@@ -1871,7 +1875,7 @@ Rule	Zion	1999	only	-	Sep	 3	2:00	0	S
 #
 #	ftp://ftp.cs.huji.ac.il/pub/tz/announcements/2000-2004.ps.gz
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Zion	2000	only	-	Apr	14	2:00	1:00	D
 Rule	Zion	2000	only	-	Oct	 6	1:00	0	S
 Rule	Zion	2001	only	-	Apr	 9	1:00	1:00	D
@@ -1893,7 +1897,7 @@ Rule	Zion	2004	only	-	Sep	22	1:00	0	S
 #
 #	ftp://ftp.cs.huji.ac.il/pub/tz/announcements/2005+beyond.ps
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 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	only	-	Oct	 1	2:00	0	S
@@ -1913,7 +1917,7 @@ Rule	Zion	2012	only	-	Sep	23	2:00	0	S
 # As of 2013, DST starts at 02:00 on the Friday before the last Sunday
 # in March.  DST ends at 02:00 on the last Sunday of October.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Zion	2013	max	-	Mar	Fri>=23	2:00	1:00	D
 Rule	Zion	2013	max	-	Oct	lastSun	2:00	0	S
 
@@ -2013,7 +2017,7 @@ Zone	Asia/Jerusalem	2:20:54 -	LMT	1880
 # do in any POSIX or C platform.  The "25:00" assumes zic from 2007 or later,
 # which should be safe now.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Japan	1948	only	-	May	Sat>=1	24:00	1:00	D
 Rule	Japan	1948	1951	-	Sep	Sat>=8	25:00	0	S
 Rule	Japan	1949	only	-	Apr	Sat>=1	24:00	1:00	D
@@ -2090,7 +2094,7 @@ Zone	Asia/Tokyo	9:18:59	-	LMT	1887 Dec 31 15:00u
 # From Paul Eggert (2013-12-11):
 # As Steffen suggested, consider the past 21-month experiment to be DST.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Jordan	1973	only	-	Jun	6	0:00	1:00	S
 Rule	Jordan	1973	1975	-	Oct	1	0:00	0	-
 Rule	Jordan	1974	1977	-	May	1	0:00	1:00	S
@@ -2416,7 +2420,7 @@ Zone	Asia/Oral	3:25:24	-	LMT	1924 May  2 # or Ural'sk
 # Our government cancels daylight saving time 6th of August 2005.
 # From 2005-08-12 our GMT-offset is +6, w/o any daylight saving.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Kyrgyz	1992	1996	-	Apr	Sun>=7	0:00s	1:00	-
 Rule	Kyrgyz	1992	1996	-	Sep	lastSun	0:00	0	-
 Rule	Kyrgyz	1997	2005	-	Mar	lastSun	2:30	1:00	-
@@ -2472,7 +2476,7 @@ Zone	Asia/Bishkek	4:58:24 -	LMT	1924 May  2
 # follow and continued to use GMT+9:00 for interoperability.
 
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	ROK	1948	only	-	Jun	 1	 0:00	1:00	D
 Rule	ROK	1948	only	-	Sep	12	24:00	0	S
 Rule	ROK	1949	only	-	Apr	 3	 0:00	1:00	D
@@ -2560,7 +2564,7 @@ Zone	Asia/Pyongyang	8:23:00 -	LMT	1908 Apr  1
 
 
 # Lebanon
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Lebanon	1920	only	-	Mar	28	0:00	1:00	S
 Rule	Lebanon	1920	only	-	Oct	25	0:00	0	-
 Rule	Lebanon	1921	only	-	Apr	3	0:00	1:00	S
@@ -2590,7 +2594,7 @@ Zone	Asia/Beirut	2:22:00 -	LMT	1880
 			2:00	Lebanon	EE%sT
 
 # Malaysia
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	NBorneo	1935	1941	-	Sep	14	0:00	0:20	-
 Rule	NBorneo	1935	1941	-	Dec	14	0:00	0	-
 #
@@ -2735,7 +2739,7 @@ Zone	Indian/Maldives	4:54:00 -	LMT	1880 # Malé
 # September daylight saving time ends.  Source:
 # http://zasag.mn/news/view/8969
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Mongol	1983	1984	-	Apr	1	0:00	1:00	-
 Rule	Mongol	1983	only	-	Oct	1	0:00	0	-
 # Shanks & Pottenger and IATA SSIM say 1990s switches occurred at 00:00,
@@ -2923,7 +2927,7 @@ Zone	Asia/Kathmandu	5:41:16 -	LMT	1920
 # "People laud PM's announcement to end DST"
 # http://www.app.com.pk/en_/index.php?option=com_content&task=view&id=99374&Itemid=2
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule Pakistan	2002	only	-	Apr	Sun>=2	0:00	1:00	S
 Rule Pakistan	2002	only	-	Oct	Sun>=2	0:00	0	-
 Rule Pakistan	2008	only	-	Jun	1	0:00	1:00	S
@@ -3217,15 +3221,42 @@ Zone	Asia/Karachi	4:28:12 -	LMT	1907
 
 # From Sharef Mustafa (2019-10-18):
 # Palestine summer time will end on midnight Oct 26th 2019 ...
-# http://www.palestinecabinet.gov.ps/website/ar/ViewDetails?ID=43948
 #
-# From Paul Eggert (2019-04-10):
-# For now, guess spring-ahead transitions are March's last Friday at 00:00.
+# From Steffen Thorsen (2020-10-20):
+# Some sources such as these say, and display on clocks, that DST ended at
+# midnight last year...
+# https://www.amad.ps/ar/post/320006
+#
+# From Tim Parenti (2020-10-20):
+# The report of the Palestinian Cabinet meeting of 2019-10-14 confirms
+# a decision on (translated): "The start of the winter time in Palestine, by
+# delaying the clock by sixty minutes, starting from midnight on Friday /
+# Saturday corresponding to 26/10/2019."
+# http://www.palestinecabinet.gov.ps/portal/meeting/details/43948
+
+# From Sharef Mustafa (2020-10-20):
+# As per the palestinian cabinet announcement yesterday , the day light saving
+# shall [end] on Oct 24th 2020 at 01:00AM by delaying the clock by 60 minutes.
+# http://www.palestinecabinet.gov.ps/portal/Meeting/Details/51584
+
+# From Tim Parenti (2020-10-20):
+# Predict future fall transitions at 01:00 on the Saturday preceding October's
+# last Sunday (i.e., Sat>=24).  This is consistent with our predictions since
+# 2016, although the time of the change differed slightly in 2019.
+
+# From Pierre Cashon (2020-10-20):
+# The summer time this year started on March 28 at 00:00.
+# https://wafa.ps/ar_page.aspx?id=GveQNZa872839351758aGveQNZ
+# http://www.palestinecabinet.gov.ps/portal/meeting/details/50284
+# The winter time in 2015 started on October 23 at 01:00.
+# https://wafa.ps/ar_page.aspx?id=CgpCdYa670694628582aCgpCdY
+# http://www.palestinecabinet.gov.ps/portal/meeting/details/27583
 #
-# From Tim Parenti (2016-10-19):
-# Predict fall transitions on October's last Saturday at 01:00 from now on.
+# From Paul Eggert (2019-04-10):
+# For now, guess spring-ahead transitions are at 00:00 on the Saturday
+# preceding March's last Sunday (i.e., Sat>=24).
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule EgyptAsia	1957	only	-	May	10	0:00	1:00	S
 Rule EgyptAsia	1957	1958	-	Oct	 1	0:00	0	-
 Rule EgyptAsia	1958	only	-	May	 1	0:00	1:00	S
@@ -3239,10 +3270,10 @@ Rule Palestine	2004	only	-	Oct	 1	1:00	0	-
 Rule Palestine	2005	only	-	Oct	 4	2:00	0	-
 Rule Palestine	2006	2007	-	Apr	 1	0:00	1:00	S
 Rule Palestine	2006	only	-	Sep	22	0:00	0	-
-Rule Palestine	2007	only	-	Sep	Thu>=8	2:00	0	-
+Rule Palestine	2007	only	-	Sep	13	2:00	0	-
 Rule Palestine	2008	2009	-	Mar	lastFri	0:00	1:00	S
 Rule Palestine	2008	only	-	Sep	 1	0:00	0	-
-Rule Palestine	2009	only	-	Sep	Fri>=1	1:00	0	-
+Rule Palestine	2009	only	-	Sep	 4	1:00	0	-
 Rule Palestine	2010	only	-	Mar	26	0:00	1:00	S
 Rule Palestine	2010	only	-	Aug	11	0:00	0	-
 Rule Palestine	2011	only	-	Apr	 1	0:01	1:00	S
@@ -3251,12 +3282,16 @@ Rule Palestine	2011	only	-	Aug	30	0:00	1:00	S
 Rule Palestine	2011	only	-	Sep	30	0:00	0	-
 Rule Palestine	2012	2014	-	Mar	lastThu	24:00	1:00	S
 Rule Palestine	2012	only	-	Sep	21	1:00	0	-
-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	2013	only	-	Sep	27	0:00	0	-
+Rule Palestine	2014	only	-	Oct	24	0:00	0	-
+Rule Palestine	2015	only	-	Mar	28	0:00	1:00	S
+Rule Palestine	2015	only	-	Oct	23	1:00	0	-
 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
+Rule Palestine	2016	2018	-	Oct	Sat>=24	1:00	0	-
+Rule Palestine	2019	only	-	Mar	29	0:00	1:00	S
+Rule Palestine	2019	only	-	Oct	Sat>=24	0:00	0	-
+Rule Palestine	2020	max	-	Mar	Sat>=24	0:00	1:00	S
+Rule Palestine	2020	max	-	Oct	Sat>=24	1:00	0	-
 
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Asia/Gaza	2:17:52	-	LMT	1900 Oct
@@ -3325,7 +3360,7 @@ Zone	Asia/Hebron	2:20:23	-	LMT	1900 Oct
 # influence of the sources.  There is no current abbreviation for DST,
 # so use "PDT", the usual American style.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Phil	1936	only	-	Nov	1	0:00	1:00	D
 Rule	Phil	1937	only	-	Feb	1	0:00	0	S
 Rule	Phil	1954	only	-	Apr	12	0:00	1:00	D
@@ -3473,7 +3508,7 @@ Zone	Asia/Colombo	5:19:24 -	LMT	1880
 			5:30	-	+0530
 
 # Syria
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Syria	1920	1923	-	Apr	Sun>=15	2:00	1:00	S
 Rule	Syria	1920	1923	-	Oct	Sun>=1	2:00	0	-
 Rule	Syria	1962	only	-	Apr	29	2:00	1:00	S
diff --git a/tz/australasia b/tz/australasia
index ac44c04..aa7ab7f 100644
--- a/tz/australasia
+++ b/tz/australasia
@@ -13,7 +13,7 @@
 
 # Please see the notes below for the controversy about "EST" versus "AEST" etc.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Aus	1917	only	-	Jan	 1	0:01	1:00	D
 Rule	Aus	1917	only	-	Mar	25	2:00	0	S
 Rule	Aus	1942	only	-	Jan	 1	2:00	1:00	D
@@ -32,7 +32,7 @@ Zone Australia/Darwin	 8:43:20 -	LMT	1895 Feb
 			 9:30	Aus	AC%sT
 # Western Australia
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	AW	1974	only	-	Oct	lastSun	2:00s	1:00	D
 Rule	AW	1975	only	-	Mar	Sun>=1	2:00s	0	S
 Rule	AW	1983	only	-	Oct	lastSun	2:00s	1:00	D
@@ -70,7 +70,7 @@ Zone Australia/Eucla	 8:35:28 -	LMT	1895 Dec
 # applies to all of the Whitsundays.
 # http://www.australia.gov.au/about-australia/australian-story/austn-islands
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	AQ	1971	only	-	Oct	lastSun	2:00s	1:00	D
 Rule	AQ	1972	only	-	Feb	lastSun	2:00s	0	S
 Rule	AQ	1989	1991	-	Oct	lastSun	2:00s	1:00	D
@@ -86,7 +86,7 @@ Zone Australia/Lindeman  9:55:56 -	LMT	1895
 			10:00	Holiday	AE%sT
 
 # South Australia
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	AS	1971	1985	-	Oct	lastSun	2:00s	1:00	D
 Rule	AS	1986	only	-	Oct	19	2:00s	1:00	D
 Rule	AS	1987	2007	-	Oct	lastSun	2:00s	1:00	D
@@ -114,7 +114,7 @@ Zone Australia/Adelaide	9:14:20 -	LMT	1895 Feb
 # http://www.bom.gov.au/climate/averages/tables/dst_times.shtml
 # says King Island didn't observe DST from WWII until late 1971.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	AT	1967	only	-	Oct	Sun>=1	2:00s	1:00	D
 Rule	AT	1968	only	-	Mar	lastSun	2:00s	0	S
 Rule	AT	1968	1985	-	Oct	lastSun	2:00s	1:00	D
@@ -147,7 +147,7 @@ Zone Australia/Currie	9:35:28	-	LMT	1895 Sep
 			10:00	AT	AE%sT
 
 # Victoria
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	AV	1971	1985	-	Oct	lastSun	2:00s	1:00	D
 Rule	AV	1972	only	-	Feb	lastSun	2:00s	0	S
 Rule	AV	1973	1985	-	Mar	Sun>=1	2:00s	0	S
@@ -168,7 +168,7 @@ Zone Australia/Melbourne 9:39:52 -	LMT	1895 Feb
 			10:00	AV	AE%sT
 
 # New South Wales
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	AN	1971	1985	-	Oct	lastSun	2:00s	1:00	D
 Rule	AN	1972	only	-	Feb	27	2:00s	0	S
 Rule	AN	1973	1981	-	Mar	Sun>=1	2:00s	0	S
@@ -197,7 +197,7 @@ Zone Australia/Broken_Hill 9:25:48 -	LMT	1895 Feb
 			9:30	AS	AC%sT
 
 # Lord Howe Island
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	LH	1981	1984	-	Oct	lastSun	2:00	1:00	-
 Rule	LH	1982	1985	-	Mar	Sun>=1	2:00	0	-
 Rule	LH	1985	only	-	Oct	lastSun	2:00	0:30	-
@@ -252,8 +252,9 @@ Zone Antarctica/Macquarie 0	-	-00	1899 Nov
 			10:00	Aus	AE%sT	1919 Apr  1  0:00s
 			0	-	-00	1948 Mar 25
 			10:00	Aus	AE%sT	1967
-			10:00	AT	AE%sT	2010 Apr  4  3:00
-			11:00	-	+11
+			10:00	AT	AE%sT	2010
+			10:00	1:00	AEDT	2011
+			10:00	AT	AE%sT
 
 # Christmas
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
@@ -380,7 +381,20 @@ Zone	Indian/Cocos	6:27:40	-	LMT	1900
 # From Michael Deckers (2019-08-06):
 # https://www.laws.gov.fj/LawsAsMade/downloadfile/848
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# From Raymond Kumar (2020-10-08):
+# [DST in Fiji] is from December 20th 2020, till 17th January 2021.
+# From Alan Mintz (2020-10-08):
+# https://www.laws.gov.fj/LawsAsMade/GetFile/1071
+# From Tim Parenti (2020-10-08):
+# https://www.fijivillage.com/news/Daylight-saving-from-Dec-20th-this-year-to-Jan-17th-2021-8rf4x5/
+# "Minister for Employment, Parveen Bala says they had never thought of
+# stopping daylight saving. He says it was just to decide on when it should
+# start and end.  Bala says it is a short period..."
+# Since the end date is still in line with our ongoing predictions, assume for
+# now that the later-than-usual start date is a one-time departure from the
+# recent second Sunday in November pattern.
+
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Fiji	1998	1999	-	Nov	Sun>=1	2:00	1:00	-
 Rule	Fiji	1999	2000	-	Feb	lastSun	3:00	0	-
 Rule	Fiji	2009	only	-	Nov	29	2:00	1:00	-
@@ -391,7 +405,9 @@ Rule	Fiji	2012	2013	-	Jan	Sun>=18	3:00	0	-
 Rule	Fiji	2014	only	-	Jan	Sun>=18	2:00	0	-
 Rule	Fiji	2014	2018	-	Nov	Sun>=1	2:00	1:00	-
 Rule	Fiji	2015	max	-	Jan	Sun>=12	3:00	0	-
-Rule	Fiji	2019	max	-	Nov	Sun>=8	2:00	1:00	-
+Rule	Fiji	2019	only	-	Nov	Sun>=8	2:00	1:00	-
+Rule	Fiji	2020	only	-	Dec	20	2:00	1:00	-
+Rule	Fiji	2021	max	-	Nov	Sun>=8	2:00	1:00	-
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
 Zone	Pacific/Fiji	11:55:44 -	LMT	1915 Oct 26 # Suva
 			12:00	Fiji	+12/+13
@@ -409,7 +425,7 @@ Zone	Pacific/Tahiti	 -9:58:16 -	LMT	1912 Oct # Papeete
 
 # Guam
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # http://guamlegislature.com/Public_Laws_5th/PL05-025.pdf
 # http://documents.guam.gov/wp-content/uploads/E.O.-59-7-Guam-Daylight-Savings-Time-May-6-1959.pdf
 Rule	Guam	1959	only	-	Jun	27	2:00	1:00	D
@@ -520,7 +536,7 @@ Zone	Pacific/Nauru	11:07:40 -	LMT	1921 Jan 15 # Uaobe
 			12:00	-	+12
 
 # New Caledonia
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	NC	1977	1978	-	Dec	Sun>=1	0:00	1:00	-
 Rule	NC	1978	1979	-	Feb	27	0:00	0	-
 Rule	NC	1996	only	-	Dec	 1	2:00s	1:00	-
@@ -535,7 +551,7 @@ Zone	Pacific/Noumea	11:05:48 -	LMT	1912 Jan 13 # Nouméa
 
 # New Zealand
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	NZ	1927	only	-	Nov	 6	2:00	1:00	S
 Rule	NZ	1928	only	-	Mar	 4	2:00	0	M
 Rule	NZ	1928	1933	-	Oct	Sun>=8	2:00	0:30	S
@@ -587,7 +603,7 @@ Link Pacific/Auckland Antarctica/McMurdo
 
 # Cook Is
 # From Shanks & Pottenger:
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Cook	1978	only	-	Nov	12	0:00	0:30	-
 Rule	Cook	1979	1991	-	Mar	Sun>=1	0:00	0	-
 Rule	Cook	1979	1990	-	Oct	lastSun	0:00	0:30	-
@@ -732,7 +748,7 @@ Link Pacific/Pago_Pago Pacific/Midway # in US minor outlying islands
 # That web page currently lists transitions for 2012/3 and 2013/4.
 # Assume the pattern instituted in 2012 will continue indefinitely.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	WS	2010	only	-	Sep	lastSun	0:00	1	-
 Rule	WS	2011	only	-	Apr	Sat>=1	4:00	0	-
 Rule	WS	2011	only	-	Sep	lastSat	3:00	1	-
@@ -776,7 +792,7 @@ Zone	Pacific/Fakaofo	-11:24:56 -	LMT	1901
 			13:00	-	+13
 
 # Tonga
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Tonga	1999	only	-	Oct	 7	2:00s	1:00	-
 Rule	Tonga	2000	only	-	Mar	19	2:00s	0	-
 Rule	Tonga	2000	2001	-	Nov	Sun>=1	2:00	1:00	-
@@ -857,7 +873,7 @@ Zone	Pacific/Wake	11:06:28 -	LMT	1901
 
 
 # Vanuatu
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Vanuatu	1983	only	-	Sep	25	0:00	1:00	-
 Rule	Vanuatu	1984	1991	-	Mar	Sun>=23	0:00	0	-
 Rule	Vanuatu	1984	only	-	Oct	23	0:00	1:00	-
diff --git a/tz/backzone b/tz/backzone
index 91fa21d..563aff6 100644
--- a/tz/backzone
+++ b/tz/backzone
@@ -150,7 +150,7 @@ Zone	Africa/Douala	0:38:48	-	LMT	1912
 # Whitman gives Mar 31 - Aug 31 for 1931 on.
 # The International Hydrographic Bulletin, 1932-33, p 63 says that
 # Sierra Leone would advance its clocks by 20 minutes on 1933-10-01.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	SL	1935	1942	-	Jun	 1	0:00	0:40	-0020
 Rule	SL	1935	1942	-	Oct	 1	0:00	0	-01
 Rule	SL	1957	1962	-	Jun	 1	0:00	1:00	+01
@@ -351,7 +351,7 @@ Zone America/Guadeloupe	-4:06:08 -	LMT	1911 Jun  8 # Pointe-à-Pitre
 # Pottenger data.  The post-1970 entries have been corrected, but the
 # pre-1970 entries are unchecked and probably have errors.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Mont	1917	only	-	Mar	25	2:00	1:00	D
 Rule	Mont	1917	only	-	Apr	24	0:00	0	S
 Rule	Mont	1919	only	-	Mar	31	2:30	1:00	D
@@ -459,7 +459,34 @@ Zone	Asia/Aden	2:59:54	-	LMT	1950
 			3:00	-	+03
 
 # Bahrain
-Zone	Asia/Bahrain	3:22:20 -	LMT	1920     # Manamah
+#
+# From Paul Eggert (2020-07-23):
+# Most of this data comes from:
+# Stewart A. Why Gulf Standard Time is far from standard: the fascinating story
+# behind the time zone's invention. The National (Abu Dhabi). 2020-07-22.
+# https://www.thenational.ae/arts-culture/why-gulf-standard-time-is-far-from-standard-the-fascinating-story-behind-the-time-zone-s-invention-1.1052589
+# Stewart writes that before 1941 some companies in Bahrain were at +0330 and
+# others at +0323.  Reginald George Alban, a British political agent based in
+# Manama, worked to standardize this, and from 1941-07-20 Bahrain was at
+# +0330.  However, BOAC asked that clocks be moved to gain more light at day's
+# end, so Bahrain switched to +04 on 1944-01-01.
+#
+# Re the 1941 transition, Stewart privately sent me this citation:
+# "File 16/53 Enquiries Re: Calculation of Local Time", British Library: India
+# Office Records and Private Papers, IOR/R/15/2/1564, in Qatar Digital Library
+# https://www.qdl.qa/archive/81055/vdc_100000000282.0x00012b
+# It says there was no real standard in Bahrain before 1941-07-20.
+# +0330 was used by steamers of the British India Co, by Petroleum Concessions
+# and by Cable & Wireless; +0323 was used by the Eastern Bank Ltd, BOAC, and
+# Bahrein Petroleum (Bapco), and California Arabian Standard Oil Co (Casoc)
+# adopted DST effective 1941-05-24.  Alban suggested adopting DST, R.B. Coomb
+# of C&W countersuggested +0330, and although C.A. Rodstrom of Casoc (formerly
+# of Bapco) stated that Bahrain had formerly used +0330 before Bapco arrived
+# but Bapco switched to +0323 because of "constant confusion", the consensus
+# was +0330.  The government adopted +0330 in 1941-07-20 and companies seem to
+# have switched by 08-01.  No time of day was given for the 1940s transitions.
+Zone	Asia/Bahrain	3:22:20 -	LMT	1941 Jul 20  # Manamah
+			3:30	-	+0330	1944 Jan  1
 			4:00	-	+04	1972 Jun
 			3:00	-	+03
 
diff --git a/tz/date.1 b/tz/date.1
index 6e79cc1..432cab1 100644
--- a/tz/date.1
+++ b/tz/date.1
@@ -27,7 +27,9 @@ date \- show and set date and time
 .de q
 \\$3\*(lq\\$1\*(rq\\$2
 ..
-.I Date
+The
+.B date
+command
 without arguments writes the date and time to the standard output in
 the form
 .ce 1
diff --git a/tz/date.c b/tz/date.c
index 2cc533f..ef4e4d4 100644
--- a/tz/date.c
+++ b/tz/date.c
@@ -59,8 +59,7 @@ static _Noreturn void	usage(void);
 int
 main(const int argc, char *argv[])
 {
-	register const char *	format;
-	register const char *	cp;
+	register const char *	format = "+%+";
 	register int		ch;
 	register bool		rflag = false;
 	time_t			t;
@@ -77,7 +76,6 @@ main(const int argc, char *argv[])
 	textdomain(TZ_DOMAIN);
 #endif /* HAVE_GETTEXT */
 	t = time(NULL);
-	format = NULL;
 	while ((ch = getopt(argc, argv, "ucr:")) != EOF && ch != -1) {
 		switch (ch) {
 		default:
@@ -108,20 +106,17 @@ main(const int argc, char *argv[])
 			break;
 		}
 	}
-	while (optind < argc) {
-		cp = argv[optind++];
-		if (*cp == '+')
-			if (format == NULL)
-				format = cp + 1;
-			else {
-				fprintf(stderr,
-_("date: error: multiple formats in command line\n"));
-				usage();
-			}
-		else {
-		  fprintf(stderr, _("date: unknown operand: %s\n"), cp);
-		  usage();
-		}
+	if (optind < argc) {
+	  if (argc - optind != 1) {
+	    fprintf(stderr,
+		    _("date: error: multiple operands in command line\n"));
+	    usage();
+	  }
+	  format = argv[optind];
+	  if (*format != '+') {
+	    fprintf(stderr, _("date: unknown operand: %s\n"), format);
+	    usage();
+	  }
 	}
 
 	display(format, t);
@@ -186,7 +181,7 @@ display(char const *format, time_t now)
 		errensure();
 		return;
 	}
-	timeout(stdout, format ? format : "%+", tmp);
+	timeout(stdout, format, tmp);
 	putchar('\n');
 	fflush(stdout);
 	fflush(stderr);
@@ -207,8 +202,6 @@ timeout(FILE *fp, char const *format, struct tm const *tmp)
 	size_t	size;
 	struct tm tm;
 
-	if (*format == '\0')
-		return;
 	if (!tmp) {
 		fprintf(stderr, _("date: error: time out of range\n"));
 		errensure();
@@ -225,13 +218,12 @@ timeout(FILE *fp, char const *format, struct tm const *tmp)
 			errensure();
 			exit(retval);
 		}
-		cp[0] = '\1';
 		result = strftime(cp, size, format, tmp);
-		if (result != 0 || cp[0] == '\0')
+		if (result != 0)
 			break;
 		size += INCR;
 		cp = realloc(cp, size);
 	}
-	fwrite(cp, 1, result, fp);
+	fwrite(cp + 1, 1, result - 1, fp);
 	free(cp);
 }
diff --git a/tz/europe b/tz/europe
index 5593c60..ea23736 100644
--- a/tz/europe
+++ b/tz/europe
@@ -388,7 +388,7 @@
 # http://www.irishstatutebook.ie/eli/1926/sro/919/made/en/print
 # http://www.irishstatutebook.ie/eli/1947/sro/71/made/en/print
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # Summer Time Act, 1916
 Rule	GB-Eire	1916	only	-	May	21	2:00s	1:00	BST
 Rule	GB-Eire	1916	only	-	Oct	 1	2:00s	0	GMT
@@ -529,7 +529,7 @@ Link	Europe/London	Europe/Isle_of_Man
 # The following is like GB-Eire and EU, except with standard time in
 # summer and negative daylight saving time in winter.  It is for when
 # negative SAVE values are used.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Eire	1971	only	-	Oct	31	 2:00u	-1:00	-
 Rule	Eire	1972	1980	-	Mar	Sun>=16	 2:00u	0	-
 Rule	Eire	1972	1980	-	Oct	Sun>=23	 2:00u	-1:00	-
@@ -566,7 +566,7 @@ Zone	Europe/Dublin	-0:25:00 -	LMT	1880 Aug  2
 # predecessor organization, the European Communities.
 # For brevity they are called "EU rules" elsewhere in this file.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	EU	1977	1980	-	Apr	Sun>=1	 1:00u	1:00	S
 Rule	EU	1977	only	-	Sep	lastSun	 1:00u	0	-
 Rule	EU	1978	only	-	Oct	 1	 1:00u	0	-
@@ -606,13 +606,13 @@ Rule	C-Eur	1944	only	-	Oct	 2	 2:00s	0	-
 # corrected in version 2008d). The circumstantial evidence is simply the
 # tz database itself, as seen below:
 #
-# Zone Europe/Paris 0:09:21 - LMT 1891 Mar 15  0:01
+# Zone Europe/Paris ...
 #    0:00 France WE%sT 1945 Sep 16  3:00
 #
-# Zone Europe/Monaco 0:29:32 - LMT 1891 Mar 15
+# Zone Europe/Monaco ...
 #    0:00 France WE%sT 1945 Sep 16  3:00
 #
-# Zone Europe/Belgrade 1:22:00 - LMT 1884
+# Zone Europe/Belgrade ...
 #    1:00 1:00 CEST 1945 Sep 16  2:00s
 #
 # Rule France 1945 only - Sep 16  3:00 0 -
@@ -658,7 +658,7 @@ Rule	E-Eur	1996	max	-	Oct	lastSun	 0:00	0	-
 #
 # The 1917-1921 decree URLs are from Alexander Belopolsky (2016-08-23).
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Russia	1917	only	-	Jul	 1	23:00	1:00	MST  # Moscow Summer Time
 #
 # Decree No. 142 (1917-12-22) http://istmat.info/node/28137
@@ -772,7 +772,7 @@ Zone	EET		2:00	EU	EE%sT
 
 
 # Albania
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Albania	1940	only	-	Jun	16	0:00	1:00	S
 Rule	Albania	1942	only	-	Nov	 2	3:00	0	-
 Rule	Albania	1943	only	-	Mar	29	2:00	1:00	S
@@ -826,7 +826,7 @@ Zone	Europe/Andorra	0:06:04 -	LMT	1901
 # In 1946 the end of DST was on Monday, 7 October 1946, at 3:00 am.
 # Shanks had this right.  Source: Die Weltpresse, 5. Oktober 1946, page 5.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Austria	1920	only	-	Apr	 5	2:00s	1:00	S
 Rule	Austria	1920	only	-	Sep	13	2:00s	0	-
 Rule	Austria	1946	only	-	Apr	14	2:00s	1:00	S
@@ -913,7 +913,7 @@ Zone	Europe/Minsk	1:50:16 -	LMT	1880
 # The 1918 rules are listed for completeness; they apply to unoccupied Belgium.
 # Assume Brussels switched to WET in 1918 when the armistice took effect.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Belgium	1918	only	-	Mar	 9	 0:00s	1:00	S
 Rule	Belgium	1918	1919	-	Oct	Sat>=1	23:00s	0	-
 Rule	Belgium	1919	only	-	Mar	 1	23:00s	1:00	S
@@ -973,7 +973,7 @@ Zone	Europe/Brussels	0:17:30 -	LMT	1880
 # EET -> EETDST is in 03:00 Local time in last Sunday of March ...
 # EETDST -> EET is in 04:00 Local time in last Sunday of October
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Bulg	1979	only	-	Mar	31	23:00	1:00	S
 Rule	Bulg	1979	only	-	Oct	 1	 1:00	0	-
 Rule	Bulg	1980	1982	-	Apr	Sat>=1	23:00	1:00	S
@@ -1005,7 +1005,7 @@ Zone	Europe/Sofia	1:33:16 -	LMT	1880
 # We know of no English-language name for historical Czech winter time;
 # abbreviate it as "GMT", as it happened to be GMT.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Czech	1945	only	-	Apr	Mon>=1	2:00s	1:00	S
 Rule	Czech	1945	only	-	Oct	 1	2:00s	0	-
 Rule	Czech	1946	only	-	May	 6	2:00s	1:00	S
@@ -1029,17 +1029,16 @@ Zone	Europe/Prague	0:57:44 -	LMT	1850
 # Denmark, Faroe Islands, and Greenland
 
 # From Jesper Nørgaard Welen (2005-04-26):
-# http://www.hum.aau.dk/~poe/tid/tine/DanskTid.htm says that the law
-# [introducing standard time] was in effect from 1894-01-01....
-# The page http://www.retsinfo.dk/_GETDOCI_/ACCN/A18930008330-REGL
+# the law [introducing standard time] was in effect from 1894-01-01....
+# The page https://www.retsinformation.dk/eli/lta/1893/83
 # confirms this, and states that the law was put forth 1893-03-29.
 #
 # The EU [actually, EEC and Euratom] treaty with effect from 1973:
-# http://www.retsinfo.dk/_GETDOCI_/ACCN/A19722110030-REGL
+# https://www.retsinformation.dk/eli/lta/1972/21100
 #
 # This provoked a new law from 1974 to make possible summer time changes
 # in subsequent decrees with the law
-# http://www.retsinfo.dk/_GETDOCI_/ACCN/A19740022330-REGL
+# https://www.retsinformation.dk/eli/lta/1974/223
 #
 # It seems however that no decree was set forward until 1980.  I have
 # not found any decree, but in another related law, the effecting DST
@@ -1051,7 +1050,7 @@ Zone	Europe/Prague	0:57:44 -	LMT	1850
 # The law is about the management of the extra hour, concerning
 # working hours reported and effect on obligatory-rest rules (which
 # was suspended on that night):
-# http://www.retsinfo.dk/_GETDOCI_/ACCN/C19801120554-REGL
+# https://web.archive.org/web/20140104053304/https://www.retsinformation.dk/Forms/R0710.aspx?id=60267
 
 # From Jesper Nørgaard Welen (2005-06-11):
 # The Herning Folkeblad (1980-09-26) reported that the night between
@@ -1061,7 +1060,7 @@ Zone	Europe/Prague	0:57:44 -	LMT	1850
 # Hence the "02:00" of the 1980 law refers to standard time, not
 # wall-clock time, and so the EU rules were in effect in 1980.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Denmark	1916	only	-	May	14	23:00	1:00	S
 Rule	Denmark	1916	only	-	Sep	30	23:00	0	-
 Rule	Denmark	1940	only	-	May	15	 0:00	1:00	S
@@ -1163,7 +1162,7 @@ Zone Atlantic/Faroe	-0:27:04 -	LMT	1908 Jan 11 # Tórshavn
 # http://naalakkersuisut.gl/~/media/Nanoq/Files/Attached%20Files/Engelske-tekster/Legislation/Executive%20Order%20National%20Park.rtf
 # It is their only National Park.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Thule	1991	1992	-	Mar	lastSun	2:00	1:00	D
 Rule	Thule	1991	1992	-	Sep	lastSun	2:00	0	S
 Rule	Thule	1993	2006	-	Apr	Sun>=1	2:00	1:00	D
@@ -1294,7 +1293,7 @@ Zone	Europe/Tallinn	1:39:00	-	LMT	1880
 # From Paul Eggert (2014-06-14):
 # Go with Oja over Shanks.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Finland	1942	only	-	Apr	2	24:00	1:00	S
 Rule	Finland	1942	only	-	Oct	4	1:00	0	-
 Rule	Finland	1981	1982	-	Mar	lastSun	2:00	1:00	S
@@ -1326,10 +1325,58 @@ Link	Europe/Helsinki	Europe/Mariehamn
 # Françoise Gauquelin, Problèmes de l'heure résolus en astrologie,
 # Guy Trédaniel, Paris 1987
 
+# From Michael Deckers (2020-06-11):
+# the law of 1891 <https://gallica.bnf.fr/ark:/12148/bpt6k64415343.texteImage>
+# was published on 1891-03-15, so it could only take force on 1891-03-16.
+
+# From Michael Deckers (2020-06-10):
+# Le Gaulois, 1911-03-11, page 1/6, online at
+# https://www.retronews.fr/societe/echo-de-presse/2018/01/29/1911-change-lheure-de-paris
+# ... [ Instantly, all pressure driven clock dials halted...  Nine minutes and
+#       twenty-one seconds later the hands resumed their circular motion. ]
+# There are also precise reports about how the change was prepared in train
+# stations: all the publicly visible clocks stopped at midnight railway time
+# (or were covered), only the chief of service had a watch, labeled
+# "Heure ancienne", that he kept running until it reached 00:04:21, when
+# he announced "Heure nouvelle".  See the "Le Petit Journal 1911-03-11".
+# https://gallica.bnf.fr/ark:/12148/bpt6k6192911/f1.item.zoom
+#
+# From Michael Deckers (2020-06-12):
+# That "all French clocks stopped" for 00:09:21 is a misreading of French
+# newspapers; this sort of adjustment applies only to certain
+# remote-controlled clocks ("pendules pneumatiques", of which there existed
+# perhaps a dozen in Paris, and which simply could not be set back remotely),
+# but not to all the clocks in all French towns and villages.  For instance,
+# the following story in the "Courrier de Saône-et-Loire" 1911-03-11, page 2:
+# only works if legal time was stepped back (was not monotone): ...
+#   [One can observe that children who had been born at midnight less 5
+#    minutes and who had died at midnight of the old time, would turn out to
+#    be dead before being born, time having been set back and having
+#    suppressed 9 minutes and 25 seconds of their existence, that is, more
+#    than they could spend.]
+#
+# From Paul Eggert (2020-06-12):
+# French time in railway stations was legally five minutes behind civil time,
+# which explains why railway "old time" ran to 00:04:21 instead of to 00:09:21.
+# The law's text (which Michael Deckers noted is at
+# <https://gallica.bnf.fr/ark:/12148/bpt6k2022333z/f2>) says only that
+# at 1911-03-11 00:00 legal time was that of Paris mean time delayed by
+# nine minutes and twenty-one seconds, and does not say how the
+# transition from Paris mean time was to occur.
+#
+# tzdb has no way to represent stopped clocks.  As the railway practice
+# was to keep a watch running on "old time" to decide when to restart
+# the other clocks, this could be modeled as a transition for "old time" at
+# 00:09:21.  However, since the law was ambiguous and clocks outside railway
+# stations were probably done haphazardly with the popular impression being
+# that the transition was done at 00:00 "old time", simply leave the time
+# blank; this causes zic to default to 00:00 "old time" which is good enough.
+# Do something similar for the 1891-03-16 transition.  There are similar
+# problems in Algiers, Monaco and Tunis.
 
 #
 # Shank & Pottenger seem to use '24:00' ambiguously; resolve it with Whitman.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	France	1916	only	-	Jun	14	23:00s	1:00	S
 Rule	France	1916	1919	-	Oct	Sun>=1	23:00s	0	-
 Rule	France	1917	only	-	Mar	24	23:00s	1:00	S
@@ -1389,13 +1436,11 @@ Rule	France	1945	only	-	Sep	16	 3:00	0	-
 # go with Excoffier's 28/3/76 0hUT and 25/9/76 23hUT.
 Rule	France	1976	only	-	Mar	28	 1:00	1:00	S
 Rule	France	1976	only	-	Sep	26	 1:00	0	-
-# Shanks & Pottenger give 0:09:20 for Paris Mean Time, and Whitman 0:09:05,
-# 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
+# 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		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
+Zone	Europe/Paris	0:09:21 -	LMT	1891 Mar 16
+			0:09:21	-	PMT	1911 Mar 11 # Paris Mean Time
 # Shanks & Pottenger give 1940 Jun 14 0:00; go with Excoffier and Le Corre.
 			0:00	France	WE%sT	1940 Jun 14 23:00
 # Le Corre says Paris stuck with occupied-France time after the liberation;
@@ -1424,7 +1469,7 @@ Zone	Europe/Paris	0:09:21 -	LMT	1891 Mar 15  0:01
 # this was equivalent to UT +03, not +04.
 
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Germany	1946	only	-	Apr	14	2:00s	1:00	S
 Rule	Germany	1946	only	-	Oct	 7	2:00s	0	-
 Rule	Germany	1947	1949	-	Oct	Sun>=1	2:00s	0	-
@@ -1476,7 +1521,7 @@ Zone Europe/Gibraltar	-0:21:24 -	LMT	1880 Aug  2  0:00s
 			1:00	EU	CE%sT
 
 # Greece
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # Whitman gives 1932 Jul 5 - Nov 1; go with Shanks & Pottenger.
 Rule	Greece	1932	only	-	Jul	 7	0:00	1:00	S
 Rule	Greece	1932	only	-	Sep	 1	0:00	0	-
@@ -1511,38 +1556,73 @@ Zone	Europe/Athens	1:34:52 -	LMT	1895 Sep 14
 			2:00	EU	EE%sT
 
 # Hungary
-# From Paul Eggert (2014-07-15):
-# Dates for 1916-1945 are taken from:
-# Oross A. Jelen a múlt jövője: a nyári időszámítás Magyarországon 1916-1945.
-# National Archives of Hungary (2012-10-29).
-# http://mnl.gov.hu/a_het_dokumentuma/a_nyari_idoszamitas_magyarorszagon_19161945.html
-# This source does not always give times, which are taken from Shanks
-# & Pottenger (which disagree about the dates).
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	Hungary	1918	only	-	Apr	 1	 3:00	1:00	S
-Rule	Hungary	1918	only	-	Sep	16	 3:00	0	-
-Rule	Hungary	1919	only	-	Apr	15	 3:00	1:00	S
-Rule	Hungary	1919	only	-	Nov	24	 3:00	0	-
+
+# From Michael Deckers (2020-06-09):
+# an Austrian encyclopedia of railroads of 1913, online at
+# http://www.zeno.org/Roell-1912/A/Eisenbahnzeit
+# says that the switch [to CET] happened on 1890-11-01.
+
+# From Géza Nyáry (2020-06-07):
+# Data for 1918-1983 are based on the archive database of Library Hungaricana.
+# The dates are collected from original, scanned governmental orders,
+# bulletins, instructions and public press.
+# [See URLs below.]
+
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
+# https://library.hungaricana.hu/hu/view/OGYK_RT_1918/?pg=238
+# https://library.hungaricana.hu/hu/view/OGYK_RT_1919/?pg=808
+# https://library.hungaricana.hu/hu/view/OGYK_RT_1920/?pg=201
+Rule	Hungary	1918	1919	-	Apr	15	 2:00	1:00	S
+Rule	Hungary	1918	1920	-	Sep	Mon>=15	 3:00	0	-
+Rule	Hungary	1920	only	-	Apr	 5	 2:00	1:00	S
+# https://library.hungaricana.hu/hu/view/OGYK_RT_1945/?pg=882
 Rule	Hungary	1945	only	-	May	 1	23:00	1:00	S
-Rule	Hungary	1945	only	-	Nov	 1	 0:00	0	-
+Rule	Hungary	1945	only	-	Nov	 1	 1:00	0	-
+# https://library.hungaricana.hu/hu/view/Delmagyarorszag_1946_03/?pg=49
 Rule	Hungary	1946	only	-	Mar	31	 2:00s	1:00	S
-Rule	Hungary	1946	1949	-	Oct	Sun>=1	 2:00s	0	-
+# https://library.hungaricana.hu/hu/view/Delmagyarorszag_1946_09/?pg=54
+Rule	Hungary	1946	only	-	Oct	 7	 2:00	0	-
+# https://library.hungaricana.hu/hu/view/KulfBelfHirek_1947_04_1__001-123/?pg=90
+# https://library.hungaricana.hu/hu/view/DunantuliNaplo_1947_09/?pg=128
+# https://library.hungaricana.hu/hu/view/KulfBelfHirek_1948_03_3__001-123/?pg=304
+# https://library.hungaricana.hu/hu/view/Zala_1948_09/?pg=64
+# https://library.hungaricana.hu/hu/view/SatoraljaujhelyiLeveltar_ZempleniNepujsag_1948/?pg=53
+# https://library.hungaricana.hu/hu/view/SatoraljaujhelyiLeveltar_ZempleniNepujsag_1948/?pg=160
+# https://library.hungaricana.hu/hu/view/UjSzo_1949_01-04/?pg=102
+# https://library.hungaricana.hu/hu/view/KeletMagyarorszag_1949_03/?pg=96
+# https://library.hungaricana.hu/hu/view/Delmagyarorszag_1949_09/?pg=94
 Rule	Hungary	1947	1949	-	Apr	Sun>=4	 2:00s	1:00	S
-Rule	Hungary	1950	only	-	Apr	17	 2:00s	1:00	S
-Rule	Hungary	1950	only	-	Oct	23	 2:00s	0	-
-Rule	Hungary	1954	1955	-	May	23	 0:00	1:00	S
-Rule	Hungary	1954	1955	-	Oct	 3	 0:00	0	-
-Rule	Hungary	1956	only	-	Jun	Sun>=1	 0:00	1:00	S
-Rule	Hungary	1956	only	-	Sep	lastSun	 0:00	0	-
-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
+Rule	Hungary	1947	1949	-	Oct	Sun>=1	 2:00s	0	-
+# https://library.hungaricana.hu/hu/view/DTT_KOZL_TanacsokKozlonye_1954/?pg=513
+Rule	Hungary	1954	only	-	May	23	 0:00	1:00	S
+Rule	Hungary	1954	only	-	Oct	 3	 0:00	0	-
+# https://library.hungaricana.hu/hu/view/DTT_KOZL_TanacsokKozlonye_1955/?pg=398
+Rule	Hungary	1955	only	-	May	22	 2:00	1:00	S
+Rule	Hungary	1955	only	-	Oct	 2	 3:00	0	-
+# https://library.hungaricana.hu/hu/view/HevesMegyeiNepujsag_1956_06/?pg=0
+# https://library.hungaricana.hu/hu/view/EszakMagyarorszag_1956_06/?pg=6
+# https://library.hungaricana.hu/hu/view/SzolnokMegyeiNeplap_1957_04/?pg=120
+# https://library.hungaricana.hu/hu/view/PestMegyeiHirlap_1957_09/?pg=143
+Rule	Hungary	1956	1957	-	Jun	Sun>=1	 2:00	1:00	S
+Rule	Hungary	1956	1957	-	Sep	lastSun	 3:00	0	-
+# https://library.hungaricana.hu/hu/view/DTT_KOZL_TanacsokKozlonye_1980/?pg=189
+Rule	Hungary	1980	only	-	Apr	 6	 0:00	1:00	S
+Rule	Hungary	1980	only	-	Sep	28	 1:00	0	-
+# https://library.hungaricana.hu/hu/view/DTT_KOZL_TanacsokKozlonye_1980/?pg=1227
+# https://library.hungaricana.hu/hu/view/Delmagyarorszag_1981_01/?pg=79
+# https://library.hungaricana.hu/hu/view/DTT_KOZL_TanacsokKozlonye_1982/?pg=115
+# https://library.hungaricana.hu/hu/view/DTT_KOZL_TanacsokKozlonye_1983/?pg=85
+Rule	Hungary	1981	1983	-	Mar	lastSun	 0:00	1:00	S
+Rule	Hungary	1981	1983	-	Sep	lastSun	 1:00	0	-
+#
 # Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]
-Zone	Europe/Budapest	1:16:20 -	LMT	1890 Oct
+Zone	Europe/Budapest	1:16:20 -	LMT	1890 Nov  1
 			1:00	C-Eur	CE%sT	1918
-			1:00	Hungary	CE%sT	1941 Apr  8
+# https://library.hungaricana.hu/hu/view/OGYK_RT_1941/?pg=1204
+# https://library.hungaricana.hu/hu/view/OGYK_RT_1942/?pg=3955
+			1:00	Hungary	CE%sT	1941 Apr  7 23:00
 			1:00	C-Eur	CE%sT	1945
-			1:00	Hungary	CE%sT	1980 Sep 28  2:00s
+			1:00	Hungary	CE%sT	1984
 			1:00	EU	CE%sT
 
 # Iceland
@@ -1578,7 +1658,7 @@ Zone	Europe/Budapest	1:16:20 -	LMT	1890 Oct
 # The information below is taken from the 1988 Almanak; see
 # http://www.almanak.hi.is/klukkan.html
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Iceland	1917	1919	-	Feb	19	23:00	1:00	-
 Rule	Iceland	1917	only	-	Oct	21	 1:00	0	-
 Rule	Iceland	1918	1919	-	Nov	16	 1:00	0	-
@@ -1670,7 +1750,7 @@ Zone Atlantic/Reykjavik	-1:28	-	LMT	1908
 # to 1944-06-04; although Rome was an open city during this period, it
 # was effectively controlled by Germany.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Italy	1916	only	-	Jun	 3	24:00	1:00	S
 Rule	Italy	1916	1917	-	Sep	30	24:00	0	-
 Rule	Italy	1917	only	-	Mar	31	24:00	1:00	S
@@ -1780,7 +1860,7 @@ Link	Europe/Rome	Europe/San_Marino
 # urged Lithuania and Estonia to adopt a similar time policy, but it
 # appears that they will not do so....
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Latvia	1989	1996	-	Mar	lastSun	 2:00s	1:00	S
 Rule	Latvia	1989	1996	-	Sep	lastSun	 2:00s	0	-
 
@@ -1873,7 +1953,7 @@ Zone	Europe/Vilnius	1:41:16	-	LMT	1880
 # Luxembourg
 # Whitman disagrees with most of these dates in minor ways;
 # go with Shanks & Pottenger.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Lux	1916	only	-	May	14	23:00	1:00	S
 Rule	Lux	1916	only	-	Oct	 1	 1:00	0	-
 Rule	Lux	1917	only	-	Apr	28	23:00	1:00	S
@@ -1914,7 +1994,7 @@ Zone Europe/Luxembourg	0:24:36 -	LMT	1904 Jun
 # From Paul Eggert (2016-10-21):
 # Assume 1900-1972 was like Rome, overriding Shanks.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Malta	1973	only	-	Mar	31	0:00s	1:00	S
 Rule	Malta	1973	only	-	Sep	29	0:00s	0	-
 Rule	Malta	1974	only	-	Apr	21	0:00s	1:00	S
@@ -1987,7 +2067,7 @@ Zone	Europe/Malta	0:58:04 -	LMT	1893 Nov  2  0:00s # Valletta
 # says the 2014-03-30 spring-forward transition was at 02:00 local time.
 # Guess that since 1997 Moldova has switched one hour before the EU.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Moldova	1997	max	-	Mar	lastSun	 2:00	1:00	S
 Rule	Moldova	1997	max	-	Oct	lastSun	 3:00	0	-
 
@@ -2005,11 +2085,24 @@ Zone	Europe/Chisinau	1:55:20 -	LMT	1880
 			2:00	Moldova	EE%sT
 
 # Monaco
-# Shanks & Pottenger give 0:09:20 for Paris Mean Time; go with Howse's
-# more precise 0:09:21.
+#
+# From Michael Deckers (2020-06-12):
+# In the "Journal de Monaco" of 1892-05-24, online at
+# https://journaldemonaco.gouv.mc/var/jdm/storage/original/application/b1c67c12c5af11b41ea888fb048e4fe8.pdf
+# we read: ...
+#  [In virtue of a Sovereign Ordinance of the May 13 of the current [year],
+#   legal time in the Principality will be set to, from the date of June 1,
+#   1892 onwards, to the meridian of Paris, as in France.]
+# In the "Journal de Monaco" of 1911-03-28, online at
+# https://journaldemonaco.gouv.mc/var/jdm/storage/original/application/de74ffb7db53d4f599059fe8f0ed482a.pdf
+# we read an ordinance of 1911-03-16: ...
+#  [Legal time in the Principality will be set, from the date of promulgation
+#   of the present ordinance, to legal time in France....  Consequently, legal
+#   time will be retarded by 9 minutes and 21 seconds.]
+#
 # 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
+Zone	Europe/Monaco	0:29:32 -	LMT	1892 Jun  1
+			0:09:21	-	PMT	1911 Mar 29 # Paris Mean Time
 			0:00	France	WE%sT	1945 Sep 16  3:00
 			1:00	France	CE%sT	1977
 			1:00	EU	CE%sT
@@ -2057,7 +2150,7 @@ Zone	Europe/Monaco	0:29:32 -	LMT	1891 Mar 15
 # The data entries before 1945 are taken from
 # https://www.staff.science.uu.nl/~gent0113/wettijd/wettijd.htm
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Neth	1916	only	-	May	 1	0:00	1:00	NST	# Netherlands Summer Time
 Rule	Neth	1916	only	-	Oct	 1	0:00	0	AMT	# Amsterdam Mean Time
 Rule	Neth	1917	only	-	Apr	16	2:00s	1:00	NST
@@ -2094,7 +2187,7 @@ Zone Europe/Amsterdam	0:19:32 -	LMT	1835
 # Norway
 # http://met.no/met/met_lex/q_u/sommertid.html (2004-01) agrees with Shanks &
 # Pottenger.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Norway	1916	only	-	May	22	1:00	1:00	S
 Rule	Norway	1916	only	-	Sep	30	0:00	0	-
 Rule	Norway	1945	only	-	Apr	 2	2:00s	1:00	S
@@ -2163,7 +2256,7 @@ Link	Europe/Oslo	Arctic/Longyearbyen
 # The 1919 dates and times can be found in Tygodnik Urzędowy nr 1 (1919-03-20),
 # <http://www.wbc.poznan.pl/publication/32156> pp 1-2.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Poland	1918	1919	-	Sep	16	2:00s	0	-
 Rule	Poland	1919	only	-	Apr	15	2:00s	1:00	S
 Rule	Poland	1944	only	-	Apr	 3	2:00s	1:00	S
@@ -2234,7 +2327,7 @@ Zone	Europe/Warsaw	1:24:00 -	LMT	1880
 # Guess that the Azores changed to EU rules in 1992 (since that's when Portugal
 # harmonized with EU rules), and that they stayed +0:00 that winter.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # DSH writes that despite Decree 1,469 (1915), the change to the clocks was not
 # done every year, depending on what Spain did, because of railroad schedules.
 # Go with Shanks & Pottenger.
@@ -2347,7 +2440,7 @@ Zone Atlantic/Madeira	-1:07:36 -	LMT	1884        # Funchal
 # assume that Romania and Moldova switched to EU rules in 1997,
 # the same year as Bulgaria.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Romania	1932	only	-	May	21	 0:00s	1:00	S
 Rule	Romania	1932	1939	-	Oct	Sun>=1	 0:00s	0	-
 Rule	Romania	1933	1939	-	Apr	Sun>=2	 0:00s	1:00	S
@@ -3445,14 +3538,14 @@ Link Europe/Prague Europe/Bratislava
 # fallback transition from the next day's 00:59... to 00:00.
 
 # From Michael Deckers (2016-12-15):
-# The Royal Decree of 1900-06-26 quoted by Planesas, online at
+# The Royal Decree of 1900-07-26 quoted by Planesas, online at
 # https://www.boe.es/datos/pdfs/BOE//1900/209/A00383-00384.pdf
 # says in its article 5 (my translation):
 # These dispositions will enter into force beginning with the
 # instant at which, according to the time indicated in article 1,
 # the 1st day of January of 1901 will begin.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Spain	1918	only	-	Apr	15	23:00	1:00	S
 Rule	Spain	1918	1919	-	Oct	 6	24:00s	0	-
 Rule	Spain	1919	only	-	Apr	 6	23:00	1:00	S
@@ -3589,7 +3682,7 @@ Zone Europe/Stockholm	1:12:12 -	LMT	1879 Jan  1
 # By the end of the 18th century clocks and watches became commonplace
 # and their performance improved enormously.  Communities began to keep
 # mean time in preference to apparent time - Geneva from 1780 ....
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # From Whitman (who writes "Midnight?"):
 # Rule	Swiss	1940	only	-	Nov	 2	0:00	1:00	S
 # Rule	Swiss	1940	only	-	Dec	31	0:00	0	-
@@ -3676,7 +3769,7 @@ Zone Europe/Stockholm	1:12:12 -	LMT	1879 Jan  1
 # 1853-07-16, though it probably occurred at some other date in Zurich, and
 # legal civil time probably changed at still some other transition date.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -3825,7 +3918,7 @@ Zone	Europe/Zurich	0:34:08 -	LMT	1853 Jul 16 # See above comment.
 # Although Google Translate misfires on that source, it looks like
 # Turkey reversed last month's decision, and so will stay at +03.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Turkey	1916	only	-	May	 1	0:00	1:00	S
 Rule	Turkey	1916	only	-	Oct	 1	0:00	0	-
 Rule	Turkey	1920	only	-	Mar	28	0:00	1:00	S
@@ -3983,7 +4076,7 @@ Zone Europe/Kiev	2:02:04 -	LMT	1880
 			2:00	1:00	EEST	1991 Sep 29  3:00
 			2:00	E-Eur	EE%sT	1995
 			2:00	EU	EE%sT
-# Ruthenia used CET 1990/1991.
+# Transcarpathia used CET 1990/1991.
 # "Uzhhorod" is the transliteration of the Rusyn/Ukrainian pronunciation, but
 # "Uzhgorod" is more common in English.
 Zone Europe/Uzhgorod	1:29:12 -	LMT	1890 Oct
diff --git a/tz/leap-seconds.list b/tz/leap-seconds.list
index ac153da..e897a86 100644
--- a/tz/leap-seconds.list
+++ b/tz/leap-seconds.list
@@ -204,10 +204,10 @@
 #	current -- the update time stamp, the data and the name of the file
 #	will not change.
 #
-#	Updated through IERS Bulletin C59
-#	File expires on:  28 December 2020
+#	Updated through IERS Bulletin C60
+#	File expires on:  28 June 2021
 #
-#@	3818102400
+#@	3833827200
 #
 2272060800	10	# 1 Jan 1972
 2287785600	11	# 1 Jul 1972
@@ -252,4 +252,4 @@
 #	the hash line is also ignored in the
 #	computation.
 #
-#h	a1c168ae 27c79a7d 9dddcfc3 bcfe616b 2e2c44ea
+#h 	064356a8 39268b92 76e4d5ef 3e22fae1 0cca529c
diff --git a/tz/leapseconds.awk b/tz/leapseconds.awk
index 924ade9..1d3c606 100755
--- a/tz/leapseconds.awk
+++ b/tz/leapseconds.awk
@@ -105,8 +105,10 @@ END {
     print ""
     print "# UTC timestamp when this leap second list expires."
     print "# Any additional leap seconds will come after this."
-    print "# This Expires line is commented out for now,"
-    print "# so that pre-2020a zic implementations do not reject this file."
+    if (! EXPIRES_LINE) {
+      print "# This Expires line is commented out for now,"
+      print "# so that pre-2020a zic implementations do not reject this file."
+    }
     printf "%sExpires %.4d\t%s\t%.2d\t%.2d:%.2d:%.2d\n", \
       EXPIRES_LINE ? "" : "#", \
       ss_year, monthabbr[ss_month], ss_mday, ss_hour, ss_min, ss_sec
diff --git a/tz/localtime.c b/tz/localtime.c
index 6623eac..d3e406b 100644
--- a/tz/localtime.c
+++ b/tz/localtime.c
@@ -1355,8 +1355,9 @@ zoneinit(struct state *sp, char const *name)
 }
 
 static void
-tzsetlcl(char const *name)
+tzset_unlocked(void)
 {
+  char const *name = getenv("TZ");
   struct state *sp = lclptr;
   int lcl = name ? strlen(name) < sizeof lcl_TZname : -1;
   if (lcl < 0
@@ -1377,23 +1378,6 @@ tzsetlcl(char const *name)
   lcl_is_set = lcl;
 }
 
-#ifdef STD_INSPIRED
-void
-tzsetwall(void)
-{
-  if (lock() != 0)
-    return;
-  tzsetlcl(NULL);
-  unlock();
-}
-#endif
-
-static void
-tzset_unlocked(void)
-{
-  tzsetlcl(getenv("TZ"));
-}
-
 void
 tzset(void)
 {
diff --git a/tz/newctime.3 b/tz/newctime.3
index 565e89a..cc56e2c 100644
--- a/tz/newctime.3
+++ b/tz/newctime.3
@@ -51,7 +51,9 @@ asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time
 .de q
 \\$3\*(lq\\$1\*(rq\\$2
 ..
-.I Ctime
+The
+.B ctime
+function
 converts a long integer, pointed to by
 .IR clock ,
 and returns a pointer to a
@@ -86,45 +88,55 @@ and can therefore represent timestamps that predate the
 introduction of UTC and are some other flavor of Universal Time (UT).
 Some implementations support leap seconds, in contradiction to POSIX.
 .PP
-.I Localtime
+The
+.B localtime
 and
-.I gmtime
+.B gmtime
+functions
 return pointers to
 .q "tm"
 structures, described below.
-.I Localtime
+The
+.B localtime
+function
 corrects for the time zone and any time zone adjustments
 (such as Daylight Saving Time in the United States).
 After filling in the
 .q "tm"
 structure,
-.I localtime
+.B localtime
 sets the
 .BR tm_isdst 'th
 element of
 .B tzname
 to a pointer to a string that's the time zone abbreviation to be used with
-.IR localtime 's
+.BR localtime 's
 return value.
 .PP
-.I Gmtime
+The
+.B gmtime
+function
 converts to Coordinated Universal Time.
 .PP
-.I Asctime
+The
+.B asctime
+function
 converts a time value contained in a
 .q "tm"
 structure to a string,
 as shown in the above example,
 and returns a pointer to the string.
 .PP
-.I Mktime
+The
+.B mktime
+function
 converts the broken-down time,
 expressed as local time,
 in the structure pointed to by
 .I tm
 into a calendar time value with the same encoding as that of the values
 returned by the
-.I time
+.B time
 function.
 The original values of the
 .B tm_wday
@@ -136,14 +148,14 @@ to their normal ranges.
 (A positive or zero value for
 .B tm_isdst
 causes
-.I mktime
+.B mktime
 to presume initially that daylight saving time
 respectively,
 is or is not in effect for the specified time.
 A negative value for
 .B tm_isdst
 causes the
-.I mktime
+.B mktime
 function to attempt to divine whether daylight saving time is in effect
 for the specified time; in this case it does not use a consistent
 rule and may give a different answer when later
@@ -161,29 +173,37 @@ is not set until
 and
 .B tm_year
 are determined.
-.I Mktime
+The
+.B mktime
+function
 returns the specified calendar time;
 If the calendar time cannot be represented,
 it returns \-1.
 .PP
-.I Difftime
+The
+.B difftime
+function
 returns the difference between two calendar times,
 .RI ( time1
 \-
 .IR time0 ),
 expressed in seconds.
 .PP
-.IR Ctime_r ,
-.IR localtime_r ,
-.IR gmtime_r ,
+The
+.BR ctime_r ,
+.BR localtime_r ,
+.BR gmtime_r ,
 and
-.I asctime_r
+.B asctime_r
+functions
 are like their unsuffixed counterparts, except that they accept an
 additional argument specifying where to store the result if successful.
 .PP
-.IR Localtime_rz
+The
+.B localtime_rz
 and
-.I mktime_z
+.B mktime_z
+functions
 are like their unsuffixed counterparts, except that they accept an
 extra initial
 .B zone
@@ -193,9 +213,9 @@ If
 is null, UT is used; otherwise,
 .B zone
 should be have been allocated by
-.I tzalloc
+.B tzalloc
 and should not be freed until after all uses (e.g., by calls to
-.IR strftime )
+.BR strftime )
 of the filled-in
 .B tm_zone
 fields.
@@ -227,21 +247,25 @@ includes the following fields:
 .fi
 .RE
 .PP
-.I Tm_isdst
+The
+.B tm_isdst
+field
 is non-zero if daylight saving time is in effect.
 .PP
-.I Tm_gmtoff
+The
+.B tm_gmtoff
+field
 is the offset (in seconds) of the time represented
 from UT, with positive values indicating east
 of the Prime Meridian.
 The field's name is derived from Greenwich Mean Time, a precursor of UT.
 .PP
 In
-.B struct tm
+.B "struct tm"
 the
-.I tm_zone
+.B tm_zone
 and
-.I tm_gmtoff
+.B tm_gmtoff
 fields exist, and are filled in, only if arrangements to do
 so were made when the library containing these functions was
 created.
@@ -273,11 +297,11 @@ time(2),
 tzfile(5)
 .SH NOTES
 The return values of
-.IR asctime ,
-.IR ctime ,
-.IR gmtime ,
+.BR asctime ,
+.BR ctime ,
+.BR gmtime ,
 and
-.I localtime
+.B localtime
 point to static data
 overwritten by each call.
 The
@@ -288,19 +312,21 @@ field of a returned
 .B "struct tm"
 both point to an array of characters that
 can be freed or overwritten by later calls to the functions
-.IR localtime ,
-.IR tzfree ,
+.BR localtime ,
+.BR tzfree ,
 and
-.IR tzset ,
+.BR tzset ,
 if these functions affect the timezone information that specifies the
 abbreviation in question.
 The remaining functions and data are thread-safe.
 .PP
-.IR Asctime ,
-.IR asctime_r ,
-.IR ctime ,
+The
+.BR asctime ,
+.BR asctime_r ,
+.BR ctime ,
 and
-.I ctime_r
+.B ctime_r
+functions
 behave strangely for years before 1000 or after 9999.
 The 1989 and 1999 editions of the C Standard say
 that years from \-99 through 999 are converted without
@@ -311,7 +337,7 @@ is undefined if the year is before 1000 or after 9999.
 Traditional implementations of these two functions are
 restricted to years in the range 1900 through 2099.
 To avoid this portability mess, new programs should use
-.I strftime
+.B strftime
 instead.
 .\" This file is in the public domain, so clarified as of
 .\" 2009-05-17 by Arthur David Olson.
diff --git a/tz/newstrftime.3 b/tz/newstrftime.3
index eee503e..887aba5 100644
--- a/tz/newstrftime.3
+++ b/tz/newstrftime.3
@@ -50,20 +50,22 @@ strftime \- format date and time
 .B cc ... \-ltz
 .fi
 .SH DESCRIPTION
-.ie '\(en'' .ds en \-
-.el .ds en \(en
 .ie '\(lq'' .ds lq \&"\"
 .el .ds lq \(lq\"
 .ie '\(rq'' .ds rq \&"\"
 .el .ds rq \(rq\"
+.de c
+.ie \n(.g \f(CW\\$1\fP\\$2
+.el \\$1\\$2
+..
 .de q
 \\$3\*(lq\\$1\*(rq\\$2
 ..
 The
-.I strftime
+.B strftime
 function formats the information from
 .I timeptr
-into the buffer
+into the array pointed to by
 .I buf
 according to the string pointed to by
 .IR format .
@@ -72,24 +74,17 @@ The
 .I format
 string consists of zero or more conversion specifications and
 ordinary characters.
-All ordinary characters are copied directly into the buffer.
+All ordinary characters are copied directly into the array.
 A conversion specification consists of a percent sign
 .Ql %
 and one other character.
 .PP
 No more than
 .I maxsize
-characters are placed into the array.
-If the total number of resulting characters, including the terminating
-null character, is not more than
-.IR maxsize ,
-.I strftime
-returns the number of characters in the array, not counting the
-terminating null.
-Otherwise, zero is returned.
+bytes are placed into the array.
 .PP
 Each conversion specification is replaced by the characters as
-follows which are then copied into the buffer.
+follows which are then copied into the array.
 .TP
 %A
 is replaced by the locale's full weekday name.
@@ -105,99 +100,122 @@ is replaced by the locale's abbreviated month name.
 .TP
 %C
 is replaced by the century (a year divided by 100 and truncated to an integer)
-as a decimal number (00\*(en99).
+as a decimal number [00,99].
 .TP
 %c
 is replaced by the locale's appropriate date and time representation.
 .TP
 %D
-is replaced by the date in the format %m/%d/%y.
+is equivalent to
+.c %m/%d/%y .
 .TP
 %d
-is replaced by the day of the month as a decimal number (01\*(en31).
+is replaced by the day of the month as a decimal number [01,31].
 .TP
 %e
-is replaced by the day of month as a decimal number (1\*(en31);
+is replaced by the day of month as a decimal number [1,31];
 single digits are preceded by a blank.
 .TP
 %F
-is replaced by the date in the format %Y\*-%m\*-%d.
+is equivalent to
+.c %Y-%m-%d
+(the ISO 8601 date format).
 .TP
 %G
 is replaced by the ISO 8601 year with century as a decimal number.
+See also the
+.c %V
+conversion specification.
 .TP
 %g
-is replaced by the ISO 8601 year without century as a decimal number (00\*(en99).
+is replaced by the ISO 8601 year without century as a decimal number [00,99].
+This is the year that includes the greater part of the week.
+(Monday as the first day of a week).
+See also the
+.c %V
+conversion specification.
 .TP
 %H
-is replaced by the hour (24-hour clock) as a decimal number (00\*(en23).
+is replaced by the hour (24-hour clock) as a decimal number [00,23].
 .TP
 %I
-is replaced by the hour (12-hour clock) as a decimal number (01\*(en12).
+is replaced by the hour (12-hour clock) as a decimal number [01,12].
 .TP
 %j
-is replaced by the day of the year as a decimal number (001\*(en366).
+is replaced by the day of the year as a decimal number [001,366].
 .TP
 %k
-is replaced by the hour (24-hour clock) as a decimal number (0\*(en23);
+is replaced by the hour (24-hour clock) as a decimal number [0,23];
 single digits are preceded by a blank.
 .TP
 %l
-is replaced by the hour (12-hour clock) as a decimal number (1\*(en12);
+is replaced by the hour (12-hour clock) as a decimal number [1,12];
 single digits are preceded by a blank.
 .TP
 %M
-is replaced by the minute as a decimal number (00\*(en59).
+is replaced by the minute as a decimal number [00,59].
 .TP
 %m
-is replaced by the month as a decimal number (01\*(en12).
+is replaced by the month as a decimal number [01,12].
 .TP
 %n
 is replaced by a newline.
 .TP
 %p
-is replaced by the locale's equivalent of either AM or PM.
+is replaced by the locale's equivalent of either
+.q AM
+or
+.q PM .
 .TP
 %R
-is replaced by the time in the format %H:%M.
+is replaced by the time in the format
+.c %H:%M .
 .TP
 %r
 is replaced by the locale's representation of 12-hour clock time
 using AM/PM notation.
 .TP
 %S
-is replaced by the second as a decimal number (00\*(en60).
+is replaced by the second as a decimal number [00,60].
+The range of
+seconds is [00,60] instead of [00,59] to allow for the periodic occurrence
+of leap seconds.
 .TP
 %s
-is replaced by the number of seconds since the Epoch (see newctime(3)).
+is replaced by the number of seconds since the Epoch (see
+.BR ctime (3)).
 .TP
 %T
-is replaced by the time in the format %H:%M:%S.
+is replaced by the time in the format
+.c %H:%M:%S .
 .TP
 %t
 is replaced by a tab.
 .TP
 %U
 is replaced by the week number of the year (Sunday as the first day of
-the week) as a decimal number (00\*(en53).
+the week) as a decimal number [00,53].
 .TP
 %u
 is replaced by the weekday (Monday as the first day of the week)
-as a decimal number (1\*(en7).
+as a decimal number [1,7].
 .TP
 %V
 is replaced by the week number of the year (Monday as the first day of
-the week) as a decimal number (01\*(en53).  If the week containing January
+the week) as a decimal number [01,53].  If the week containing January
 1 has four or more days in the new year, then it is week 1; otherwise
 it is week 53 of the previous year, and the next week is week 1.
+The year is given by the
+.c %G
+conversion specification.
 .TP
 %W
 is replaced by the week number of the year (Monday as the first day of
-the week) as a decimal number (00\*(en53).
+the week) as a decimal number [00,53].
 .TP
 %w
 is replaced by the weekday (Sunday as the first day of the week)
-as a decimal number (0\*(en6).
+as a decimal number [0,6].
 .TP
 %X
 is replaced by the locale's appropriate time representation.
@@ -209,7 +227,7 @@ is replaced by the locale's appropriate date representation.
 is replaced by the year with century as a decimal number.
 .TP
 %y
-is replaced by the year without century as a decimal number (00\*(en99).
+is replaced by the year without century as a decimal number [00,99].
 .TP
 %Z
 is replaced by the time zone abbreviation,
@@ -217,7 +235,7 @@ or by the empty string if this is not determinable.
 .TP
 %z
 is replaced by the offset from the Prime Meridian
-in the format +HHMM or \*-HHMM as appropriate,
+in the format +HHMM or \*-HHMM (ISO 8601) as appropriate,
 with positive values representing locations east of Greenwich,
 or by the empty string if this is not determinable.
 The numeric time zone abbreviation \*-0000 is used when the time is
@@ -231,7 +249,36 @@ time zone abbreviation begins with
 is replaced by a single %.
 .TP
 %+
-is replaced by the date and time in date(1) format.
+is replaced by the locale's date and time in
+.BR date (1)
+format.
+.SH "RETURN VALUE"
+If the conversion is successful,
+.B strftime
+returns the number of bytes placed into the array, not counting the
+terminating NUL;
+.B errno
+is unchanged if the returned value is zero.
+Otherwise,
+.B errno
+is set to indicate the error, zero is returned,
+and the array contents are unspecified.
+.SH ERRORS
+This function fails if:
+.TP
+[ERANGE]
+The total number of resulting bytes, including the terminating
+NUL character, is more than
+.IR maxsize .
+.PP
+This function may fail if:
+.TP
+[EOVERFLOW]
+The format includes an
+.c %s
+conversion and the number of seconds since the Epoch cannot be represented
+in a
+.c time_t .
 .SH SEE ALSO
 date(1),
 getenv(3),
@@ -239,3 +286,5 @@ newctime(3),
 newtzset(3),
 time(2),
 tzfile(5)
+.SH BUGS
+There is no conversion specification for the phase of the moon.
diff --git a/tz/newtzset.3 b/tz/newtzset.3
index 4959851..05aa350 100644
--- a/tz/newtzset.3
+++ b/tz/newtzset.3
@@ -25,49 +25,55 @@ tzset \- initialize time conversion information
 .de q
 \\$3\*(lq\\$1\*(rq\\$2
 ..
-.I Tzalloc
+The
+.B tzalloc
+function
 allocates and returns a timezone object described by
 .BR TZ .
 If
 .B TZ
 is not a valid timezone description, or if the object cannot be allocated,
-.I tzalloc
+.B tzalloc
 returns a null pointer and sets
 .BR errno .
 .PP
-.I Tzfree
+The
+.B tzfree
+function
 frees a timezone object
 .BR tz ,
 which should have been successfully allocated by
-.IR tzalloc .
+.BR tzalloc .
 This invalidates any
 .B tm_zone
 pointers that
 .B tz
 was used to set.
 .PP
-.I Tzset
+The
+.B tzset
+function
 acts like
 .BR tzalloc(getenv("TZ")) ,
 except it saves any resulting timezone object into internal
 storage that is accessed by
-.IR localtime ,
-.IR localtime_r ,
+.BR localtime ,
+.BR localtime_r ,
 and
-.IR mktime .
+.BR mktime .
 The anonymous shared timezone object is freed by the next call to
-.IR tzset .
+.BR tzset .
 If the implied call to
 .B tzalloc
 fails,
-.I tzset
+.B tzset
 falls back on Universal Time (UT).
 .PP
 If
 .B TZ
 is null, the best available approximation to local (wall
 clock) time, as specified by the
-.IR tzfile (5)-format
+.BR tzfile (5)-format
 file
 .B localtime
 in the system time conversion information directory, is used.
@@ -76,7 +82,7 @@ If
 is the empty string,
 UT is used, with the abbreviation "UTC"
 and without leap second correction; please see
-.IR newctime (3)
+.BR newctime (3)
 for more about UT, UTC, and leap seconds.  If
 .B TZ
 is nonnull and nonempty:
@@ -96,7 +102,7 @@ it is used as an absolute pathname; otherwise,
 it is used as a pathname relative to a system time conversion information
 directory.
 The file must be in the format specified in
-.IR tzfile (5).
+.BR tzfile (5).
 .PP
 When
 .B TZ
@@ -304,7 +310,7 @@ is present in
 .BR TZ ,
 the rules specified
 by the
-.IR tzfile (5)-format
+.BR tzfile (5)-format
 file
 .B posixrules
 in the system time conversion information directory are used, with the
diff --git a/tz/northamerica b/tz/northamerica
index febf05b..675c648 100644
--- a/tz/northamerica
+++ b/tz/northamerica
@@ -170,7 +170,7 @@
 # U.S. government action.  So even though the "US" rules have changed
 # in the latest release, other countries won't be affected.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	US	1918	1919	-	Mar	lastSun	2:00	1:00	D
 Rule	US	1918	1919	-	Oct	lastSun	2:00	0	S
 Rule	US	1942	only	-	Feb	9	2:00	1:00	W # War
@@ -347,7 +347,7 @@ Zone	PST8PDT		 -8:00	US	P%sT
 # Eastern time (i.e., -4:56:01.6) just before the 1883 switch.  Round to the
 # nearest second.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	NYC	1920	only	-	Mar	lastSun	2:00	1:00	D
 Rule	NYC	1920	only	-	Oct	lastSun	2:00	0	S
 Rule	NYC	1921	1966	-	Apr	lastSun	2:00	1:00	D
@@ -431,7 +431,7 @@ Zone America/New_York	-4:56:02 -	LMT	1883 Nov 18 12:03:58
 # The Tennessean 2007-05-11, republished 2015-04-06.
 # https://www.tennessean.com/story/insider/extras/2015/04/06/archives-seigenthaler-for-100-years-the-tennessean-had-it-covered/25348545/
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	Chicago	1920	only	-	Jun	13	2:00	1:00	D
 Rule	Chicago	1920	1921	-	Oct	lastSun	2:00	0	S
 Rule	Chicago	1921	only	-	Mar	lastSun	2:00	1:00	D
@@ -500,7 +500,7 @@ Zone America/North_Dakota/Beulah -6:47:07 - LMT	1883 Nov 18 12:12:53
 # El Paso Times. 2018-10-24 06:40 -06.
 # https://www.elpasotimes.com/story/news/local/el-paso/2018/10/24/el-pasoans-were-time-rebels-fought-stay-mountain-zone/1744509002/
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	Denver	1920	1921	-	Mar	lastSun	2:00	1:00	D
 Rule	Denver	1920	only	-	Oct	lastSun	2:00	0	S
 Rule	Denver	1921	only	-	May	22	2:00	0	S
@@ -553,7 +553,7 @@ Zone America/Denver	-6:59:56 -	LMT	1883 Nov 18 12:00:04
 # https://repository.uchastings.edu/cgi/viewcontent.cgi?article=1501&context=ca_ballot_props
 # https://repository.uchastings.edu/cgi/viewcontent.cgi?article=1636&context=ca_ballot_props
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	CA	1948	only	-	Mar	14	2:01	1:00	D
 Rule	CA	1949	only	-	Jan	 1	2:00	0	S
 Rule	CA	1950	1966	-	Apr	lastSun	1:00	1:00	D
@@ -911,7 +911,7 @@ Zone America/Boise	-7:44:49 -	LMT	1883 Nov 18 12:15:11
 # going to switch from Central to Eastern Time on March 11, 2007....
 # http://www.indystar.com/apps/pbcs.dll/article?AID=/20070207/LOCAL190108/702070524/0/LOCAL
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 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
@@ -930,7 +930,7 @@ Zone America/Indiana/Indianapolis -5:44:38 - LMT	1883 Nov 18 12:15:22
 #
 # Eastern Crawford County, Indiana, left its clocks alone in 1974,
 # as well as from 1976 through 2005.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	Marengo	1951	only	-	Apr	lastSun	2:00	1:00	D
 Rule	Marengo	1951	only	-	Sep	lastSun	2:00	0	S
 Rule	Marengo	1954	1960	-	Apr	lastSun	2:00	1:00	D
@@ -949,7 +949,7 @@ Zone America/Indiana/Marengo -5:45:23 -	LMT	1883 Nov 18 12:14:37
 # Daviess, Dubois, Knox, and Martin Counties, Indiana,
 # switched from eastern to central time in April 2006, then switched back
 # in November 2007.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule Vincennes	1946	only	-	Apr	lastSun	2:00	1:00	D
 Rule Vincennes	1946	only	-	Sep	lastSun	2:00	0	S
 Rule Vincennes	1953	1954	-	Apr	lastSun	2:00	1:00	D
@@ -974,7 +974,7 @@ Zone America/Indiana/Vincennes -5:50:07 - LMT	1883 Nov 18 12:09:53
 # The Indianapolis News, Friday 27 October 1967 states that Perry County
 # returned to CST.  It went again to EST on 27 April 1969, as documented by the
 # Indianapolis star of Saturday 26 April.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule Perry	1955	only	-	May	 1	0:00	1:00	D
 Rule Perry	1955	1960	-	Sep	lastSun	2:00	0	S
 Rule Perry	1956	1963	-	Apr	lastSun	2:00	1:00	D
@@ -991,7 +991,7 @@ Zone America/Indiana/Tell_City -5:47:03 - LMT	1883 Nov 18 12:12:57
 #
 # Pike County, Indiana moved from central to eastern time in 1977,
 # then switched back in 2006, then switched back again in 2007.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	Pike	1955	only	-	May	 1	0:00	1:00	D
 Rule	Pike	1955	1960	-	Sep	lastSun	2:00	0	S
 Rule	Pike	1956	1964	-	Apr	lastSun	2:00	1:00	D
@@ -1012,7 +1012,7 @@ Zone America/Indiana/Petersburg -5:49:07 - LMT	1883 Nov 18 12:10:53
 # An article on page A3 of the Sunday, 1991-10-27 Washington Post
 # notes that Starke County switched from Central time to Eastern time as of
 # 1991-10-27.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	Starke	1947	1961	-	Apr	lastSun	2:00	1:00	D
 Rule	Starke	1947	1954	-	Sep	lastSun	2:00	0	S
 Rule	Starke	1955	1956	-	Oct	lastSun	2:00	0	S
@@ -1029,7 +1029,7 @@ Zone America/Indiana/Knox -5:46:30 -	LMT	1883 Nov 18 12:13:30
 #
 # Pulaski County, Indiana, switched from eastern to central time in
 # April 2006 and then switched back in March 2007.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule	Pulaski	1946	1960	-	Apr	lastSun	2:00	1:00	D
 Rule	Pulaski	1946	1954	-	Sep	lastSun	2:00	0	S
 Rule	Pulaski	1955	1956	-	Oct	lastSun	2:00	0	S
@@ -1071,7 +1071,7 @@ Zone America/Indiana/Vevay -5:40:16 -	LMT	1883 Nov 18 12:19:44
 #
 # Part of Kentucky left its clocks alone in 1974.
 # This also includes Clark, Floyd, and Harrison counties in Indiana.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule Louisville	1921	only	-	May	1	2:00	1:00	D
 Rule Louisville	1921	only	-	Sep	1	2:00	0	S
 Rule Louisville	1941	only	-	Apr	lastSun	2:00	1:00	D
@@ -1185,7 +1185,7 @@ Zone America/Kentucky/Monticello -5:39:24 - LMT	1883 Nov 18 12:20:36
 # election Michigan voters narrowly repealed DST, effective 1969.
 #
 # Most of Michigan observed DST from 1973 on, but was a bit late in 1975.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -1202,7 +1202,7 @@ Zone America/Detroit	-5:32:11 -	LMT	1905
 #
 # Dickinson, Gogebic, Iron, and Menominee Counties, Michigan,
 # switched from EST to CST/CDT in 1973.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER
 Rule Menominee	1946	only	-	Apr	lastSun	2:00	1:00	D
 Rule Menominee	1946	only	-	Sep	lastSun	2:00	0	S
 Rule Menominee	1966	only	-	Apr	lastSun	2:00	1:00	D
@@ -1372,7 +1372,7 @@ Zone America/Menominee	-5:50:27 -	LMT	1885 Sep 18 12:00
 # Oct 31, to Oct 27, 1918 (and Sunday is a more likely transition day
 # than Thursday) in all Canadian rulesets.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Canada	1918	only	-	Apr	14	2:00	1:00	D
 Rule	Canada	1918	only	-	Oct	27	2:00	0	S
 Rule	Canada	1942	only	-	Feb	 9	2:00	1:00	W # War
@@ -1395,7 +1395,7 @@ Rule	Canada	2007	max	-	Nov	Sun>=1	2:00	0	S
 # that follows the rules is the southeast corner, including Port Hope
 # Simpson and Mary's Harbour, but excluding, say, Black Tickle.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	StJohns	1917	only	-	Apr	 8	2:00	1:00	D
 Rule	StJohns	1917	only	-	Sep	17	2:00	0	S
 # Whitman gives 1919 Apr 5 and 1920 Apr 5; go with Shanks & Pottenger.
@@ -1497,7 +1497,7 @@ Zone America/Goose_Bay	-4:01:40 -	LMT	1884 # Happy Valley-Goose Bay
 # bill say that it is "accommodating the customs and practices" of those
 # regions, which suggests that they have always been in-line with Halifax.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Halifax	1916	only	-	Apr	 1	0:00	1:00	D
 Rule	Halifax	1916	only	-	Oct	 1	0:00	0	S
 Rule	Halifax	1920	only	-	May	 9	0:00	1:00	D
@@ -1563,7 +1563,7 @@ Zone America/Glace_Bay	-3:59:48 -	LMT	1902 Jun 15
 # clear that this was the case since at least 1993.
 # For now, assume it started in 1993.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Moncton	1933	1935	-	Jun	Sun>=8	1:00	1:00	D
 Rule	Moncton	1933	1935	-	Sep	Sun>=8	1:00	0	S
 Rule	Moncton	1936	1938	-	Jun	Sun>=1	1:00	1:00	D
@@ -1772,7 +1772,7 @@ Zone America/Blanc-Sablon -3:48:28 -	LMT	1884
 #   With some exceptions, the use of daylight saving may be said to be limited
 # to those cities and towns lying between Quebec city and Windsor, Ont.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Toronto	1919	only	-	Mar	30	23:30	1:00	D
 Rule	Toronto	1919	only	-	Oct	26	0:00	0	S
 Rule	Toronto	1920	only	-	May	 2	2:00	1:00	D
@@ -1870,7 +1870,7 @@ Zone America/Atikokan	-6:06:28 -	LMT	1895
 # starting 1966.  Since 02:00s is clearly correct for 1967 on, assume
 # it was also 02:00s in 1966.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Winn	1916	only	-	Apr	23	0:00	1:00	D
 Rule	Winn	1916	only	-	Sep	17	0:00	0	S
 Rule	Winn	1918	only	-	Apr	14	2:00	1:00	D
@@ -1961,7 +1961,7 @@ Zone America/Winnipeg	-6:28:36 -	LMT	1887 Jul 16
 # long and rather painful to read.
 # http://www.qp.gov.sk.ca/documents/English/Statutes/Statutes/T14.pdf
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Regina	1918	only	-	Apr	14	2:00	1:00	D
 Rule	Regina	1918	only	-	Oct	27	2:00	0	S
 Rule	Regina	1930	1934	-	May	Sun>=1	0:00	1:00	D
@@ -2011,7 +2011,7 @@ Zone America/Swift_Current -7:11:20 -	LMT	1905 Sep
 # Boyer JP. Forcing Choice: The Risky Reward of Referendums. Dundum. 2017.
 # ISBN 978-1459739123.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Edm	1918	1919	-	Apr	Sun>=8	2:00	1:00	D
 Rule	Edm	1918	only	-	Oct	27	2:00	0	S
 Rule	Edm	1919	only	-	May	27	2:00	0	S
@@ -2120,7 +2120,7 @@ Zone America/Edmonton	-7:33:52 -	LMT	1906 Sep
 # https://searcharchives.vancouver.ca/daylight-saving-1918-starts-again-july-7-1941-start-d-s-sept-27-end-of-d-s-1941
 # We have no further details, so omit them for now.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Vanc	1918	only	-	Apr	14	2:00	1:00	D
 Rule	Vanc	1918	only	-	Oct	27	2:00	0	S
 Rule	Vanc	1942	only	-	Feb	 9	2:00	1:00	W # War
@@ -2449,7 +2449,19 @@ Zone America/Creston	-7:46:04 -	LMT	1884
 # consistency with nearby Dawson Creek, Creston, and Fort Nelson.
 # https://yukon.ca/en/news/yukon-end-seasonal-time-change
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# From Andrew G. Smith (2020-09-24):
+# Yukon has completed its regulatory change to be on UTC -7 year-round....
+# http://www.gov.yk.ca/legislation/regs/oic2020_125.pdf
+# What we have done is re-defined Yukon Standard Time, as we are
+# authorized to do under section 33 of our Interpretation Act:
+# http://www.gov.yk.ca/legislation/acts/interpretation_c.pdf
+#
+# From Paul Eggert (2020-09-24):
+# tzdb uses the obsolete YST abbreviation for standard time in Yukon through
+# about 1970, and uses PST for standard time in Yukon since then.  Consistent
+# with that, use MST for -07, the new standard time in Yukon effective Nov. 1.
+
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	NT_YK	1918	only	-	Apr	14	2:00	1:00	D
 Rule	NT_YK	1918	only	-	Oct	27	2:00	0	S
 Rule	NT_YK	1919	only	-	May	25	2:00	1:00	D
@@ -2503,12 +2515,12 @@ Zone America/Inuvik	0	-	-00	1953 # Inuvik founded
 Zone America/Whitehorse	-9:00:12 -	LMT	1900 Aug 20
 			-9:00	NT_YK	Y%sT	1967 May 28  0:00
 			-8:00	NT_YK	P%sT	1980
-			-8:00	Canada	P%sT	2020 Mar  8  2:00
+			-8:00	Canada	P%sT	2020 Nov  1
 			-7:00	-	MST
 Zone America/Dawson	-9:17:40 -	LMT	1900 Aug 20
 			-9:00	NT_YK	Y%sT	1973 Oct 28  0:00
 			-8:00	NT_YK	P%sT	1980
-			-8:00	Canada	P%sT	2020 Mar  8  2:00
+			-8:00	Canada	P%sT	2020 Nov  1
 			-7:00	-	MST
 
 
@@ -2723,7 +2735,7 @@ Zone America/Dawson	-9:17:40 -	LMT	1900 Aug 20
 # 5- The islands, reefs and keys shall take their timezone from the
 #    longitude they are located at.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Mexico	1939	only	-	Feb	5	0:00	1:00	D
 Rule	Mexico	1939	only	-	Jun	25	0:00	0	S
 Rule	Mexico	1940	only	-	Dec	9	0:00	1:00	D
@@ -2928,7 +2940,7 @@ Zone America/Tijuana	-7:48:04 -	LMT	1922 Jan  1  0:11:56
 # rules to sync with the U.S. starting in 2007....
 # http://www.jonesbahamas.com/?c=45&a=10412
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -2940,7 +2952,7 @@ Zone	America/Nassau	-5:09:30 -	LMT	1912 Mar 2
 
 # For 1899 Milne gives -3:58:29.2; round that.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Barb	1977	only	-	Jun	12	2:00	1:00	D
 Rule	Barb	1977	1978	-	Oct	Sun>=1	2:00	0	S
 Rule	Barb	1978	1980	-	Apr	Sun>=15	2:00	1:00	D
@@ -2953,7 +2965,7 @@ Zone America/Barbados	-3:58:29 -	LMT	1924 # Bridgetown
 
 # Belize
 # Whitman entirely disagrees with Shanks; go with Shanks & Pottenger.
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Belize	1918	1942	-	Oct	Sun>=2	0:00	0:30	-0530
 Rule	Belize	1919	1943	-	Feb	Sun>=9	0:00	0	CST
 Rule	Belize	1973	only	-	Dec	 5	0:00	1:00	CDT
@@ -2990,7 +3002,7 @@ Zone Atlantic/Bermuda	-4:19:18 -	LMT	1930 Jan  1  2:00 # Hamilton
 
 # Milne gives -5:36:13.3 as San José mean time; round to nearest.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	CR	1979	1980	-	Feb	lastSun	0:00	1:00	D
 Rule	CR	1979	1980	-	Jun	Sun>=1	0:00	0	S
 Rule	CR	1991	1992	-	Jan	Sat>=15	0:00	1:00	D
@@ -3164,7 +3176,7 @@ Zone America/Costa_Rica	-5:36:13 -	LMT	1890        # San José
 # From Paul Eggert (2012-11-03):
 # For now, assume the future rule is first Sunday in November.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Cuba	1928	only	-	Jun	10	0:00	1:00	D
 Rule	Cuba	1928	only	-	Oct	10	0:00	0	S
 Rule	Cuba	1940	1942	-	Jun	Sun>=1	0:00	1:00	D
@@ -3233,7 +3245,7 @@ Zone	America/Havana	-5:29:28 -	LMT	1890
 # decided to revert.
 
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	DR	1966	only	-	Oct	30	0:00	1:00	EDT
 Rule	DR	1967	only	-	Feb	28	0:00	0	EST
 Rule	DR	1969	1973	-	Oct	lastSun	0:00	0:30	-0430
@@ -3250,7 +3262,7 @@ Zone America/Santo_Domingo -4:39:36 -	LMT	1890
 
 # El Salvador
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Salv	1987	1988	-	May	Sun>=1	0:00	1:00	D
 Rule	Salv	1987	1988	-	Sep	lastSun	0:00	0	S
 # There are too many San Salvadors elsewhere, so use America/El_Salvador
@@ -3279,7 +3291,7 @@ Zone America/El_Salvador -5:56:48 -	LMT	1921 # San Salvador
 # (2006-04-19), says DST ends at 24:00.  See
 # http://www.sieca.org.gt/Sitio_publico/Energeticos/Doc/Medidas/Cambio_Horario_Nac_190406.pdf
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Guat	1973	only	-	Nov	25	0:00	1:00	D
 Rule	Guat	1974	only	-	Feb	24	0:00	0	S
 Rule	Guat	1983	only	-	May	21	0:00	1:00	D
@@ -3360,7 +3372,7 @@ Zone America/Guatemala	-6:02:04 -	LMT	1918 Oct 5
 # I have not been able to find a more authoritative source:
 # https://www.haitilibre.com/en/news-20319-haiti-notices-time-change-in-haiti.html
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Haiti	1983	only	-	May	8	0:00	1:00	D
 Rule	Haiti	1984	1987	-	Apr	lastSun	0:00	1:00	D
 Rule	Haiti	1983	1987	-	Oct	lastSun	0:00	0	S
@@ -3408,7 +3420,7 @@ Zone America/Port-au-Prince -4:49:20 -	LMT	1890
 # http://www.laprensahn.com/pais_nota.php?id04962=7386
 # So it seems that Honduras will not enter DST this year....
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Hond	1987	1988	-	May	Sun>=1	0:00	1:00	D
 Rule	Hond	1987	1988	-	Sep	lastSun	0:00	0	S
 Rule	Hond	2006	only	-	May	Sun>=1	0:00	1:00	D
@@ -3499,7 +3511,7 @@ Zone America/Martinique	-4:04:20 -      LMT	1890        # Fort-de-France
 # The natural sun time is restored in all the national territory, in that the
 # time is returned one hour at 01:00 am of October 1 of 2006.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Nic	1979	1980	-	Mar	Sun>=16	0:00	1:00	D
 Rule	Nic	1979	1980	-	Jun	Mon>=23	0:00	0	S
 Rule	Nic	2005	only	-	Apr	10	0:00	1:00	D
diff --git a/tz/pacificnew b/tz/pacificnew
deleted file mode 100644
index 8403219..0000000
--- a/tz/pacificnew
+++ /dev/null
@@ -1,29 +0,0 @@
-# tzdb data for proposed US election time (this file is obsolete)
-
-# This file is in the public domain, so clarified as of
-# 2009-05-17 by Arthur David Olson.
-
-# From Arthur David Olson (1989-04-05):
-# On 1989-04-05, the U. S. House of Representatives passed (238-154) a bill
-# establishing "Pacific Presidential Election Time"; it was not acted on
-# by the Senate or signed into law by the President.
-# You might want to change the "PE" (Presidential Election) below to
-# "Q" (Quadrennial) to maintain three-character zone abbreviations.
-# If you're really conservative, you might want to change it to "D".
-# Avoid "L" (Leap Year), which won't be true in 2100.
-
-# If Presidential Election Time is ever established, replace "XXXX" below
-# with the year the law takes effect and uncomment the "##" lines.
-
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-## Rule	Twilite	XXXX	max	-	Apr	Sun>=1	2:00	1:00	D
-## Rule	Twilite	XXXX	max	uspres	Oct	lastSun	2:00	1:00	PE
-## 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			STDOFF	RULES/SAVE	FORMAT	[UNTIL]
-## Zone	America/Los_Angeles-PET	-8:00	US		P%sT	XXXX
-##				-8:00	Twilite		P%sT
-
-# For now...
-Link	America/Los_Angeles	US/Pacific-New	##
diff --git a/tz/private.h b/tz/private.h
index 8513663..9efcd78 100644
--- a/tz/private.h
+++ b/tz/private.h
@@ -477,8 +477,6 @@ typedef time_tz tz_time_t;
 # define tzfree tz_tzfree
 # undef  tzset
 # define tzset tz_tzset
-# undef  tzsetwall
-# define tzsetwall tz_tzsetwall
 # if HAVE_STRFTIME_L
 #  undef  strftime_l
 #  define strftime_l tz_strftime_l
@@ -551,9 +549,6 @@ extern long altzone;
 */
 
 #ifdef STD_INSPIRED
-# if TZ_TIME_T || !defined tzsetwall
-void tzsetwall(void);
-# endif
 # if TZ_TIME_T || !defined offtime
 struct tm *offtime(time_t const *, long);
 # endif
diff --git a/tz/southamerica b/tz/southamerica
index 9b679c6..aad8b2d 100644
--- a/tz/southamerica
+++ b/tz/southamerica
@@ -48,7 +48,7 @@
 # I am sending modifications to the Argentine time zone table...
 # AR was chosen because they are the ISO letters that represent Argentina.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Arg	1930	only	-	Dec	 1	0:00	1:00	-
 Rule	Arg	1931	only	-	Apr	 1	0:00	0	-
 Rule	Arg	1931	only	-	Oct	15	0:00	1:00	-
@@ -769,7 +769,7 @@ Zone	America/La_Paz	-4:32:36 -	LMT	1890
 # From Paul Eggert (2013-10-17):
 # For now, assume western Amazonas will change as well.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 # Decree 20,466 <http://pcdsh01.on.br/HV20466.htm> (1931-10-01)
 # Decree 21,896 <http://pcdsh01.on.br/HV21896.htm> (1932-01-10)
 Rule	Brazil	1931	only	-	Oct	 3	11:00	1:00	-
@@ -1258,7 +1258,7 @@ Zone America/Rio_Branco	-4:31:12 -	LMT	1914
 # For now, assume that they will not revert,
 # since they have extended the expiration date once already.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Chile	1927	1931	-	Sep	 1	0:00	1:00	-
 Rule	Chile	1928	1932	-	Apr	 1	0:00	0	-
 Rule	Chile	1968	only	-	Nov	 3	4:00u	1:00	-
@@ -1358,7 +1358,7 @@ Zone Antarctica/Palmer	0	-	-00	1965
 # Milne gives 4:56:16.4 for Bogotá time in 1899; round to nearest.  He writes,
 # "A variation of fifteen minutes in the public clocks of Bogota is not rare."
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	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		STDOFF	RULES	FORMAT	[UNTIL]
@@ -1418,7 +1418,7 @@ Link	America/Curacao	America/Kralendijk	# Caribbean Netherlands
 # (Not one step back), the clocks went back in 1993 and the experiment was not
 # repeated.  For now, assume transitions were at 00:00 local time country-wide.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Ecuador	1992	only	-	Nov	28	0:00	1:00	-
 Rule	Ecuador	1993	only	-	Feb	 5	0:00	0	-
 #
@@ -1512,7 +1512,7 @@ Zone Pacific/Galapagos	-5:58:24 -	LMT	1931 # Puerto Baquerizo Moreno
 # For now we will assume permanent -03 for the Falklands
 # until advised differently (to apply for 2012 and beyond, after the 2011
 # experiment was apparently successful.)
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Falk	1937	1938	-	Sep	lastSun	0:00	1:00	-
 Rule	Falk	1938	1942	-	Mar	Sun>=19	0:00	0	-
 Rule	Falk	1939	only	-	Oct	1	0:00	1:00	-
@@ -1558,7 +1558,7 @@ Zone	America/Guyana	-3:52:40 -	LMT	1915 Mar    # Georgetown
 # No time of the day is established for the adjustment, so people normally
 # adjust their clocks at 0 hour of the given dates.
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Para	1975	1988	-	Oct	 1	0:00	1:00	-
 Rule	Para	1975	1978	-	Mar	 1	0:00	0	-
 Rule	Para	1979	1991	-	Apr	 1	0:00	0	-
@@ -1651,7 +1651,7 @@ Zone America/Asuncion	-3:50:40 -	LMT	1890
 # From Paul Eggert (2006-03-22):
 # Shanks & Pottenger don't have this transition.  Assume 1986 was like 1987.
 
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Peru	1938	only	-	Jan	 1	0:00	1:00	-
 Rule	Peru	1938	only	-	Apr	 1	0:00	0	-
 Rule	Peru	1938	1939	-	Sep	lastSun	0:00	1:00	-
@@ -1747,7 +1747,7 @@ Link America/Port_of_Spain America/Tortola	# Virgin Islands (UK)
 # https://www.impo.com.uy/diariooficial/1926/03/10/2
 # https://www.impo.com.uy/diariooficial/1926/03/18/2
 #
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	-	IN	ON	AT	SAVE	LETTER/S
 Rule	Uruguay	1923	1925	-	Oct	 1	 0:00	0:30	-
 Rule	Uruguay	1924	1926	-	Apr	 1	 0:00	0	-
 # From Tim Parenti (2018-02-15):
diff --git a/tz/strftime.c b/tz/strftime.c
index 14cbc9a..4f871cd 100644
--- a/tz/strftime.c
+++ b/tz/strftime.c
@@ -130,10 +130,15 @@ size_t
 strftime(char *s, size_t maxsize, const char *format, const struct tm *t)
 {
 	char *	p;
+	int saved_errno = errno;
 	enum warn warn = IN_NONE;
 
 	tzset();
 	p = _fmt(format, t, s, s + maxsize, &warn);
+	if (!p) {
+	  errno = EOVERFLOW;
+	  return 0;
+	}
 	if (DEPRECATE_TWO_DIGIT_YEARS
 	    && warn != IN_NONE && getenv(YEAR_2000_NAME)) {
 		fprintf(stderr, "\n");
@@ -146,9 +151,12 @@ strftime(char *s, size_t maxsize, const char *format, const struct tm *t)
 		else	fprintf(stderr, "all locales");
 		fprintf(stderr, "\n");
 	}
-	if (p == s + maxsize)
+	if (p == s + maxsize) {
+		errno = ERANGE;
 		return 0;
+	}
 	*p = '\0';
+	errno = saved_errno;
 	return p - s;
 }
 
@@ -312,7 +320,21 @@ label:
 					time_t		mkt;
 
 					tm = *t;
+					tm.tm_yday = -1;
 					mkt = mktime(&tm);
+					if (mkt == (time_t) -1) {
+					  /* Fail unless this -1 represents
+					     a valid time.  */
+					  struct tm tm_1;
+					  if (!localtime_r(&mkt, &tm_1))
+					    return NULL;
+					  if (!(tm.tm_year == tm_1.tm_year
+						&& tm.tm_yday == tm_1.tm_yday
+						&& tm.tm_hour == tm_1.tm_hour
+						&& tm.tm_min == tm_1.tm_min
+						&& tm.tm_sec == tm_1.tm_sec))
+					    return NULL;
+					}
 					if (TYPE_SIGNED(time_t))
 						sprintf(buf, "%"PRIdMAX,
 							(intmax_t) mkt);
diff --git a/tz/systemv b/tz/systemv
deleted file mode 100644
index a8c037c..0000000
--- a/tz/systemv
+++ /dev/null
@@ -1,39 +0,0 @@
-# tzdb data for System V rules (this file is obsolete)
-
-# This file is in the public domain, so clarified as of
-# 2009-05-17 by Arthur David Olson.
-
-# Old rules, should the need arise.
-# No attempt is made to handle Newfoundland, since it cannot be expressed
-# using the System V "TZ" scheme (half-hour offset), or anything outside
-# North America (no support for non-standard DST start/end dates), nor
-# the changes in the DST rules in the US after 1976 (which occurred after
-# the old rules were written).
-#
-# If you need the old rules, uncomment ## lines.
-# Compile this *without* leap second correction for true conformance.
-
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	SystemV	min	1973	-	Apr	lastSun	2:00	1:00	D
-Rule	SystemV	min	1973	-	Oct	lastSun	2:00	0	S
-Rule	SystemV	1974	only	-	Jan	6	2:00	1:00	D
-Rule	SystemV	1974	only	-	Nov	lastSun	2:00	0	S
-Rule	SystemV	1975	only	-	Feb	23	2:00	1:00	D
-Rule	SystemV	1975	only	-	Oct	lastSun	2:00	0	S
-Rule	SystemV	1976	max	-	Apr	lastSun	2:00	1:00	D
-Rule	SystemV	1976	max	-	Oct	lastSun	2:00	0	S
-
-# 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
-## Zone	SystemV/MST7MDT	-7:00	SystemV		M%sT
-## Zone	SystemV/PST8PDT	-8:00	SystemV		P%sT
-## Zone	SystemV/YST9YDT	-9:00	SystemV		Y%sT
-## Zone	SystemV/AST4	-4:00	-		AST
-## Zone	SystemV/EST5	-5:00	-		EST
-## Zone	SystemV/CST6	-6:00	-		CST
-## Zone	SystemV/MST7	-7:00	-		MST
-## Zone	SystemV/PST8	-8:00	-		PST
-## Zone	SystemV/YST9	-9:00	-		YST
-## Zone	SystemV/HST10	-10:00	-		HST
diff --git a/tz/theory.html b/tz/theory.html
index c0e6f02..4613799 100644
--- a/tz/theory.html
+++ b/tz/theory.html
@@ -33,7 +33,7 @@
 The <a
 href="https://www.iana.org/time-zones"><code><abbr>tz</abbr></code>
 database</a> attempts to record the history and predicted future of
-all computer-based clocks that track civil time.
+civil time scales.
 It organizes <a href="tz-link.html">time zone and daylight saving time
 data</a> by partitioning the world into <a
 href="https://en.wikipedia.org/wiki/List_of_tz_database_time_zones"><dfn>timezones</dfn></a>
@@ -115,17 +115,15 @@ Each timezone has a name that uniquely identifies the timezone.
 Inexperienced users are not expected to select these names unaided.
 Distributors should provide documentation and/or a simple selection
 interface that explains each name via a map or via descriptive text like
-"Ruthenia" instead of the timezone name "<code>Europe/Uzhgorod</code>".
+"Czech Republic" instead of the timezone name "<code>Europe/Prague</code>".
 If geolocation information is available, a selection interface can
 locate the user on a timezone map or prioritize names that are
 geographically close. For an example selection interface, see the
 <code>tzselect</code> program in the <code><abbr>tz</abbr></code> code.
-The <a href="http://cldr.unicode.org/">Unicode Common Locale Data
+The <a href="http://cldr.unicode.org">Unicode Common Locale Data
 Repository</a> contains data that may be useful for other selection
-interfaces; it maps timezone names like <code>Europe/Uzhgorod</code>
-to CLDR names like <code>uauzh</code> which are in turn mapped to
-locale-dependent strings like "Uzhhorod", "Ungvár", "Ужгород", and
-"乌日哥罗德".
+interfaces; it maps timezone names like <code>Europe/Prague</code> to
+locale-dependent strings like "Prague", "Praha", "Прага", and "布拉格".
 </p>
 
 <p>
@@ -693,6 +691,14 @@ href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanes
     <code><abbr>tz</abbr></code> database requires.
   </li>
   <li>
+    The <code><abbr>tz</abbr></code> database cannot represent stopped clocks.
+    However, on 1911-03-11 at 00:00, some public-facing French clocks
+    were changed by stopping them for a few minutes to effect a transition.
+    The <code><abbr>tz</abbr></code> database models this via a
+    backward transition; the relevant French legislation does not
+    specify exactly how the transition was to occur.
+  </li>
+  <li>
     Sometimes historical timekeeping was specified more precisely
     than what the <code><abbr>tz</abbr></code> code can handle.
     For example, from 1909 to 1937 <a
@@ -1321,17 +1327,21 @@ They sometimes disagree.
 <section>
   <h2 id="planets">Time and time zones on other planets</h2>
 <p>
-Some people's work schedules
-use <a href="https://en.wikipedia.org/wiki/Timekeeping_on_Mars">Mars time</a>.
+Some people's work schedules have used
+<a href="https://en.wikipedia.org/wiki/Timekeeping_on_Mars">Mars time</a>.
 Jet Propulsion Laboratory (JPL) coordinators kept Mars time on
 and off during the
 <a href="https://en.wikipedia.org/wiki/Mars_Pathfinder">Mars
-Pathfinder</a> mission.
+Pathfinder</a> mission (1997).
 Some of their family members also adapted to Mars time.
 Dozens of special Mars watches were built for JPL workers who kept
-Mars time during the Mars Exploration Rovers mission (2004).
-These timepieces look like normal Seikos and Citizens but use Mars
-seconds rather than terrestrial seconds.
+Mars time during the
+<a href="https://en.wikipedia.org/wiki/Mars_Exploration_Rover">Mars
+Exploration Rovers (MER)</a> mission (2004&ndash;2018).
+These timepieces looked like normal Seikos and Citizens but were adjusted
+to use Mars seconds rather than terrestrial seconds, although
+unfortunately the adjusted watches were unreliable and appear to have
+had only limited use.
 </p>
 
 <p>
@@ -1339,6 +1349,8 @@ A Mars solar day is called a "sol" and has a mean period equal to
 about 24 hours 39 minutes 35.244 seconds in terrestrial time.
 It is divided into a conventional 24-hour clock, so each Mars second
 equals about 1.02749125 terrestrial seconds.
+(One MER worker noted, "If I am working Mars hours, and Mars hours are
+2.5% more than Earth hours, shouldn't I get an extra 2.5% pay raise?")
 </p>
 
 <p>
@@ -1354,12 +1366,12 @@ called Mars Coordinated Time (<abbr>MTC</abbr>).
 <p>
 Each landed mission on Mars has adopted a different reference for
 solar timekeeping, so there is no real standard for Mars time zones.
-For example, the
-<a href="https://en.wikipedia.org/wiki/Mars_Exploration_Rover">Mars
-Exploration Rover</a> project (2004) defined two time zones "Local
+For example, the MER mission defined two time zones "Local
 Solar Time A" and "Local Solar Time B" for its two missions, each zone
 designed so that its time equals local true solar time at
 approximately the middle of the nominal mission.
+The A and B zones differ enough so that an MER worker assigned to
+the A zone might suffer "Mars lag" when switching to work in the B zone.
 Such a "time zone" is not particularly suited for any application
 other than the mission itself.
 </p>
@@ -1408,7 +1420,12 @@ Sources for time on other planets:
     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>"
-    (2018-12-13).
+    (2020-03-08).
+  </li>
+  <li>
+    Zara Mirmalek,
+    <em><a href="https://mitpress.mit.edu/books/making-time-mars">Making
+	Time on Mars</a></em>, MIT Press (March 2020), ISBN 978-0262043854.
   </li>
   <li>
     Jia-Rui Chong,
diff --git a/tz/time2posix.3 b/tz/time2posix.3
index e4b8e81..fbb5766 100644
--- a/tz/time2posix.3
+++ b/tz/time2posix.3
@@ -47,11 +47,11 @@ to be
 (mostly)
 opaque \*(en time_t values should only be obtained-from and
 passed-to functions such as
-.IR time(2) ,
-.IR localtime(3) ,
-.IR mktime(3) ,
+.BR time(2) ,
+.BR localtime(3) ,
+.BR mktime(3) ,
 and
-.IR difftime(3) .
+.BR difftime(3) .
 However,
 POSIX gives an arithmetic
 expression for directly computing a time_t value from a given date/time,
@@ -63,9 +63,9 @@ using such a relationship will typically not handle intervals
 over leap seconds correctly.
 .PP
 The
-.I time2posix
+.B time2posix
 and
-.I posix2time
+.B posix2time
 functions are provided to address this time_t mismatch by converting
 between local time_t values and their POSIX equivalents.
 This is done by accounting for the number of time-base changes that
@@ -75,12 +75,16 @@ These converted values can then be used in lieu of correcting the older
 applications,
 or when communicating with POSIX-compliant systems.
 .PP
-.I Time2posix
+The
+.B time2posix
+function
 is single-valued.
 That is,
 every local time_t
 corresponds to a single POSIX time_t.
-.I Posix2time
+The
+.B posix2time
+function
 is less well-behaved:
 for a positive leap second hit the result is not unique,
 and for a negative leap second hit the corresponding
@@ -116,9 +120,9 @@ If leap-second support is not enabled,
 local time_t's and
 POSIX time_t's are equivalent,
 and both
-.I time2posix
+.B time2posix
 and
-.I posix2time
+.B posix2time
 degenerate to the identity function.
 .SH SEE ALSO
 difftime(3),
diff --git a/tz/tz-art.html b/tz/tz-art.html
index 93a99e4..72b9654 100644
--- a/tz/tz-art.html
+++ b/tz/tz-art.html
@@ -22,6 +22,10 @@ into problems that programmers have with timekeeping.</li>
 Explaining The Mysteries Of Time Zones</a>" (2017; 2:15)
 briefly says why France has more time zones than Russia.
 <li>
+"<a href="https://www.youtube.com/watch?v=yRz-Dl60Lfc">Why Denmark is
+.17 Seconds Behind The World</a>" (2019; 6:29) explains why Denmark and
+the United Kingdom don't exactly follow their own law about civil time.
+<li>
 "About Time" (1962; 59 minutes) is part of the
 Bell Science extravaganza, with Frank Baxter, Richard Deacon, and Les Tremayne.
 Its advisor was Richard Feynman, and it was voiced by Mel Blanc.
@@ -109,6 +113,11 @@ premonition in the "We Had a Dream" episode of <em>Medium</em>
 (originally aired 2007-02-28).
 </li>
 <li>
+A criminal's failure to account for the start of daylight saving is pivotal
+in "<a href="https://monk.fandom.com/wiki/Mr._Monk_and_the_Rapper">Mr. Monk
+and the Rapper</a>" (first aired 2007-07-20).
+</li>
+<li>
 In the <em>30 Rock</em> episode "Anna Howard Shaw Day"
 (first broadcast 2010-02-11),
 Jack Donaghy's date realizes that a Geneva-to-New-York business phone call
diff --git a/tz/tz-how-to.html b/tz/tz-how-to.html
index 2e4842d..bf3e86f 100644
--- a/tz/tz-how-to.html
+++ b/tz/tz-how-to.html
@@ -1,12 +1,16 @@
-<!DOCTYPE html
-	PUBLIC "-//W3C//DTD HTML 4.01//EN"
-	"http://www.w3.org/TR/html4/strict.dtd">
-<html>
+<!DOCTYPE html>
+<html lang="en">
 <head>
 <title>How to Read the tz Database</title>
-<meta http-equiv="Content-type" content='text/html; charset="UTF-8"'>
-<style type="text/css">
+<meta charset="UTF-8">
+<style>
 pre {margin-left: 2em; white-space: pre-wrap;}
+pre.td {margin-left: 0;}
+td {text-align: center;}
+table {border: 1px outset;}
+th, td {border: 1px inset;}
+table.rule {border: none; margin: auto;}
+td.footnote {text-align: left;}
 </style>
 </head>
 <body>
@@ -31,14 +35,16 @@ about the zones.</p>
 for Chicago (from the <code>northamerica</code> file in
 the <code>data</code> subdirectory):</p>
 
-<table border="1">
+<table>
 <tr>
   <th colspan="6">From the Source File</th>
 </tr>
 <tr>
-  <td colspan="6" align="center"><table><tr><td>
-<pre>
-#Rule NAME    FROM TO   TYPE IN  ON      AT   SAVE LETTER
+  <td colspan="6">
+    <table class="rule">
+      <tr><td style="border:none;text-align:left">
+<pre class="td">
+#Rule NAME    FROM TO    -   IN  ON      AT   SAVE LETTER
 Rule  Chicago 1920 only  -   Jun 13      2:00 1:00 D
 Rule  Chicago 1920 1921  -   Oct lastSun 2:00 0    S
 Rule  Chicago 1921 only  -   Mar lastSun 2:00 1:00 D
@@ -58,49 +64,58 @@ Rule  Chicago 1955 1966  -   Oct lastSun 2:00 0    S
   <th>At</th>
   <th>Action</th>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2">1920 only</td>
   <td colspan="2">June 13<small><sup>th</sup></small></td>
   <td rowspan="6">02:00 local</td>
   <td>go to daylight saving time</td>
 </tr>
-<tr align="center">
+<tr>
   <td>1920</td>
   <td>1921</td>
   <td rowspan="5">last Sunday</td>
   <td>in October</td>
   <td>return to standard time</td>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2">1921 only</td>
   <td>in March</td>
   <td rowspan="2">go to daylight saving time</td>
 </tr>
-<tr align="center">
+<tr>
   <td rowspan="2">1922</td>
   <td>1966</td>
   <td>in April</td>
 </tr>
-<tr align="center">
+<tr>
   <td>1954</td>
   <td>in September</td>
   <td rowspan="2">return to standard time</td>
 </tr>
-<tr align="center">
+<tr>
   <td>1955</td>
   <td>1966</td>
   <td>in October</td>
 </tr>
 </table>
 
-<p>We&rsquo;ll basically just ignore the <code>TYPE</code> column.
-In the 2007j release, the most recent as of this writing, the
-<code>TYPE</code> column never contains anything but a hyphen,
-a kind of null value. (From the description in <code>zic.8.txt</code>,
-this appears to be a mechanism for removing years from a set
-in some localizable way. It&rsquo;s used in the file, <code>pacificnew</code>,
-to determine whether a given year will have a US presidential election;
-but everything related to that use is commented out.)
+<p>The <code>FROM</code> and <code>TO</code> columns, respectively, specify the
+first and last calendar years defining a contiguous range over which a specific
+Rule line is to apply.  The keyword <code>only</code> can be used in the
+<code>TO</code> field to repeat the value of the <code>FROM</code> field in the
+event that a rule should only apply to a single year.  Often, the keyword
+<code>max</code> is used to extend a rule&rsquo;s application into the
+indefinite future; it is a platform-agnostic stand-in for the largest
+representable year.
+
+<p>The next column, <code>-</code>, is reserved; for compatibility with earlier
+releases, it always contains a hyphen, which acts as a kind of null value.
+Prior to the 2020b release, it was called the <code>TYPE</code> field, though
+it was never used in the main data.  An obsolescent supplementary file used the
+field as a proof-of-concept to allow <code>zic</code> to apply a given Rule
+line only to certain &ldquo;types&rdquo; of years within the specified range as
+dictated by the output of a separate script, such as: only years which would
+have a US presidential election, or only years which wouldn&rsquo;t.
 
 <p>The <code>SAVE</code> column contains the local (wall clock) offset from
 local standard time.
@@ -141,14 +156,16 @@ time changed in 1955. Got it?</p>
 
 <p>OK, now for the somewhat more interesting &ldquo;US&rdquo; rules:</p>
 
-<table border="1">
+<table>
 <tr>
   <th colspan="6">From the Source File</th>
 </tr>
 <tr>
-  <td colspan="6" align="center"><table><tr><td>
-<pre>
-#Rule NAME FROM TO   TYPE IN  ON        AT   SAVE LETTER/S
+  <td colspan="6">
+    <table class="rule">
+      <tr><td style="border:none;text-align:left">
+<pre class="td">
+#Rule NAME FROM TO    -   IN  ON        AT   SAVE LETTER/S
 Rule  US   1918 1919  -   Mar lastSun  2:00  1:00 D
 Rule  US   1918 1919  -   Oct lastSun  2:00  0    S
 Rule  US   1942 only  -   Feb 9        2:00  1:00 W # War
@@ -175,7 +192,7 @@ Rule  US   2007 max   -   Nov Sun&gt;=1   2:00  0    S
   <th>At</th>
   <th>Action</th>
 </tr>
-<tr align="center">
+<tr>
   <td rowspan="2">1918</td>
   <td rowspan="2">1919</td>
   <td rowspan="2">last Sunday</td>
@@ -183,16 +200,16 @@ Rule  US   2007 max   -   Nov Sun&gt;=1   2:00  0    S
   <td rowspan="3">02:00 local</td>
   <td>go to daylight saving time</td>
 </tr>
-<tr align="center">
+<tr>
   <td>in October</td>
   <td>return to standard time</td>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2">1942 only</td>
   <td colspan="2">February 9<small><sup>th</sup></small></td>
   <td>go to &ldquo;war time&rdquo;</td>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2" rowspan="2">1945 only</td>
   <td colspan="2">August 14<small><sup>th</sup></small></td>
   <td>23:00 <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a></td>
@@ -201,47 +218,47 @@ Rule  US   2007 max   -   Nov Sun&gt;=1   2:00  0    S
     clocks don&rsquo;t change
   </td>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2">September 30<small><sup>th</sup></small></td>
   <td rowspan="9">02:00 local</td>
   <td rowspan="2">return to standard time</td>
 </tr>
-<tr align="center">
+<tr>
   <td rowspan="2">1967</td>
   <td>2006</td>
   <td rowspan="2">last Sunday</td>
   <td>in October</td>
 </tr>
-<tr align="center">
+<tr>
   <td>1973</td>
   <td>in April</td>
   <td rowspan="6">go to daylight saving time</td>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2">1974 only</td>
   <td colspan="2">January 6<small><sup>th</sup></small></td>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2">1975 only</td>
   <td colspan="2">February 23<small><sup>rd</sup></small></td>
 </tr>
-<tr align="center">
+<tr>
   <td>1976</td>
   <td>1986</td>
   <td>last Sunday</td>
   <td rowspan="2">in April</td>
 </tr>
-<tr align="center">
+<tr>
   <td>1987</td>
   <td>2006</td>
   <td>first Sunday</td>
 </tr>
-<tr align="center">
+<tr>
   <td rowspan="2">2007</td>
   <td rowspan="2">present</td>
   <td colspan="2">second Sunday in March</td>
 </tr>
-<tr align="center">
+<tr>
   <td colspan="2">first Sunday in November</td>
   <td>return to standard time</td>
 </tr>
@@ -307,13 +324,15 @@ rule, so there should be no change.</li>
 
 <p>OK, now let&rsquo;s look at a Zone record:</p>
 
-<table border="1">
+<table>
 <tr>
   <th colspan="5">From the Source File</th>
 </tr>
 <tr>
-  <td colspan="6" align="center"><table><tr><td>
-<pre>
+  <td colspan="5">
+    <table class="rule">
+      <tr><td style="border:none;text-align:left">
+<pre class="td">
 #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
@@ -341,49 +360,49 @@ Zone  America/Chicago -5:50:36 -       LMT  1883 Nov 18 12:09:24
   <th>Date</th>
   <th>Time</th>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;5:50:36</td>
   <td>not observed</td>
   <td>LMT</td>
   <td>1883-11-18</td>
   <td>12:09:24</td>
 </tr>
-<tr align="center">
+<tr>
   <td rowspan="2">&minus;6:00:00</td>
   <td>US rules</td>
   <td rowspan="2">CST or CDT</td>
   <td>1920-01-01</td>
   <td>00:00:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td>Chicago rules</td>
   <td>1936-03-01</td>
   <td rowspan="2">02:00:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;5:00:00</td>
   <td>not observed</td>
   <td>EST</td>
   <td>1936-11-15</td>
 </tr>
-<tr align="center">
+<tr>
   <td rowspan="4">&minus;6:00:00</td>
   <td>Chicago rules</td>
   <td>CST or CDT</td>
   <td>1942-01-01</td>
   <td rowspan="3">00:00:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td>US rules</td>
   <td>CST, CWT or CPT</td>
   <td>1946-01-01</td>
 </tr>
-<tr align="center">
+<tr>
   <td>Chicago rules</td>
   <td rowspan="2">CST or CDT</td>
   <td>1967-01-01</td>
 </tr>
-<tr align="center">
+<tr>
   <td>US rules</td>
   <td colspan="2">&mdash;</td>
 </tr>
@@ -548,14 +567,16 @@ the true offset is undefined.
 
 <p>As a final example, here&rsquo;s the complete history for Hawaii:</p>
 
-<table border="1">
+<table>
 <tr>
   <th colspan="6">Relevant Excerpts from the US Rules</th>
 </tr>
 <tr>
-  <td colspan="6" align="center"><table><tr><td>
-<pre>
-#Rule NAME FROM TO   TYPE IN  ON      AT     SAVE LETTER/S
+  <td colspan="6">
+    <table class="rule">
+      <tr><td style="border:none;text-align:left">
+<pre class="td">
+#Rule NAME FROM TO   -    IN  ON      AT     SAVE LETTER/S
 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
@@ -567,8 +588,10 @@ Rule  US   1945 only -    Sep lastSun  2:00  0    S
   <th colspan="6">The Zone Record</th>
 </tr>
 <tr>
-  <td colspan="6" align="center"><table><tr><td>
-<pre>
+  <td colspan="6">
+    <table class="rule">
+      <tr><td style="border:none;text-align:left">
+<pre class="td">
 #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
@@ -593,7 +616,7 @@ Zone Pacific/Honolulu -10:31:26 -     LMT    1896 Jan 13 12:00
   <th>Date</th>
   <th>Time</th>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;10:31:26</td>
   <td>&mdash;</td>
   <td>LMT</td>
@@ -601,7 +624,7 @@ Zone Pacific/Honolulu -10:31:26 -     LMT    1896 Jan 13 12:00
   <td>1896-01-13</td>
   <td>12:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;10:30</td>
   <td>+0:01:26</td>
   <td>HST</td>
@@ -609,7 +632,7 @@ Zone Pacific/Honolulu -10:31:26 -     LMT    1896 Jan 13 12:00
   <td>1933-04-30</td>
   <td>02:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;9:30</td>
   <td>+1:00</td>
   <td>HDT</td>
@@ -617,7 +640,7 @@ Zone Pacific/Honolulu -10:31:26 -     LMT    1896 Jan 13 12:00
   <td>1933-05-21</td>
   <td>12:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;10:30&sup1;</td>
   <td>&minus;1:00&sup1;</td>
   <td>HST&sup1;</td>
@@ -625,7 +648,7 @@ Zone Pacific/Honolulu -10:31:26 -     LMT    1896 Jan 13 12:00
   <td>1942-02-09</td>
   <td>02:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td rowspan="2">&minus;9:30</td>
   <td>+1:00</td>
   <td>HWT</td>
@@ -633,38 +656,38 @@ Zone Pacific/Honolulu -10:31:26 -     LMT    1896 Jan 13 12:00
   <td>1945-08-14</td>
   <td>13:30&sup2;</td>
 </tr>
-<tr align="center">
+<tr>
   <td>0</td>
   <td>HPT</td>
   <td>Hawaii peace time</td>
   <td>1945-09-30</td>
   <td rowspan="2">02:00</td>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;10:30</td>
   <td>&minus;1:00</td>
   <td rowspan="2">HST</td>
   <td rowspan="2">Hawaii standard time</td>
   <td>1947-06-08</td>
 </tr>
-<tr align="center">
+<tr>
   <td>&minus;10:00&sup3;</td>
   <td>+0:30&sup3;</td>
   <td colspan="2">&mdash;</td>
 </tr>
 <tr>
-  <td colspan="6">
+  <td colspan="6" class="footnote">
     &sup1;Switching to US rules&hellip;most recent transition (in 1919) was to standard time
   </td>
 </tr>
 <tr>
-  <td colspan="6">
+  <td colspan="6" class="footnote">
     &sup2;23:00 <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>
     + (&minus;9:30) = 13:30 local
   </td>
 </tr>
 <tr>
-  <td colspan="6">
+  <td colspan="6" class="footnote">
     &sup3;Since <a href="https://en.wikipedia.org/wiki/ISO_8601">1947&ndash;06&ndash;08T12:30Z</a>,
     the civil time in Hawaii has been
     <a href="https://en.wikipedia.org/wiki/Universal_Time">UT</a>/<a href="https://en.wikipedia.org/wiki/Coordinated_Universal_Time">UTC</a>
diff --git a/tz/tz-link.html b/tz/tz-link.html
index 1f893f6..10c40b5 100644
--- a/tz/tz-link.html
+++ b/tz/tz-link.html
@@ -215,13 +215,18 @@ generated <a href="https://github.com/timparenti/tzdata-meta">automatically</a>.
 If your government plans to change its time zone boundaries or
 daylight saving rules, inform <code>tz@iana.org</code> well in
 advance, as this will coordinate updates to many cell phones,
-computers, and other devices around the world. With
-less than a year's notice there is a good chance that some
-computer-based clocks will operate incorrectly after the change, due
+computers, and other devices around the world.
+The change should be officially announced at least a year before it affects
+how clocks operate; otherwise, there is a good chance that some
+clocks will operate incorrectly after the change, due
 to delays in propagating updates to software and data. The shorter
 the notice, the more likely clock problems will arise; see "<a
 href="https://codeofmatt.com/2016/04/23/on-the-timing-of-time-zone-changes/">On
 the Timing of Time Zone Changes</a>" for examples.
+The <code><abbr>tz</abbr></code> data can represent planned changes
+far into the future, and a long-planned change can easily be reverted
+or otherwise altered with a year's notice before the change would have
+affected clocks.
 </p>
 <p>
 Changes to the <code><abbr>tz</abbr></code> code and data are often
@@ -240,13 +245,12 @@ href="https://play.google.com/store/apps/details?id=com.google.android.timezone.
 <a
 href="http://userguide.icu-project.org/datetime/timezone"><abbr
 title="International Components for Unicode">ICU</abbr></a>,
-<a href="https://developer.ibm.com/javasdk/support/dst/jtzu/"><abbr>IBM</abbr></a>
-and <a
-href="https://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">Oracle</a>
-Java, <a href="https://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, <a
+<a href="https://developer.ibm.com/javasdk/support/dst/jtzu/"><abbr>IBM</abbr>
+JDK</a>,
+<a href="https://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, <a
 href="https://dev.mysql.com/doc/refman/en/time-zone-support.html">MySQL</a>,
-and <a
-href="https://nodatime.org/userguide/tzdb">Noda Time</a> (see below).
+<a href="https://nodatime.org/userguide/tzdb">Noda Time</a>, and <a
+href="https://www.oracle.com/java/technologies/javase/tzupdater-readme.html#usage">OpenJDK/Oracle JDK</a>.
 </p>
 <p>Sources for the <code><abbr>tz</abbr></code> database are
 <a href="https://en.wikipedia.org/wiki/UTF-8"><abbr
@@ -307,6 +311,12 @@ time and zones.</li>
 <a href="https://timezoneconverterapp.com">Time Zone Converter</a> and
 <a href="https://www.worldclock.com">The World Clock</a>
 are time zone converters.</li>
+<li><a href="https://timezonedb.com/download">TimeZoneDB Database</a>
+publishes <code><abbr>tzdb</abbr></code>-derived data in
+<a href="https://en.wikipedia.org/wiki/Comma-separated_values"><abbr
+title="comma-separated values">CSV</abbr></a> and
+in <a href="https://en.wikipedia.org/wiki/SQL"><abbr
+title="Structured Query Language">SQL</abbr></a> form.</li>
 <li><a
 href="https://twiki.org/cgi-bin/xtra/tzdatepick.html">Date and Time Gateway</a>
 lets you see the <code><abbr>TZ</abbr></code> values directly.</li>
@@ -339,6 +349,8 @@ href="https://tools.ietf.org/html/rfc7808">TZDIST</a>
 along with <a href="https://tools.ietf.org/html/rfc7809">CalDAV</a>
 (Internet <abbr>RFC</abbr> 7809), a calendar access protocol for
 transferring time zone data by reference.
+<a href="https://devguide.calconnect.org/Time-Zones/TZDS/">TZDIST
+implementations</a> are available.
 The <a href="https://www.ietf.org/mailman/listinfo/tzdist-bis">tzdist-bis
 mailing list</a> discussed the Internet draft <a
 id="TZDIST-Geolocate"
@@ -423,9 +435,13 @@ freely available under the <abbr>MIT</abbr> license.</li>
 <li>Java-based compilers and libraries include:
 <ul>
 <li>The <a
-href="https://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">TZUpdater
+href="https://www.oracle.com/java/technologies/javase/tzupdater-readme.html">TZUpdater
 tool</a> compiles <code><abbr>tz</abbr></code> source into the format used by
-Oracle Java.</li>
+<a href="https://openjdk.java.net/">OpenJDK</a> and
+<a href="https://jdk.java.net/">Oracle JDK</a>.
+Although its source code is proprietary, its executable is available under the
+<a href="https://www.oracle.com/a/tech/docs/tzupdater-lic.html">Java SE
+Timezone Updater License Agreement</a>.</li>
 <li>The <a
 href="https://www.oracle.com/technetwork/articles/java/jf14-date-time-2125367.html">Java
 SE 8 Date and Time</a> <abbr>API</abbr> can be supplemented by <a
@@ -438,11 +454,10 @@ and time <abbr>API</abbr></a> contains a class
 Java 8 <code>java.time</code>, which its users should migrate to once
 they can assume Java 8 or later. It is available under the <a
 href="https://www.apache.org/licenses/LICENSE-2.0">Apache License</a>.</li>
-<li><a href="https://bell-sw.com/pages/iana-updater/">IANA Updater</a>,
-<a href="https://github.com/akashche/tzdbgen">tzdbgen</a>, and <a
+<li><a href="https://bell-sw.com/pages/iana-updater/">IANA Updater</a> and <a
 href="https://www.azul.com/products/open-source-tools/ziupdater-time-zone-tool/">ZIUpdater</a>
-are other alternatives to TZUpdater. IANA Updater's license is unclear;
-the others are licensed under the <abbr>GPL</abbr>.</li>
+are alternatives to TZUpdater. IANA Updater's license is unclear;
+ZIUpdater is licensed under the <abbr>GPL</abbr>.</li>
 <li><a href="https://github.com/MenoData/Time4A">Time4A: Advanced date and
 time library for Android</a> and
 <a href="https://github.com/MenoData/Time4J/">Time4J: Advanced date,
@@ -460,9 +475,16 @@ Java-based libraries.</li>
 time <abbr>API</abbr> for .NET</a>
 is like Joda-Time and Time4J, but for the .NET framework instead of Java.
 It is freely available under the Apache License.</li>
-<li><a href="https://en.wikipedia.org/wiki/JavaScript">JavaScript</a>-based
-compilers and libraries include:
+<li>Many modern
+<a href="https://en.wikipedia.org/wiki/JavaScript">JavaScript</a>
+runtimes support <code><abbr>tz</abbr></code> natively via the
+<samp>timeZone</samp> option of <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat"><samp>Intl.DateTimeFormat</samp></a>.
+On other runtimes, you can use one of the following.
 <ul>
+<li>The <a
+href="https://github.com/formatjs/date-time-format-timezone"><samp>Intl.DateTimeFormat</samp>
+timezone polyfill</a>
+is freely available under a <abbr>BSD</abbr>-style license.</li>
 <li><a
 href="https://github.com/kshetline/compact-time-zone-generator">CompactTimeZoneGenerator</a>
 compiles time zone data into a compact form designed for
@@ -472,6 +494,9 @@ the <abbr>MIT</abbr> license and the Apache License.</li>
 plugin for the <a href="https://momentjs.com">Moment.js</a> date
 manipulation library. It is freely available under the <abbr>MIT</abbr>
 license.</li>
+<li><a href="https://github.com/bigeasy/timezone">Timezone</a> is a
+JavaScript library that supports date arithmetic that is time zone
+aware. It is freely available under the <abbr>MIT</abbr> license.</li>
 <li><a href="https://github.com/mde/timezone-js">TimezoneJS.Date</a>'s
 <abbr>API</abbr> is upward compatible with standard JavaScript
 Dates. It is freely available under the Apache License.</li>
@@ -492,7 +517,10 @@ It is freely available under a <abbr>BSD</abbr>-style license.</li>
 <li><a href="http://pytz.sourceforge.net">pytz &ndash; World Timezone
 Definitions for Python</a> compiles <code><abbr>tz</abbr></code> source into
 <a href="https://www.python.org">Python</a>.
-It is freely available under a <abbr>BSD</abbr>-style license.</li>
+It is freely available under a <abbr>BSD</abbr>-style license.
+In code that can assume Python 3.9 or later it is superseded by
+<a href="#python-zoneinfo"><code>zoneinfo.ZoneInfo</code></a>
+and the <a href="#pypi-tzdata"><code>tzdata</code> Python package</a>.</li>
 <li><a href="https://tzinfo.github.io">TZInfo &ndash;
 Ruby Timezone Library</a>
 compiles <code><abbr>tz</abbr></code> source into
@@ -549,9 +577,6 @@ title="PHP: Hypertext Preprocessor">PHP</abbr></a>,
 <a href="https://hhvm.com"><abbr title="HipHop Virtual Machine">HHVM</abbr></a>,
 and <a href="https://www.mongodb.com">MongoDB</a>.
 It is freely available under the <abbr>MIT</abbr> license.</li>
-<li><a href="https://github.com/bigeasy/timezone">Timezone</a> is a
-JavaScript library that supports date arithmetic that is time zone
-aware. It is freely available under the <abbr>MIT</abbr> license.</li>
 <li>Tcl, mentioned <a href="#Tcl">above</a>, also contains a
 <abbr>TZif</abbr> file reader.</li>
 <li><a href="https://metacpan.org/pod/DateTime::TimeZone::Tzfile">
@@ -559,6 +584,17 @@ DateTime::TimeZone::Tzfile</a>
 is a <abbr>TZif</abbr> file reader written in Perl.
 It is freely available under the same terms as Perl
 (dual <abbr>GPL</abbr> and Artistic license).</li>
+<li>Python has a <a id="python-zoneinfo"
+href="https://docs.python.org/3.9/library/zoneinfo.html"><code>zoneinfo.ZoneInfo</code>
+class</a> that reads <abbr>TZif</abbr> data and creates objects
+that represent <code><abbr>tzdb</abbr></code> timezones.
+Python is freely available under the
+<a href="https://docs.python.org/3.9/license.html">Python Software Foundation
+License</a>.
+A companion <a id="pypi-tzdata" href="https://pypi.org/">PyPI</a> module
+<a href="https://pypi.org/project/tzdata/"><code>tzdata</code></a>
+supplies TZif data if the underlying system data cannot be found;
+it is freely available under the Apache License.</li>
 <li>The
 public-domain <a href="https://github.com/dbaron/tz.js">tz.js</a>
 library contains a Python tool that
@@ -740,7 +776,7 @@ href="https://www.geonames.org/export/web-services.html#timezone">GeoNames
 Timezone web service</a>, the <a
 href="https://developers.google.com/maps/documentation/timezone/intro">Google
 Maps Time Zone API</a>, and
-the <a href="https://timezonedb.com">Time Zone Database &amp; API</a>.
+the <a href="https://timezonedb.com/api">TimeZoneDB API</a>.
 Commercial network API access is provided
 by <a href="https://askgeo.com">AskGeo</a>
 and <a href="https://www.geogarage.com/blog/news-1/post/geogarage-time-zone-api-31">GeoGarage</a>.
@@ -892,7 +928,8 @@ href="http://sohma.armada.mil.uy/index.php/servicios/datos-astronomicos" hreflan
 <h2 id="costs">Costs and benefits of time shifts</h2>
 <p>Various sources argue for and against daylight saving time and time
 zone shifts, and many scientific studies have been conducted. This
-section summarizes reviews of scientific literature in the area.</p>
+section summarizes reviews and position statements based on
+scientific literature in the area.</p>
 <ul>
 <li>Carey RN, Sarma KM.
 <a href="https://bmjopen.bmj.com/content/7/6/e014319.long">Impact of
@@ -910,6 +947,13 @@ doi:<a href="https://doi.org/10.5547/01956574.39.2.thav">10.5547/01956574.39.2.t
 This analyzes research literature and concludes, "Electricity savings
 are larger for countries farther away from the equator, while
 subtropical regions consume more electricity because of DST."</li>
+<li>Rishi MA, Ahmed O, Barrantes Perez JH <em>et al</em>.
+<a href="https://jcsm.aasm.org/doi/10.5664/jcsm.8780">Daylight saving time:
+an American Academy of Sleep Medicine position statement</a>.
+<em>J Clin Sleep Med.</em>
+2020;<a href="https://doi.org/10.5664/jcsm.8780">10.5664/jcsm.8780</a>.
+This argues for permanent standard time due to health risks of both
+DST transitions and permanent DST.</li>
 <li>Roenneberg T, Winnebeck EC, Klerman EB.
 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6692659/">Daylight
 saving time and artificial time zones &ndash; a battle between
diff --git a/tz/tzfile.5 b/tz/tzfile.5
index 3f13563..2642978 100644
--- a/tz/tzfile.5
+++ b/tz/tzfile.5
@@ -40,25 +40,25 @@ Fifteen bytes containing zeros reserved for future use.
 Six four-byte integer values, in the following order:
 .RS
 .TP
-.I tzh_ttisutcnt
+.B tzh_ttisutcnt
 The number of UT/local indicators stored in the file.
 (UT is Universal Time.)
 .TP
-.I tzh_ttisstdcnt
+.B tzh_ttisstdcnt
 The number of standard/wall indicators stored in the file.
 .TP
-.I tzh_leapcnt
+.B tzh_leapcnt
 The number of leap seconds for which data entries are stored in the file.
 .TP
-.I tzh_timecnt
+.B tzh_timecnt
 The number of transition times for which data entries are stored
 in the file.
 .TP
-.I tzh_typecnt
+.B tzh_typecnt
 The number of local time types for which data entries are stored
 in the file (must not be zero).
 .TP
-.I tzh_charcnt
+.B tzh_charcnt
 The number of bytes of time zone abbreviation strings
 stored in the file.
 .RE
@@ -66,14 +66,14 @@ stored in the file.
 The above header is followed by the following fields, whose lengths
 depend on the contents of the header:
 .IP * 2
-.I tzh_timecnt
+.B tzh_timecnt
 four-byte signed integer values sorted in ascending order.
 These values are written in network byte order.
 Each is used as a transition time (as returned by
 .BR time (2))
 at which the rules for computing local time change.
 .IP *
-.I tzh_timecnt
+.B tzh_timecnt
 one-byte unsigned integer values;
 each one but the last tells which of the different types of local time types
 described in the file is associated with the time period
@@ -83,8 +83,8 @@ and continuing up to but not including the next transition time.
 POSIX-style TZ string described below.)
 These values serve as indices into the next field.
 .IP *
-.I tzh_typecnt
-.I ttinfo
+.B tzh_typecnt
+.B ttinfo
 entries, each defined as follows:
 .in +.5i
 .sp
@@ -99,36 +99,36 @@ struct ttinfo {
 .fi
 .sp
 Each structure is written as a four-byte signed integer value for
-.IR tt_utoff ,
+.BR tt_utoff ,
 in network byte order, followed by a one-byte boolean for
-.I tt_isdst
+.B tt_isdst
 and a one-byte value for
-.IR tt_desigidx .
+.BR tt_desigidx .
 In each structure,
-.I tt_utoff
+.B tt_utoff
 gives the number of seconds to be added to UT,
-.I tt_isdst
+.B tt_isdst
 tells whether
-.I tm_isdst
+.B tm_isdst
 should be set by
 .BR localtime (3)
 and
-.I tt_desigidx
+.B tt_desigidx
 serves as an index into the array of time zone abbreviation bytes
 that follow the
-.I ttinfo
+.B ttinfo
 structure(s) in the file.
 The
-.I tt_utoff
+.B tt_utoff
 value is never equal to \-2**31, to let 32-bit clients negate it without
 overflow.
 Also, in realistic applications
-.I tt_utoff
+.B tt_utoff
 is in the range [\-89999, 93599] (i.e., more than \-25 hours and less
 than 26 hours); this allows easy support by implementations that
 already support the POSIX-required range [\-24:59:59, 25:59:59].
 .IP *
-.I tzh_leapcnt
+.B tzh_leapcnt
 pairs of four-byte values, written in network byte order;
 the first value of each pair gives the nonnegative time
 (as returned by
@@ -142,12 +142,12 @@ The pairs of values are sorted in ascending order by time.
 Each transition is for one leap second, either positive or negative;
 transitions always separated by at least 28 days minus 1 second.
 .IP *
-.I tzh_ttisstdcnt
+.B tzh_ttisstdcnt
 standard/wall indicators, each stored as a one-byte boolean;
 they tell whether the transition times associated with local time types
 were specified as standard time or local (wall clock) time.
 .IP *
-.I tzh_ttisutcnt
+.B tzh_ttisutcnt
 UT/local indicators, each stored as a one-byte boolean;
 they tell whether the transition times associated with local time types
 were specified as UT or local time.
@@ -173,10 +173,10 @@ The
 .BR localtime (3)
 function
 normally uses the first
-.I ttinfo
+.B ttinfo
 structure in the file
 if either
-.I tzh_timecnt
+.B tzh_timecnt
 is zero or the time argument is less than the first transition time recorded
 in the file.
 .SS Version 2 format
@@ -235,7 +235,7 @@ This guideline helps obsolescent version 1 readers
 agree with current readers about timestamps within the
 contiguous subsequence.  It also lets writers not
 supporting obsolescent readers use a
-.I tzh_timecnt
+.B tzh_timecnt
 of zero
 in the version 1 data block to save space.
 .PP
diff --git a/tz/tzselect.8 b/tz/tzselect.8
index 51f751c..a1ec8d0 100644
--- a/tz/tzselect.8
+++ b/tz/tzselect.8
@@ -82,7 +82,7 @@ Output version information and exit.
 .TP
 \f3AWK\fP
 Name of a Posix-compliant
-.I awk
+.B awk
 program (default:
 .BR awk ).
 .TP
diff --git a/tz/yearistype.sh b/tz/yearistype.sh
deleted file mode 100644
index d674175..0000000
--- a/tz/yearistype.sh
+++ /dev/null
@@ -1,39 +0,0 @@
-#! /bin/sh
-: 'Determine whether year is of appropriate type (this file is obsolete).'
-
-: 'This file is in the public domain, so clarified as of'
-: '2006-07-17 by Arthur David Olson.'
-
-case $#-$1 in
-	2-|2-0*|2-*[!0-9]*)
-		echo "$0: wild year: $1" >&2
-		exit 1 ;;
-esac
-
-case $#-$2 in
-	2-even)
-		case $1 in
-			*[24680])			exit 0 ;;
-			*)				exit 1 ;;
-		esac ;;
-	2-nonpres|2-nonuspres)
-		case $1 in
-			*[02468][048]|*[13579][26])	exit 1 ;;
-			*)				exit 0 ;;
-		esac ;;
-	2-odd)
-		case $1 in
-			*[13579])			exit 0 ;;
-			*)				exit 1 ;;
-		esac ;;
-	2-uspres)
-		case $1 in
-			*[02468][048]|*[13579][26])	exit 0 ;;
-			*)				exit 1 ;;
-		esac ;;
-	2-*)
-		echo "$0: wild type: $2" >&2 ;;
-esac
-
-echo "$0: usage is $0 year even|odd|uspres|nonpres|nonuspres" >&2
-exit 1
diff --git a/tz/zdump.8 b/tz/zdump.8
index 98109ad..f3e4e4e 100644
--- a/tz/zdump.8
+++ b/tz/zdump.8
@@ -212,7 +212,7 @@ and
 output,
 .q "UT"
 denotes the value returned by
-.IR gmtime (3),
+.BR gmtime (3),
 which uses UTC for modern timestamps and some other UT flavor for
 timestamps that predate the introduction of UTC.
 No attempt is currently made to have the output use
diff --git a/tz/zic.8 b/tz/zic.8
index b57cd2b..dcd2fa3 100644
--- a/tz/zic.8
+++ b/tz/zic.8
@@ -61,15 +61,13 @@ is
 .BR slim ,
 keep the output files small; this can help check for the bugs
 and incompatibilities.
-Although the default is currently
-.BR fat ,
-this is intended to change in future
-.B zic
-versions, as software that mishandles the 64-bit data typically
+The default is
+.BR slim ,
+as software that mishandles 64-bit data typically
 mishandles timestamps after the year 2038 anyway.
 Also see the
 .B \*-r
-option for another way to shrink output size.
+option for another way to alter output size.
 .TP
 .BI "\*-d " directory
 Create time conversion information files in the named directory rather than
@@ -85,6 +83,12 @@ will act as if the input contained a link line of the form
 .ti +.5i
 .ta \w'Link\0\0'u  +\w'\fItimezone\fP\0\0'u
 Link	\fItimezone\fP		localtime
+.sp
+If
+.I timezone
+is
+.BR \*- ,
+any already-existing link is removed.
 .TP
 .BI "\*-L " leapsecondfilename
 Read leap second information from the file with the given name.
@@ -109,6 +113,12 @@ and it should not be combined with
 if
 .IR timezone 's
 transitions are at standard time or Universal Time (UT) instead of local time.
+.sp
+If
+.I timezone
+is
+.BR \*- ,
+any already-existing link is removed.
 .TP
 .BR "\*-r " "[\fB@\fP\fIlo\fP][\fB/@\fP\fIhi\fP]"
 Reduce the size of output files by limiting their applicability
@@ -224,7 +234,7 @@ or that starts with
 .RE
 .SH FILES
 Input files use the format described in this section; output files use
-.IR tzfile (5)
+.BR tzfile (5)
 format.
 .PP
 Input files should be text files, that is, they should be a series of
@@ -268,9 +278,9 @@ abbreviation must be unambiguous in context.
 A rule line has the form
 .nf
 .ti +.5i
-.ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00w\0\0'u +\w'1:00d\0\0'u
+.ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'\*-\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00w\0\0'u +\w'1:00d\0\0'u
 .sp
-Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+Rule	NAME	FROM	TO	\*-	IN	ON	AT	SAVE	LETTER/S
 .sp
 For example:
 .ti +.5i
@@ -319,12 +329,17 @@ may be used to repeat the value of the
 .B FROM
 field.
 .TP
-.B TYPE
-should be
+.B \*-
+Is a reserved field and should always contain
 .q \*-
-and is present for compatibility with older versions of
-.B zic
-in which it could contain year types.
+for compatibility with older versions of
+.BR zic .
+It was previously known as the
+.B TYPE
+field, which could contain values to allow a
+separate script to further restrict in which
+.q types
+of years the rule would apply.
 .TP
 .B IN
 Names the month in which the rule takes effect.
@@ -695,9 +710,9 @@ and for its predecessor organization, the European Communities.
 .ne 22
 .nf
 .in +2m
-.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
+.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'\*-\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
 .sp
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+# Rule	NAME	FROM	TO	\*-	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	\*-
 .sp .5
diff --git a/tz/zic.c b/tz/zic.c
index 2875b55..a902b34 100644
--- a/tz/zic.c
+++ b/tz/zic.c
@@ -81,7 +81,6 @@ struct rule {
 
 	zic_t		r_loyear;	/* for example, 1986 */
 	zic_t		r_hiyear;	/* for example, 1986 */
-	const char *	r_yrtype;
 	bool		r_lowasnum;
 	bool		r_hiwasnum;
 
@@ -133,22 +132,22 @@ struct zone {
 #if !HAVE_POSIX_DECLS
 extern int	getopt(int argc, char * const argv[],
 			const char * options);
-extern int	link(const char * fromname, const char * toname);
+extern int	link(const char * target, const char * linkname);
 extern char *	optarg;
 extern int	optind;
 #endif
 
 #if ! HAVE_LINK
-# define link(from, to) (errno = ENOTSUP, -1)
+# define link(target, linkname) (errno = ENOTSUP, -1)
 #endif
 #if ! HAVE_SYMLINK
 # define readlink(file, buf, size) (errno = ENOTSUP, -1)
-# define symlink(from, to) (errno = ENOTSUP, -1)
+# define symlink(target, linkname) (errno = ENOTSUP, -1)
 # define S_ISLNK(m) 0
 #endif
 #ifndef AT_SYMLINK_FOLLOW
-# define linkat(fromdir, from, todir, to, flag) \
-    (itssymlink(from) ? (errno = ENOTSUP, -1) : link(from, to))
+# define linkat(targetdir, target, linknamedir, linkname, flag) \
+    (itssymlink(target) ? (errno = ENOTSUP, -1) : link(target, linkname))
 #endif
 
 static void	addtt(zic_t starttime, int type);
@@ -182,7 +181,6 @@ static void	rulesub(struct rule * rp,
 			const char * typep, const char * monthp,
 			const char * dayp, const char * timep);
 static zic_t	tadd(zic_t t1, zic_t t2);
-static bool	yearistype(zic_t year, const char * type);
 
 /* Bound on length of what %z can expand to.  */
 enum { PERCENT_Z_LEN_BOUND = sizeof "+995959" - 1 };
@@ -275,8 +273,8 @@ static int		typecnt;
 ** Which fields are which on a Link line.
 */
 
-#define LF_FROM		1
-#define LF_TO		2
+#define LF_TARGET	1
+#define LF_LINKNAME	2
 #define LINK_FIELDS	3
 
 /*
@@ -313,8 +311,8 @@ static ptrdiff_t	nzones_alloc;
 struct link {
 	const char *	l_filename;
 	lineno		l_linenum;
-	const char *	l_from;
-	const char *	l_to;
+	const char *	l_target;
+	const char *	l_linkname;
 };
 
 static struct link *	links;
@@ -658,11 +656,10 @@ static const char *	lcltime;
 static const char *	directory;
 static const char *	leapsec;
 static const char *	tzdefault;
-static const char *	yitcommand;
 
 /* -1 if the TZif output file should be slim, 0 if default, 1 if the
-   output should be fat for backward compatibility.  Currently the
-   default is fat, although this may change.  */
+   output should be fat for backward compatibility.  ZIC_BLOAT_DEFAULT
+   determines the default.  */
 static int bloat;
 
 static bool
@@ -672,7 +669,7 @@ want_bloat(void)
 }
 
 #ifndef ZIC_BLOAT_DEFAULT
-# define ZIC_BLOAT_DEFAULT "fat"
+# define ZIC_BLOAT_DEFAULT "slim"
 #endif
 
 int
@@ -763,15 +760,7 @@ _("%s: More than one -p option specified\n"),
 				tzdefault = optarg;
 				break;
 			case 'y':
-				if (yitcommand == NULL) {
-					warning(_("-y is obsolescent"));
-					yitcommand = optarg;
-				} else {
-					fprintf(stderr,
-_("%s: More than one -y option specified\n"),
-						progname);
-					return EXIT_FAILURE;
-				}
+				warning(_("-y ignored"));
 				break;
 			case 'L':
 				if (leapsec == NULL)
@@ -807,14 +796,19 @@ _("%s: invalid time range: %s\n"),
 		}
 	if (optind == argc - 1 && strcmp(argv[optind], "=") == 0)
 		usage(stderr, EXIT_FAILURE);	/* usage message by request */
-	if (bloat == 0)
-	  bloat = strcmp(ZIC_BLOAT_DEFAULT, "slim") == 0 ? -1 : 1;
+	if (bloat == 0) {
+	  static char const bloat_default[] = ZIC_BLOAT_DEFAULT;
+	  if (strcmp(bloat_default, "slim") == 0)
+	    bloat = -1;
+	  else if (strcmp(bloat_default, "fat") == 0)
+	    bloat = 1;
+	  else
+	    abort(); /* Configuration error.  */
+	}
 	if (directory == NULL)
 		directory = TZDIR;
 	if (tzdefault == NULL)
 		tzdefault = TZDEFAULT;
-	if (yitcommand == NULL)
-		yitcommand = "yearistype";
 
 	if (optind < argc && leapsec != NULL) {
 		infile(leapsec);
@@ -840,11 +834,11 @@ _("%s: invalid time range: %s\n"),
 	*/
 	for (i = 0; i < nlinks; ++i) {
 		eat(links[i].l_filename, links[i].l_linenum);
-		dolink(links[i].l_from, links[i].l_to, false);
+		dolink(links[i].l_target, links[i].l_linkname, false);
 		if (noise)
 			for (j = 0; j < nlinks; ++j)
-				if (strcmp(links[i].l_to,
-					links[j].l_from) == 0)
+				if (strcmp(links[i].l_linkname,
+					links[j].l_target) == 0)
 						warning(_("link to link"));
 	}
 	if (lcltime != NULL) {
@@ -936,27 +930,27 @@ namecheck(const char *name)
    is relative to the global variable DIRECTORY.  TO can be either
    relative or absolute.  */
 static char *
-relname(char const *from, char const *to)
+relname(char const *target, char const *linkname)
 {
   size_t i, taillen, dotdotetcsize;
   size_t dir_len = 0, dotdots = 0, linksize = SIZE_MAX;
-  char const *f = from;
+  char const *f = target;
   char *result = NULL;
-  if (*to == '/') {
+  if (*linkname == '/') {
     /* Make F absolute too.  */
     size_t len = strlen(directory);
     bool needslash = len && directory[len - 1] != '/';
-    linksize = len + needslash + strlen(from) + 1;
+    linksize = len + needslash + strlen(target) + 1;
     f = result = emalloc(linksize);
     strcpy(result, directory);
     result[len] = '/';
-    strcpy(result + len + needslash, from);
+    strcpy(result + len + needslash, target);
   }
-  for (i = 0; f[i] && f[i] == to[i]; i++)
+  for (i = 0; f[i] && f[i] == linkname[i]; i++)
     if (f[i] == '/')
       dir_len = i + 1;
-  for (; to[i]; i++)
-    dotdots += to[i] == '/' && to[i - 1] != '/';
+  for (; linkname[i]; i++)
+    dotdots += linkname[i] == '/' && linkname[i - 1] != '/';
   taillen = strlen(f + dir_len);
   dotdotetcsize = 3 * dotdots + taillen + 1;
   if (dotdotetcsize <= linksize) {
@@ -972,53 +966,56 @@ relname(char const *from, char const *to)
 /* Hard link FROM to TO, following any symbolic links.
    Return 0 if successful, an error number otherwise.  */
 static int
-hardlinkerr(char const *from, char const *to)
+hardlinkerr(char const *target, char const *linkname)
 {
-  int r = linkat(AT_FDCWD, from, AT_FDCWD, to, AT_SYMLINK_FOLLOW);
+  int r = linkat(AT_FDCWD, target, AT_FDCWD, linkname, AT_SYMLINK_FOLLOW);
   return r == 0 ? 0 : errno;
 }
 
 static void
-dolink(char const *fromfield, char const *tofield, bool staysymlink)
+dolink(char const *target, char const *linkname, bool staysymlink)
 {
-	bool todirs_made = false;
+	bool remove_only = strcmp(target, "-") == 0;
+	bool linkdirs_made = false;
 	int link_errno;
 
 	/*
 	** We get to be careful here since
 	** there's a fair chance of root running us.
 	*/
-	if (itsdir(fromfield)) {
-		fprintf(stderr, _("%s: link from %s/%s failed: %s\n"),
-			progname, directory, fromfield, strerror(EPERM));
+	if (!remove_only && itsdir(target)) {
+		fprintf(stderr, _("%s: linking target %s/%s failed: %s\n"),
+			progname, directory, target, strerror(EPERM));
 		exit(EXIT_FAILURE);
 	}
 	if (staysymlink)
-	  staysymlink = itssymlink(tofield);
-	if (remove(tofield) == 0)
-	  todirs_made = true;
+	  staysymlink = itssymlink(linkname);
+	if (remove(linkname) == 0)
+	  linkdirs_made = true;
 	else if (errno != ENOENT) {
 	  char const *e = strerror(errno);
 	  fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
-		  progname, directory, tofield, e);
+		  progname, directory, linkname, e);
 	  exit(EXIT_FAILURE);
 	}
-	link_errno = staysymlink ? ENOTSUP : hardlinkerr(fromfield, tofield);
-	if (link_errno == ENOENT && !todirs_made) {
-	  mkdirs(tofield, true);
-	  todirs_made = true;
-	  link_errno = hardlinkerr(fromfield, tofield);
+	if (remove_only)
+	  return;
+	link_errno = staysymlink ? ENOTSUP : hardlinkerr(target, linkname);
+	if (link_errno == ENOENT && !linkdirs_made) {
+	  mkdirs(linkname, true);
+	  linkdirs_made = true;
+	  link_errno = hardlinkerr(target, linkname);
 	}
 	if (link_errno != 0) {
-	  bool absolute = *fromfield == '/';
-	  char *linkalloc = absolute ? NULL : relname(fromfield, tofield);
-	  char const *contents = absolute ? fromfield : linkalloc;
-	  int symlink_errno = symlink(contents, tofield) == 0 ? 0 : errno;
-	  if (!todirs_made
+	  bool absolute = *target == '/';
+	  char *linkalloc = absolute ? NULL : relname(target, linkname);
+	  char const *contents = absolute ? target : linkalloc;
+	  int symlink_errno = symlink(contents, linkname) == 0 ? 0 : errno;
+	  if (!linkdirs_made
 	      && (symlink_errno == ENOENT || symlink_errno == ENOTSUP)) {
-	    mkdirs(tofield, true);
+	    mkdirs(linkname, true);
 	    if (symlink_errno == ENOENT)
-	      symlink_errno = symlink(contents, tofield) == 0 ? 0 : errno;
+	      symlink_errno = symlink(contents, linkname) == 0 ? 0 : errno;
 	  }
 	  free(linkalloc);
 	  if (symlink_errno == 0) {
@@ -1028,24 +1025,24 @@ dolink(char const *fromfield, char const *tofield, bool staysymlink)
 	  } else {
 	    FILE *fp, *tp;
 	    int c;
-	    fp = fopen(fromfield, "rb");
+	    fp = fopen(target, "rb");
 	    if (!fp) {
 	      char const *e = strerror(errno);
 	      fprintf(stderr, _("%s: Can't read %s/%s: %s\n"),
-		      progname, directory, fromfield, e);
+		      progname, directory, target, e);
 	      exit(EXIT_FAILURE);
 	    }
-	    tp = fopen(tofield, "wb");
+	    tp = fopen(linkname, "wb");
 	    if (!tp) {
 	      char const *e = strerror(errno);
 	      fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
-		      progname, directory, tofield, e);
+		      progname, directory, linkname, e);
 	      exit(EXIT_FAILURE);
 	    }
 	    while ((c = getc(fp)) != EOF)
 	      putc(c, tp);
-	    close_file(fp, directory, fromfield);
-	    close_file(tp, directory, tofield);
+	    close_file(fp, directory, target);
+	    close_file(tp, directory, linkname);
 	    if (link_errno != ENOTSUP)
 	      warning(_("copy used because hard link failed: %s"),
 		      strerror(link_errno));
@@ -1624,16 +1621,16 @@ inlink(char **fields, int nfields)
 		error(_("wrong number of fields on Link line"));
 		return;
 	}
-	if (*fields[LF_FROM] == '\0') {
-		error(_("blank FROM field on Link line"));
+	if (*fields[LF_TARGET] == '\0') {
+		error(_("blank TARGET field on Link line"));
 		return;
 	}
-	if (! namecheck(fields[LF_TO]))
+	if (! namecheck(fields[LF_LINKNAME]))
 	  return;
 	l.l_filename = filename;
 	l.l_linenum = linenum;
-	l.l_from = ecpyalloc(fields[LF_FROM]);
-	l.l_to = ecpyalloc(fields[LF_TO]);
+	l.l_target = ecpyalloc(fields[LF_TARGET]);
+	l.l_linkname = ecpyalloc(fields[LF_LINKNAME]);
 	links = growalloc(links, sizeof *links, nlinks, &nlinks_alloc);
 	links[nlinks++] = l;
 }
@@ -1729,16 +1726,10 @@ rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
 		error(_("starting year greater than ending year"));
 		return;
 	}
-	if (*typep == '\0')
-		rp->r_yrtype = NULL;
-	else {
-		if (rp->r_loyear == rp->r_hiyear) {
-			error(_("typed single year"));
-			return;
-		}
-		warning(_("year type \"%s\" is obsolete; use \"-\" instead"),
+	if (*typep != '\0') {
+		error(_("year type \"%s\" is unsupported; use \"-\" instead"),
 			typep);
-		rp->r_yrtype = ecpyalloc(typep);
+		return;
 	}
 	/*
 	** Day work.
@@ -2500,8 +2491,6 @@ stringzone(char *result, struct zone const *zpfirst, ptrdiff_t zonecount)
 		rp = &zp->z_rules[i];
 		if (rp->r_hiwasnum || rp->r_hiyear != ZIC_MAX)
 			continue;
-		if (rp->r_yrtype != NULL)
-			continue;
 		if (!rp->r_isdst) {
 			if (stdrp == NULL)
 				stdrp = rp;
@@ -2756,14 +2745,14 @@ outzone(const struct zone *zpfirst, ptrdiff_t zonecount)
 			/*
 			** Mark which rules to do in the current year.
 			** For those to do, calculate rpytime(rp, year);
+			** The former TYPE field was also considered here.
 			*/
 			for (j = 0; j < zp->z_nrules; ++j) {
 				rp = &zp->z_rules[j];
 				eats(zp->z_filename, zp->z_linenum,
 					rp->r_filename, rp->r_linenum);
 				rp->r_todo = year >= rp->r_loyear &&
-						year <= rp->r_hiyear &&
-						yearistype(year, rp->r_yrtype);
+						year <= rp->r_hiyear;
 				if (rp->r_todo) {
 					rp->r_temp = rpytime(rp, year);
 					rp->r_todo
@@ -3054,50 +3043,6 @@ adjleap(void)
 	}
 }
 
-static char *
-shellquote(char *b, char const *s)
-{
-  *b++ = '\'';
-  while (*s) {
-    if (*s == '\'')
-      *b++ = '\'', *b++ = '\\', *b++ = '\'';
-    *b++ = *s++;
-  }
-  *b++ = '\'';
-  return b;
-}
-
-static bool
-yearistype(zic_t year, const char *type)
-{
-	char *buf;
-	char *b;
-	int result;
-
-	if (type == NULL || *type == '\0')
-		return true;
-	buf = emalloc(1 + 4 * strlen(yitcommand) + 2
-		      + INT_STRLEN_MAXIMUM(zic_t) + 2 + 4 * strlen(type) + 2);
-	b = shellquote(buf, yitcommand);
-	*b++ = ' ';
-	b += sprintf(b, "%"PRIdZIC, year);
-	*b++ = ' ';
-	b = shellquote(b, type);
-	*b = '\0';
-	result = system(buf);
-	if (WIFEXITED(result)) {
-	  int status = WEXITSTATUS(result);
-	  if (status <= 1) {
-	    free(buf);
-	    return status == 0;
-	  }
-	}
-	error(_("Wild result from command execution"));
-	fprintf(stderr, _("%s: command was '%s', result was %d\n"),
-		progname, buf, result);
-	exit(EXIT_FAILURE);
-}
-
 /* Is A a space character in the C locale?  */
 static bool
 is_space(char a)
diff --git a/tz/ziguard.awk b/tz/ziguard.awk
index e8ef49e..e27e799 100644
--- a/tz/ziguard.awk
+++ b/tz/ziguard.awk
@@ -3,6 +3,13 @@
 # Contributed by Paul Eggert.  This file is in the public domain.
 
 # This is not a general-purpose converter; it is designed for current tzdata.
+# It just converts from current source to main, vanguard, and rearguard forms.
+# Although it might be nice for it to be idempotent, or to be useful
+# for converting back and forth between vanguard and rearguard formats,
+# it does not do these nonessential tasks now.
+#
+# Although main and vanguard forms are currently equivalent,
+# this need not always be the case.
 #
 # When converting to vanguard form, the output can use negative SAVE
 # values.
@@ -28,7 +35,7 @@ DATAFORM != "main" {
   in_comment = /^#/
   uncomment = comment_out = 0
 
-  # If the line should differ due to Czechoslovakia using negative SAVE values,
+  # If this line should differ due to Czechoslovakia using negative SAVE values,
   # uncomment the desired version and comment out the undesired one.
   if (zone == "Europe/Prague" && /1947 Feb 23/) {
     if (($(in_comment + 2) != "-") == vanguard) {
diff --git a/tz/zishrink.awk b/tz/zishrink.awk
index 4e187ac..1947c7c 100644
--- a/tz/zishrink.awk
+++ b/tz/zishrink.awk
@@ -166,9 +166,6 @@ function process_input_line(line, \
   ruleline = sub(/^Rule /, "R ", line)
   zoneline = sub(/^Zone /, "Z ", line)
 
-  # SystemV rules are not needed.
-  if (line ~ /^R SystemV /) return
-
   # Replace FooAsia rules with the same rules without "Asia", as they
   # are duplicates.
   if (match(line, /[^ ]Asia /)) {
@@ -275,7 +272,6 @@ BEGIN {
   default_dep["factory"] = 1
   default_dep["northamerica"] = 1
   default_dep["southamerica"] = 1
-  default_dep["systemv"] = 1
   default_dep["ziguard.awk"] = 1
   default_dep["zishrink.awk"] = 1
 
diff --git a/tz/zoneinfo2tdf.pl b/tz/zoneinfo2tdf.pl
index e07b00c..176fce9 100755
--- a/tz/zoneinfo2tdf.pl
+++ b/tz/zoneinfo2tdf.pl
@@ -38,7 +38,7 @@ while (<>) {
     }
     $contZone = $fields[1] if @fields > 5;
   } elsif ($type eq 'rule') {
-    # Rule  NAME  FROM  TO  TYPE  IN  ON  AT  SAVE  LETTER/S
+    # Rule  NAME  FROM  TO  -  IN  ON  AT  SAVE  LETTER/S
     @fields == 10 or warn "bad rule line";
   } elsif ($type eq 'link') {
     # Link  TARGET  LINK-NAME