November 2016 - tz - lists.iana.org

Tonga returns to DST on 2016-11-06
by Tim Parenti Nov. 5, 2016

Nov. 5, 2016

Tonga will observe DST from 2016-11-06 02:00 until 2017-01-15 03:00, in line with Fiji. http://mic.gov.to/news-today/press-releases/6375-daylight-saving-set-to-run… This came through as a pull request on the Github repo: https://github.com/eggert/tz/pull/19 Originally submitted patch and proposed follow-up attached. -- Tim Parenti

10 27

zic fails for soft-links-only target volume
by Tom Lane Nov. 4, 2016

Nov. 4, 2016

I received a complaint that zic recently started to fail when the target directory is on a volume that doesn't support hard links. (The complainant is using some weird VMware Fusion setup, but I think this might be true on Windows generally.) It used to go through just fine, creating symlinks instead, but as of 2016g it fails with something like ./zic: link from /home/postgres/testversion/share/timezone/US/Eastern failed: Operation not permitted It appears to me that the problem is that commit 35484e98c broke the case of linking to an existing symlink. This happened because itsdir() was modified to return 2 not 0 for a symlink, but dolink() throws an EPERM error for that, because it wasn't taught about the change. There's no reason to disallow that case, so I propose this patch: diff --git a/zic.c b/zic.c *** a/zic.c --- b/zic.c *************** dolink(char const *fromfield, char const *** 824,830 **** ** there's a fair chance of root running us. */ fromisdir = itsdir(fromfield); ! if (fromisdir) { char const *e = strerror(fromisdir < 0 ? errno : EPERM); fprintf(stderr, _("%s: link from %s/%s failed: %s\n"), progname, directory, fromfield, e); --- 824,830 ---- ** there's a fair chance of root running us. */ fromisdir = itsdir(fromfield); ! if (fromisdir < 0 || fromisdir == 1) { char const *e = strerror(fromisdir < 0 ? errno : EPERM); fprintf(stderr, _("%s: link from %s/%s failed: %s\n"), progname, directory, fromfield, e); BTW, you can test this behavior without needing to have such a volume at hand, by forcing the link() attempt to fail like this: *************** dolink(char const *fromfield, char const *** 840,845 **** --- 840,846 ---- progname, directory, tofield, e); exit(EXIT_FAILURE); } + staysymlink = true; // for testing purposes only!! link_errno = (staysymlink ? ENOTSUP : link(fromfield, tofield) == 0 ? 0 : errno); if (link_errno == ENOENT && !todirs_made) { regards, tom lane

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Why did you rename Russian zone name abbreviations
by Sergei Turchanov Nov. 3, 2016

Nov. 3, 2016

Hello! https://github.com/eggert/tz/commit/1ac038c2c3f25f7211474ae08feb6afb820 e35fe Why did you rename Russian zone name abbreviations? Can you provide a rationale for this change? This change breaks date parsing, etc... With best regards, Sergei Turchanov.

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[PROPOSED] Fix EEST typos in Palestine before 1948
by Paul Eggert Nov. 3, 2016

Nov. 3, 2016

* NEWS: Document this. * asia (Asia/Gaza, Asia/Hebron): Fix typos, to use "EEST" instead of "EET" when abbreviating summer time before 1948. --- NEWS | 8 ++++++++ asia | 4 ++-- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/NEWS b/NEWS index da5c2a5..db9f03d 100644 --- a/NEWS +++ b/NEWS @@ -1,5 +1,13 @@ News for the tz database +Unreleased, experimental changes + + Changes to past time zone abbreviations + + Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote + summer time before 1948. The old use of "EET" was a typo. + + Release 2016i - 2016-11-01 23:19:52 -0700 Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga diff --git a/asia b/asia index 67164b3..bb7534a 100644 --- a/asia +++ b/asia @@ -2616,7 +2616,7 @@ Rule Palestine 2016 max - Oct lastSat 1:00 0 - # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Gaza 2:17:52 - LMT 1900 Oct - 2:00 Zion EET 1948 May 15 + 2:00 Zion EET/EEST 1948 May 15 2:00 EgyptAsia EE%sT 1967 Jun 5 2:00 Zion I%sT 1996 2:00 Jordan EE%sT 1999 @@ -2629,7 +2629,7 @@ Zone Asia/Gaza 2:17:52 - LMT 1900 Oct 2:00 Palestine EE%sT Zone Asia/Hebron 2:20:23 - LMT 1900 Oct - 2:00 Zion EET 1948 May 15 + 2:00 Zion EET/EEST 1948 May 15 2:00 EgyptAsia EE%sT 1967 Jun 5 2:00 Zion I%sT 1996 2:00 Jordan EE%sT 1999 -- 2.7.4

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Re: [tz] Why did you rename Russian zone name abbreviations
by Paul Eggert Nov. 3, 2016

Nov. 3, 2016

On 11/02/2016 08:50 AM, turchanov(a)vl.ru wrote: > ... having "date" command output "Wed Nov 2 09:54:58 +10 2016" make > it very difficult to understand where the system is. That's fine, as the "date" command is supposed to be about *when*, not about *where*. > 2. Since the inception of tzdata Olson stated rules for abbreviated > names clearly and unambiguously > (https://github.com/eggert/tz/blob/master/Theory) That old guideline has been deprecated, as mentioned in the Theory file. > 3. I have an impression that you (un-)intentionally confuse an > abbreviated name with a GMT offset. No, the idea is that if there is no common English-language abbreviation for a time zone, tzdata uses a numeric abbreviation instead. > > if one needed a GMT offset it would have used %z-family flags. The problem is not that software needs a GMT offset. It's that software unwisely requires a time zone abbreviation even when no such abbreviation exists in common English-language practice. Although we could simply leave the abbreviation empty in this case, it's more useful to fill it with a placeholder that conveys information to users of applications that unwisely output the abbreviation as-is. > By changing the abbreviated zone name you in effect change the > original full zone name. Why didn't change Asia/Vladivostok to > Asia/+10 as well?! That wouldn't work, as Vladivostok was at +11 before 2014, and at +09 before 2011. Even in the US, where alphabetic time zone abbreviations are common, we wouldn't link America/Indiana/Petersburg to US/Eastern, because Petersburg observed Central Time before 2007. > > 5. You justify your decision to remove abbreviated names by declaring > them as an "invention". Yes. I invented these abbreviations. I didn't use any formal procedure. The (now-deprecated) guideline about them in the Theory file was written after the fact, partly in an attempt to justify them. When I invented those abbreviations, POSIX supported only alphabetic-only abbreviations. Also, I was naive about Russia: I thought that it kept time zones like the US does and that US-style alphabetic abbreviations therefore made sense for it. Nowadays, though, POSIX allows numeric abbreviations, and I know more about Russian practice. From an English-speaking point of view, abbreviations like VLAT are misleading because they imply that there is a time zone at a fixed offset from UTC called "VLAT", which is how abbreviations like "PST", "GMT", and "CET" work. However, abbreviations like "VLAT" do not correspond to fixed UTC offsets, and this is something that English-speakers are typically not expecting or accustomed to. So even if "VLAT" were widely used by Russian speakers, it would still be dubious as an abbreviation in English-language tzdata. I agree that the current situation could be improved, and that there could be a better way to localize time zone abbreviations. I expect this is an effort that should be under the CLDR umbrella, as they're the localization gurus. It may be that we need a better API for getting at localized abbreviations. Certainly the tzcode strftime.c is incomplete here, as it doesn't even support Russian month names, much less genitive-case Russian dates (does CLDR handle that correctly? if not, it should...).

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Latest tzdata2016
by Raymond Kumar Nov. 3, 2016

Nov. 3, 2016

Hi I would like to have a latest patch for tzdata. There were some changes performed on Tonga time zone and we need this patch as Tonga DST is from this week 5th November and we would like to apply this patch on systems. Thanks, Raymond Kumar Head of Billing & Products +6797015315 ________________________________ Notice of Confidentiality: The information contained in this communication is intended solely for the use of the individual or entity to whom it is addressed and others authorized to receive it. It may contain confidential or legally privileged information. If you are not the intended recipient you are hereby notified that any disclosure, copying, distribution or taking any action in reliance on the contents of this information is strictly prohibited and may be unlawful. If you have received this communication in error, please notify us immediately by responding to this email and then delete it from your system.

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[tz-announce] 2016i release of tz code and data available
by Paul Eggert Nov. 2, 2016

Nov. 2, 2016

The 2016i release of the tz code and data is available. It reflects the following changes, which were either circulated on the tz mailing list or are relatively minor technical or administrative changes: Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga reintroduces DST on 2016-11-06. Changes to future time stamps Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on 2017-01-15 at 03:00. Assume future observances in Tonga will be from the first Sunday in November through the third Sunday in January, like Fiji. (Thanks to Pulu ʻAnau.) Switch to numeric time zone abbreviations for this zone. Changes to past and future time stamps Northern Cyprus is now +03 year round, causing a split in Cyprus time zones starting 2016-10-30 at 04:00. This creates a zone Asia/Famagusta. (Thanks to Even Scharning and Matt Johnson.) Antarctica/Casey switched from +08 to +11 on 2016-10-22. (Thanks to Steffen Thorsen.) Changes to past time stamps Several corrections were made for pre-1975 time stamps in Italy. These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and Europe/Vatican. First, the 1893-11-01 00:00 transition in Italy used the new UT offset (+01), not the old (+00:49:56). (Thanks to Michael Deckers.) Second, rules for daylight saving in Italy were changed to agree with Italy's National Institute of Metrological Research (INRiM) except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian Inglis, and Michael Deckers): The 1916-06-03 transition was at 24:00, not 00:00. The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at 00:00, not 01:00. The 1917-09-30 and 1918-10-06 transitions were at 24:00, not 01:00. The 1944-09-17 transition was at 03:00, not 01:00. This particular change is taken from Italian law as INRiM's table, (which says 02:00) appears to have a typo here. Also, keep the 1944-04-03 transition for Europe/Rome, as Rome was controlled by Germany then. The 1967-1970 and 1972-1974 fallback transitions were at 01:00, not 00:00. Changes to code The code should now be buildable on AmigaOS merely by setting the appropriate Makefile variables. (From a patch by Carsten Larsen.) Here are links to the release files: ftp://ftp.iana.org/tz/releases/tzcode2016i.tar.gz ftp://ftp.iana.org/tz/releases/tzdata2016i.tar.gz ftp://ftp.iana.org/tz/releases/tzdb-2016i.tar.lz The files are also available via HTTP as follows: http://www.iana.org/time-zones/repository/releases/tzcode2016i.tar.gz http://www.iana.org/time-zones/repository/releases/tzdata2016i.tar.gz http://www.iana.org/time-zones/repository/releases/tzdb-2016i.tar.lz As usual, links to the latest release files are here: http://www.iana.org/time-zones/repository/tzcode-latest.tar.gz http://www.iana.org/time-zones/repository/tzdata-latest.tar.gz http://www.iana.org/time-zones/repository/tzdb-latest.tar.lz ftp://ftp.iana.org/tz/tzcode-latest.tar.gz ftp://ftp.iana.org/tz/tzdata-latest.tar.gz ftp://ftp.iana.org/tz/tzdb-latest.tar.lz Each release file has a GPG signature, which can be retrieved by appending ".asc" to the above URLs. Copies of these signatures are appended to this message. This release corresponds to commit 9774c293b7ea6ec7be851cb0b2a0807840e6793e dated 2016-11-01 23:19:52 -0700 and tagged '2016i' in the experimental github repository at <https://github.com/eggert/tz>. Here are the SHA-512 checksums for the release files: 93be791491a76f9d489f4bce8b392b2af6bdfb9a21f7efb7c6948da5c27db9782f7a725dd53d755e9488de000a4af5b75de650e7dac8c01ef8fbbd2719f9cd07 tzcode2016i.tar.gz 801059f43c91798cf69fb2ae77c1ffab8d06987325081511d573febde19ae423e7432c2b65c7c256077bbdb1b359e010302955786e18f2697bb263c4e0f1cc91 tzdata2016i.tar.gz 7e71521ed61ae2aca941b88c6308f3e6f90dc3356fef323c15b6907aefb827c11d19e2516b07c205f0365be736fbce3023bb9717a6a6a50964584b3f7b3baa81 tzdb-2016i.tar.lz Here are the GPG checksums for the release files: -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJYGYaQAAoJEO2X6Q5iqn402R0P/3AMlJCx/gABznqJhidPNCph dQikzUgHZaYyMNHdUYmxVV8gxjopMrFhKdJPalnb2mUcekAthc6h13TpDFvo0xKJ plBDNvA1hFXuHgLBrEJbtABFEIWLplfSJREAlvu41/OdtmXKnKINcg9pVD9Xm2hT TRWQVTXEc3wOFxGctfefXfGmyGK4Fc1UI2dYM8sS22pJrXeFrHZmJOfxL7r06qtM TSyDlL2o43V1i3IQVhwgkTKE8Q8cxOZVGqFjUu4urWGYIyK4x2ap0ZYaEqLeYBgx qzdTrINYIiSG5Qr9g/Uf4hNQ0fH2Vif+GaJOVCAJet+DL3Rj32hKLJC0x3L4+xx3 KmlYGOGh869kWu8h2qu/2ac4b0657SchgCx9BrZZ5m/bVYQeqOKLU5b2g/WLILv8 Tj0UPQqB6Lj0wzdSwUZN8V20nUaaQmoDpMDrt8/oZ5pwGCUSigLPPINu4Po6Iiyk leHfnAZj28xEoeJI77O2DJ4HO9nz8XvtOQUMxvixLvcIiLhUpeKFwrF+B5TXtOzZ pQ3M/pON7DytxM36ykArTwj7Pct+uwOJbkIVUIAdVE/cXmtlLR2f1VC6DQhO8x4N aaeKIXEYVioWCDWETi+OUWUyd+A2Fn0ykls6oGwhCdeHAeTRINsTesoBoQbh6/i4 1f6Fg4z5hNUZZyYfwp/j =V12P -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJYGYaQAAoJEO2X6Q5iqn40uykQAIlYwx+ZXwTh7f5GncBFvbkB A+zrwU2qFqLqy2ikyccUcs6LXbdxw5q9xb1pT1AEt7nKGqK2n7EF4TtbnYTLPijr e/A9WWzDozBDl4ExyG8TH/Zz8KcwPhbX9oq6+he7KYN2FwLwj/JEKWfp7esAsjqa CvMFGElUQMnRtv6PGfjYifU+5BYf0K6VhJ+iPpfb7NHiAEMBztt0mIlWKNB/hxuD 4ucWsr+k32NdlKgfxTDwfcEq9hd4wMmYfaTmxi1JUYmZ2UUr/ofns5VNYn4LKYz4 l7tN5cITS01fbcb/lYMMdeKnurxpNXvhjFiYJvCUGo1/ZOxBrUSF76JvjqLhKECw tD69X4zWEuAdgFIJfnpK7PAquW9YpkYhyeGLGvYQxIQTZVTRnyxlVJGFMinD2XFT /yjDMZDsdGReN0oTkxJ/vTnh45lNezBs9JJ2Quuxe/ZvT6ujRqK0yGSReYhpiKzz 6CS9PS5Ojgo0mvKJszccKgxu8nYAL3Odfr8CuVnWPPbhHBzM2TKQU9aXeJa7Nd6t MZZD6fp2qEFUd9qGRdz3E8UYSGCIYJfm85lx/DjxHiLQWdglfvwdGx4b3fsbCoKy iOUChS+12qShRHreKcNOnkaRe18J+5/unN3uh6aJoXmoCGbjcYjSIl5kF5Mb/iaN Fb0MCCcov7527m9ZVHNp =O/rc -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJYGYaQAAoJEO2X6Q5iqn40P7YQALUKbftldhSEHGo7WcQFBqO4 oKF3KbnbxgU1kKS3sMPjM2WfFbPSGotBZwAmRiJSuAhCQuT7IOdzlnH0A+gNHv1F SOz/w7qJPDPOze9hxy9oVLHK7kz2NsIqLoCQUKb48Bo/6CakhQXf0Bh/OgsAYCUe DtXk7AEJvRRb3V5z448cUqjPCW55zIEdiG7hC23rRQr4ETnCU5rfMXDLGD176NQl wm8uWGClqqPIFG1T5G9I3yKUZemlTjPi6dCRFWtCzGM1yKhCXceAA2OBx//LG8K2 nOhDwUwNMXdh7hRPMQQq/tbP1etkeNopMCQU+z0+eNGPR26IsWL3ouEAKO0j6DKy 1NoykCXjEZV0V8dNxU0mPWZ+oESbxgSML3FDlMPsuDar40eTTLpz3kg7aAb+fxTB FgL+HD3LPalOfIu/BM494EwggCsM3waAjRvhASNguWCOxGQVDQTVQoASpyPlyw2X d3Sdpot0o0ed998lDEFAvBOILW19lTDxgHYBKMTK8McE/UW/UGFHliH1oxFz+H1g kyMlJ7LWYaFN+G1p4qo6+LHddUa4hl50x8QYv3FZe6q5UOGEB7qMQq/40mMtFQWU yuvL/bmPqeYgsp3slZM9t/trzxwIDYe+S4508tn+6zQ0Ddg37COXoLvozGFI8g7R cqjLOztN8+7qZcotVR88 =BqkM -----END PGP SIGNATURE----- _______________________________________________ tz-announce mailing list tz-announce(a)iana.org https://mm.icann.org/mailman/listinfo/tz-announce

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[PROPOSED PATCH] Cyprus is splitting into two time zones
by Paul Eggert Nov. 2, 2016

Nov. 2, 2016

Add a zone Asia/North_Nicosia for North Cyprus. * NEWS: Document this. * asia, zone.tab, zone1970.tab (Asia/North_Nicosia): New zone. --- NEWS | 5 +++-- asia | 11 ++++++++++- zone.tab | 3 ++- zone1970.tab | 3 ++- 4 files changed, 17 insertions(+), 5 deletions(-) diff --git a/NEWS b/NEWS index a4af3b2..64233bf 100644 --- a/NEWS +++ b/NEWS @@ -5,8 +5,9 @@ Unreleased, experimental changes Changes to future time stamps Turkey switched from EET/EEST (+02/+03) to permanent +03, - effective 2016-09-07. (Thanks to Burak AYDIN.) Use "+03" rather - than an invented abbreviation for the new time. + effective 2016-09-07. (Thanks to Burak AYDIN.) Northern Cyprus + followed suit the next day, which creates a zone Asia/North_Nicosia. + Use "+03" rather than an invented abbreviation for the new time. New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52. (Thanks to Tim Parenti.) diff --git a/asia b/asia index e285326..4462cd4 100644 --- a/asia +++ b/asia @@ -773,6 +773,12 @@ Zone Asia/Macau 7:34:20 - LMT 1912 Jan 1 # Cyprus # # Milne says the Eastern Telegraph Company used 2:14:00. Stick with LMT. +# IATA SSIM (1998-09) has Cyprus using EU rules for the first time. +# +# From Paul Eggert (2016-09-09): +# Yesterday's Cyprus Mail reports that Northern Cyprus followed Turkey's +# lead and switched from +02/+03 to +03 year-round. +# http://cyprus-mail.com/2016/09/08/two-time-zones-cyprus-turkey-will-not-tur… # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Cyprus 1975 only - Apr 13 0:00 1:00 S @@ -788,7 +794,10 @@ Rule Cyprus 1981 1998 - Mar lastSun 0:00 1:00 S Zone Asia/Nicosia 2:13:28 - LMT 1921 Nov 14 2:00 Cyprus EE%sT 1998 Sep 2:00 EUAsia EE%sT -# IATA SSIM (1998-09) has Cyprus using EU rules for the first time. +Zone Asia/North_Nicosia 2:13:27 - LMT 1921 Nov 14 + 2:00 Cyprus EE%sT 1998 Sep + 2:00 EUAsia EE%sT 2016 Sep 8 + 3:00 - +03 # Classically, Cyprus belongs to Asia; e.g. see Herodotus, Histories, I.72. # However, for various reasons many users expect to find it under Europe. diff --git a/zone.tab b/zone.tab index bf1bb71..15989f4 100644 --- a/zone.tab +++ b/zone.tab @@ -152,7 +152,8 @@ CU +2308-08222 America/Havana CV +1455-02331 Atlantic/Cape_Verde CW +1211-06900 America/Curacao CX -1025+10543 Indian/Christmas -CY +3510+03322 Asia/Nicosia +CY +3510+03322 Asia/Nicosia Cyprus (most areas) +CY +3511+03322 Asia/North_Nicosia North Cyprus CZ +5005+01426 Europe/Prague DE +5230+01322 Europe/Berlin Germany (most areas) DE +4742+00841 Europe/Busingen Busingen diff --git a/zone1970.tab b/zone1970.tab index 49f0b0b..efe27b1 100644 --- a/zone1970.tab +++ b/zone1970.tab @@ -144,7 +144,8 @@ CU +2308-08222 America/Havana CV +1455-02331 Atlantic/Cape_Verde CW,AW,BQ,SX +1211-06900 America/Curacao CX -1025+10543 Indian/Christmas -CY +3510+03322 Asia/Nicosia +CY +3510+03322 Asia/Nicosia Cyprus (most areas) +CY +3511+03322 Asia/North_Nicosia North Cyprus CZ,SK +5005+01426 Europe/Prague DE +5230+01322 Europe/Berlin Germany (most areas) DK +5540+01235 Europe/Copenhagen -- 2.7.4

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Re: [tz] Cyprus is splitting into two time zones
by Evan Siroky Nov. 2, 2016

Nov. 2, 2016

Regarding the buffer zone, according to this Wikipedia Article (https://en.wikipedia.org/wiki/United_Nations_Buffer_Zone_in_Cyprus) "Turkish forces built a barrier on the zone's northern side". So maybe everything north of the buffer zone would be considered Asia/Famagusta and the whole buffer zone plus south of the buffer zone would be Asia/Nicosia.

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www.timeanddate.com provides different data
by Gintare Statkute Nov. 2, 2016

Nov. 2, 2016

Dear sir/madam On this website i find the following data: https://www.timeanddate.com/time/zone/uk/london 2015Sun, 29 Mar, 01:00GMT <https://www.timeanddate.com/time/zones/gmt> → BST <https://www.timeanddate.com/time/zones/bst>+1 hour (DST start)UTC+1h Sun, 25 Oct, 02:00BST <https://www.timeanddate.com/time/zones/bst> → GMT <https://www.timeanddate.com/time/zones/gmt>-1 hour (DST end) <https://www.timeanddate.com/news/time/europe-dst-end-2015.html>UTC 2016 Sun, 27 Mar, 01:00GMT <https://www.timeanddate.com/time/zones/gmt> → BST <https://www.timeanddate.com/time/zones/bst>+1 hour (DST start) <https://www.timeanddate.com/news/time/europe-starts-dst-2016.html>UTC+1h Sun, 30 Oct, 02:00BST <https://www.timeanddate.com/time/zones/bst> → GMT <https://www.timeanddate.com/time/zones/gmt>-1 hour (DST end) <https://www.timeanddate.com/news/time/eu-debate-dst.html>UTC 2017 Sun, 26 Mar, 01:00GMT <https://www.timeanddate.com/time/zones/gmt> → BST <https://www.timeanddate.com/time/zones/bst>+1 hour (DST start)UTC+1h Sun, 29 Oct, 02:00BST <https://www.timeanddate.com/time/zones/bst> → GMT <https://www.timeanddate.com/time/zones/gmt>-1 hour (DST end)UTC 2018 Sun, 25 Mar, 01:00GMT <https://www.timeanddate.com/time/zones/gmt> → BST <https://www.timeanddate.com/time/zones/bst>+1 hour (DST start)UTC+1h Sun, 28 Oct, 02:00BST <https://www.timeanddate.com/time/zones/bst> → GMT <https://www.timeanddate.com/time/zones/gmt>-1 hour (DST end)UTC 2019 Sun, 31 Mar, 01:00GMT <https://www.timeanddate.com/time/zones/gmt> → BST <https://www.timeanddate.com/time/zones/bst>+1 hour (DST start)UTC+1h Sun, 27 Oct, 02:00BST <https://www.timeanddate.com/time/zones/bst> → GMT <https://www.timeanddate.com/time/zones/gmt>-1 hour (DST end)UTC As you can see, the Europe/London time change rule is different every year . But i can not find this information on yor data distribution. https://www.iana.org/time-zones For europe, london you give: # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Europe/London -0:01:15 - LMT 1847 Dec 1 0:00s 0:00 GB-Eire %s 1968 Oct 27 1:00 - BST 1971 Oct 31 2:00u 0:00 GB-Eire %s 1996 0:00 EU GMT/BST Maybe i do not understand how to use your data? I put the question on stackoverflow: http://stackoverflow.com/questions/40360032/iana-internet-assigned-numbers-… regards, -- *Gintare Statkute*

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