Hello, I am currently developing a C++ time-zone database parser, building on top of Howard Hinnant's work. I am writing thorough checks. One Zone check that I am experimenting with is: *If the FORMAT field contains either a "%s" or a '/' then the RULES field must contain a named rule.* However line 3840 of the asia file in: https://data.iana.org/time-zones/releases/tzdata2021e.tar.gz fails this check, as highlighted in yellow in the table below. # Tajikistan # From Shanks & Pottenger. # Zone NAME STDOFF RULES FORMAT [UNTIL] Zone Asia/Dushanbe 04:35:12 - LMT 1924 May 2 5:00 - +05 1930 Jun 21 6:00 RussiaAsia +06/+07 1991 Mar 31 2:00s 5:00 1:00 +05/+06 1991 Sep 9 2:00s 05:00 - +05 My guess is that '+05/+06' should be '+05'. I may well be wrong. Could you let me know either way? If you are interested, I have found a few other bits and pieces where the data files are in slight variance with the documentation but are not show-stoppers. Most of these occur in the very early releases. (I am testing every database available on https://data.iana.org/time-zones/releases/) Regards Nick Deguillaume +44 75 2828 6473