Time Zone Data v. 2011m (Released 24 October 2011) file contains a line ---------------------------------------------------------------------------------- Rule Russia 1993 2010 - Mar lastSun 2:00s 1:00 S ---------------------------------------------------------------------------------- which I believe means that last change to summer time was in 2010. This is incorrect, because this (2011) year we actually have changed time on last Sunday of March (by moving clock forward) I believe that for historical purposes the rule must looks as follows ---------------------------------------------------------------------------------- Rule Russia 1993 2011 - Mar lastSun 2:00s 1:00 S ---------------------------------------------------------------------------------- On the other hand Rule --------------------------------------------------------------------------------------- Rule Russia 1996 2010 - Oct lastSun 2:00s 0 - ----------------------------------------------------------------------------------------- is correct, because Russia stopped using Daylight Savings Time switching because of a federal law "On calculation of time" signed by President Dmitry Medvedev on June 9, 2011 -- Sincerely yours, Konstantin Kivi <konst@sirena2000.ru> IT Director, Comtech-N JSC Moscow, Russia, +7-495-941-60-02