Hello, last time I used data from unicode.org which use time zone information from your time zones database. I found one moment: RU +4457+03406 Europe/Simferopol MSK+00 - Crimea Timezone "Europe/Simferopol" (and Simferopol city itself) should belong to Ukraine (UA), not Russia (RU). Crimea, as temporary occupied area in all international documents states as ukrainian territory. More details can be found here: http://usa.mfa.gov.ua/en/legal_aspects https://en.wikipedia.org/wiki/United_Nations_General_Assembly_Resolution_68/... It's not political position or some other sort of things to argue with. In this case one country (Russia) temporarily occupied part of another country (Ukraine), but no countries except Russia itself treat it legal. So UN with most votes (countries) decided to treat Crimea still as a part of Ukraine and this position should be used for all international materials and communications. Please make changes to your data, returning Europe/Simferopol to correct country. Otherwise ukrainian government (if officially notified) will insist on making changes in documents in juridical manner (there were some precedents with Coca-Cola company, french national maps agency and several more). Thanks in advance, will be glad to receive a responce!