I've been using Telegram for at least 5-6 years.. Now I downloaded latest app, using same phone, same Sim card and same phone number, however it forced me to create new account, all older chats, groups, contacts are gone. Lost all of that information. Update: also tried to open desktop app, it had all my history for a second and then everything disappeared and said that app is outdated, forced to update.. All gone as well.