The Telegram X project features apps written from scratch, with an entirely new code base and without all the legacy components that their older apps have accumulated through the years. The goal of Telegram X is to reinvent Telegram and explore new frontiers in speed, ease of use, quality of animations and all other aspects.
First of all, the current Telegram X apps are experimental. The stable clients remain Telegram for Android and Telegram for iOS. The following issues and missing functions may or may not be up to date.