Telegram X is a Telegram app client written from scratch in the programming language of Swift. Telegram arranged a competition between the developers, resulting in a faster and less energy-intensive version of the messenger.
According to the developers, Telegram X allows them to quickly test new approaches and technologies, which in turn, accelerates the perfection of Telegram.
The question is whether this is an official client. Well, after a series of disputes, it turned out it was the official one. Although Telegram X is not being worked on by the same development team as of the usual Telegram, the "X" team, however, was the developer of the Telegram desktop version for MacOS. The evidence is out there! <wink> AppStore <wink>