Important thing I forgot to mention in the change logs.

Starting 0.21.6.1100 beta, it does not matter whether you have trouble connecting to Telegram from your region, proxy is down, etc. Notifications in Telegram X should work anyway almost the same way when there're no connection issues. (unless Telegram servers will be down, but that's another story)

While it's still in beta, it seems to be working good. Just make sure Telegram X and Google Play Services are up-to-date.

For proxy I personally recommend @proxyme.