If you get Premium in AppStore, you’re eligible to get Premium Beta in Testflight
1) Choose Stop Testing in Testflight to leave public beta.
2) Install Nicegram via AppStore. (It should not Log out you from your accounts, but make a backup)
3) Buy Premium in Settings > Premium
4) Make a proof of payment - Screenshot of transaction in Appstore, video, email from Apple about purchase.
5) Send Proof of payments to Developer Bot. Add hashtag
#ngbeta and email to get an invite!
Wait until your request will be processed, you will get an email with invite.