Oh that "This update is being rolled out gradually" refers to the payment becoming available? I thought it was about the text it belongs with, speaking of "over 100 fixes and optimizations" and other stuff, and that the subscription was available now (since "Today we're launching <star> Telegram Premium" in bold up top). Confusing, but thanks for the reply!

If you have an iOS device, you can force the app store to refresh and update Telegram. Then once updated, in the app under settings, you can select Telegram Premium and pay with Apple Pay

Not on iOS but thanks!

I wonder if it'll come to the f-droid version, but otherwise I'm still using the official desktop client so it should be possible there.