Second this. Will PTB be async-only and if I don't know async I won't be able to write bots on PTB?

If it will be async-only, why should one choose PTB over aiogram?

change our code to async style or it will optional to switch

you dont have to change "your" code to async, all calls for this library have to be though. That is what the seventh paragraph talks about.

If it will be async-only, why should one choose PTB over aiogram?

we provide a very different interface, a bigger documentation (as far as I can see), well integrated jobs. But we won't stop you from using aiogram ofc, do what makes you happy :D

if a callback doesn't make any asyncio calls and can be defined as non-async, I guess it's reasonable to try and support that. I.e. do something like

if inspect.iscoroutinefunction(callback):
    return await callback(…)
return callback(…)

in Handler.handle_update

Hi, thanks for the comment :) We haven't discussed the details of how tg.ext will change yet, but IMO that's pretty much what should happen, i.e. the run_async parameter should pretty much do the same in v14. See also the third § here #2288 (comment) :)

Why is asynchronous programming not beginner friendly? If you dont want to explain why you have to write async before functions and call methods with await, don't? Thats literally the only change one has to make in non complex/beginner code. Apart from updater/dispatcher now being even easier to understand because there is one application which holds everything together.

Hi, thanks for the concern. We decided not to offer synchronous support since we found out that simply adding an async/await to your callbacks does not make it harder for beginners (among other reasons). One doesn't need to have a deep understanding of asyncio to start writing bots or learning python. You could tell the students that await calls async functions for now.

The switch to asyncio is very advantageous for making bots (see OP) which is the main selling point here.

Besides, as poolitzer mentioned, there are many other parts of the code which were simplified and have become easier to understand too.
However that being said, we are still offering support for v13.x versions (API updates and critical bugs) so you can also continue using that for teaching.

Why is asynchronous programming not beginner friendly?

Well, because it’s a new concept to grasp — and not the basic one (you could easily never touch asyncio if you’re not a professional)

If you dont want to explain why you have to write async before functions and call methods with await, don't

Yeah, that’s how to teach programming without teaching to understand :(
When you just start writing code in Python, everything seems very simple and it motivates to continue. You understand everything that’s happening in your code, each symbol having its own meaning — and when you start seeing the module you’ve never seen before (and it adds strange words to all the functions somehow and the logic is not linear anymore), it makes you not want to learn that anymore. For instance, Django is bad for beginners (at least in my experience), but Flask and PTB v13.x are great.

However that being said, we are still offering support for v13.x versions (API updates and critical bugs) so you can also continue using that for teaching

I’ll probably go that way for the most of the students, but will leave v20.x and asyncio as the second level there (because at the simple level you don’t really need to think deeply about what’s happening there)

Thank you for your replies :)