galactique Where can I find Asiair Pro user documentation that is up to date?
Have you taken a look at this?
https://www.yuque.com/zwopkb/asiair
Not from ZWO, but apparently blessed by them.
Where can I find announcements of new s/ware upgrades?
Software and firmware updates are posted to one of the pages of the above documentation:
https://www.yuque.com/zwopkb/asiair/release-log
You can turn on iPadOS software update Notification when new software is available at the Apple App Store. Likewise, you can turn the TestFlight notification on to be notified of Beta releases. (I usually get sterophonic beeps from my 5 iOS/iPadOS devices when a new ASIAIR beta arrives :-).
Chen