To downgrade an Apple device you need to use TestFlight. Use this link on your Apple device: https://testflight.apple.com/join/uQhfGyvn (Source thread: https://bbs.zwoastro.com/d/23618-apology-and-update-on-version-24-issues-stable-version-233-available). NOTE: Not 100% sure if this still works, though.
To downgrade an Android device read this: https://bbs.zwoastro.com/d/18885-how-to-downgraderollback-asiair-app-firmware-with-android
Remember:
For Apple - to disable auto updates - you can only do this for all apps via the App Store app. However, if you install the ASIAIR App via TestFlight, I think you can disable app updates for just the ASIAIR App in TestFlight.
For Android - to disable auto updates - you go to the Play Store app, then go to the ASIAIR App product page, tap on the triple dot menu in the top right of the screen, then untick the auto update box.