IMAP Push Not Working on v22 on Android 17

New Pixel 11 Pro, migrating from K-9 Mail v. 6.603 on Pixel 8 where everything worked fine. Used Google Setup, which transferred everthing from Pixel 8 to Pixel 11 Pro. Everything seems to have transferred fine, including multiple identities on all accounts. Entered K-9 Mail passwords for all email accounts when prompted during the transfer. Sending works, manually checking mail works, but no push. Double-, triple-, and quadruple-checked (and more) incoming server settings, and Push is indeed enabled on Inbox.

Tested many, many times, and v22 on Pixel 11 never gets push, yet Pixel 8 push works every time. This version has no option to see Folder Classes, so I am stuck there.

I’ve been using K-9 Mail for years, so this is very frustrating. Is there a bug here? Can I revert back to v6.603 on the Pixel 11 Pro somehow?

Thank you.

It suddenly started working. Although I previously tried it before my making my initial post, it may have been solved by changing Optimization to Unrestricted under Settings/Apps/K-9 Mail/App battery usage/Allow background usage, then waiting a while for the change to take effect.