I had an issue where my logs were saying "IMAP polling skipped: provider not configured" when checking IMAP emails after upgrading to the latest version. I thought I would post the solution I found in case anyone else has the same.
Firstly I updated my cron scripts as per https://docs.itflow.org/cron#cron_scripts_of_v2501 due to the deprecated cron scripts as it said in the changelogs. (https://forum.itflow.org/d/2268-v2510-spooky-october-release)
That didnt fix it, so then I went to Settings -> Mail and pressed Save under "IMAP Mail Settings (For Monitoring Ticket Inbox)". I also pressed save on all the others, which probably wasnt needed.
That fixed it.
This might be common knowledge, but it took me a little while to work out, so I thought it might help others.