I agree that breaking an existing profile when upgrading with no way of recovering it after downgrading is very user-unfriendly. That said it's an upstream decision, and it was documented in the upstream release notes: https://www.thunderbird.net/en-US/thunderbird/91.0/releasenotes/.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1946606 Title: thunderbird 91 does not support movemail To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/thunderbird/+bug/1946606/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs