Dear Maintainer, this bug is related to bug #1040708, where an issue with database scheme for postgresql was resolved in package version mailman3/3.3.8-3. That version never landed in stable, despite the bug was tagged bookworm (actual stable), so using mailman3 with postgres doesn't work out of the box in stable/bookworm, as the service refuses to start. I don't know if this is related with a transition occurring with mailman3 packages, but I think it is worth to leave the version 3.3.8-3 to reach the stable repository. Thanks Paolo