that’s helpful - if we trust that filter worked (and I don’t have any reason to doubt it) then only messages from 2022-03-08 to present might have been subject to silent and arbitrary deletion. I have a full mailbox backup from 2020-05 and from 2021-08, the former from before installing delta chat at all, the latter from before 1.27.0. If I find any evidence of older mail being deleted, I’ll report it as it might help others who also suffered mail destruction.