> Could you please tell me / do you know if those dovecot* files have to be > also backed / archived?
IIRC the plain files from cur/ and new/ should suffice. You can try it: create a new IMAP folder, then close your mail app. Copy some mail files from another cur/ to this imap folder's cur/ directory. Reopen your mail app and see if new mails are fetched. Best regards Gerald
