[Dovecot] having hell of the time converting away from UW

I just want to check and make sure not missing anything.

I'm trying to convert a customer away from UW. unfortunately, all of the mailboxes are in MBX format (my own mistake coming back to haunt me).

mailutil doesn't seem to do conversions properly. It keeps complaining about an existing copy of /mbox and only if I say to -merge append will the copy proceed.

mailsync doesn't work well with hierarchies of mailboxes. its copies the top level mailboxes but proceeds to get sick on the sub mailboxes.

I'm not sure what other tools there are to help me get out from the mbx rathole and over to the maildir wallow.

any suggestions?