Re: Help: Sharing IMAP folder from a mdbox mailbox to a maildir mailbox

On Sep 5, 2025, at 13:05, Aki Tuomi <aki.tuomi@open-xchange.com> wrote:

Running mixed system with shared folders is going to indeed be very difficult and I would strongly recommend against it. It sounds to me that you should migrate to new server with new config and just one mailbox format first.

Hi Aki,

Thanks for helping.

We migrated some accounts with large mailboxes to mdbox for better performance, hence we have mixed mailbox formats on same server.

1. Would you mind sharing what the difficulties are in this case?
2. Can we get it work if userdb returns required information?
3. Does it mean user shared mailbox only works with maildir format mailbox?
4. Does it work with Dovecot 2.3? I didn't try it before with 2.3, but since we have mixed mailbox formats in production, i tested it with 2.4 while migrating and experiencing this issue.