See the “ACL handling bugs” message for more details about the ACL merging bug.
* acl: Fixed the logic of merging multiple ACL entries. Now it works as documented, while previously it could have done slightly different things depending on the order of the entries. * acl: Don't give admin rights to all owner mailboxes. This was originally done to make sure that mailbox owner couldn't accidentally remove their own admin rights. But this is already prevented by SETACL command, so it's not necessary. Also sysadmin may have intentionally removed some admin rights from some mailboxes (especially when using symlinked shared mailboxes). - Maildir: Fixed potential "Duplicate file entry" in dovecot-uidlist file errors. - Maildir: Avoid unnecessary uidlist recreation during mail delivery. - imap: When SELECT fails, it didn't close the previous mailbox. - Dovecot master process could have died if it got SIGCHLD signals very rapidly while it was trying to log. This could have happened for example if a lot of imap/pop3 sessions disconnected at the exact same time.