- updated to 1.2.11
    - mbox: Message header reading was unnecessarily slow. Fetching a huge
        header could have resulted in Dovecot eating a lot of CPU. Also
        searching messages was much slower than necessary.
    - maildir: Reading uidlist could have ended up in an infinite loop.
    - IMAP IDLE: v1.2.7+ caused extra load by checking changes every
    0.5 seconds after a change had occurred in mailbox