http://dovecot.org/releases/1.2/alpha/dovecot-1.2.alpha1.tar.gz http://dovecot.org/releases/1.2/alpha/dovecot-1.2.alpha1.tar.gz.sig
This is the only v1.2.alpha announcement I'm going to send to dovecot-news list. Next announcement will be for either v1.2.beta1 or v1.2.rc1.
I'm hoping that v1.2 stabilizes pretty soon. There are no huge changes like there were in 0.99->1.0 or 1.0->1.1, so most of the bugs are probably related to new features. I'm already running v1.2 myself and it's gone through heavy stress testing with my imaptest tool, so I'm expecting it to be stable enough for real world testing with not-all-that-important servers. It's safe to jump between v1.1 and v1.2 at any time or even have them concurrently accessing the same mailboxes.
Dovecot v1.2 has a lot of new IMAP extensions implemented. The biggest change comes from CONDSTORE extension which adds a new concept of "modification sequences" (modseq for short). Each message has a modseq that increases whenever a flag is changed or when the message is expunged. The client can keep track of the highest seen modseq and request only changes done since the modseq. See QRESYNC (RFC 5162) for more information. Dovecot starts keeping track of the modseqs only when the first "CONDSTORE/QRESYNC enabling command" is executed. Before that no disk space is used for modseqs. When modseqs are enabled dovecot.index file uses 8 bytes per message more space.
Other implemented IMAP extensions are: ESEARCH, SEARCHRES, WITHIN, ID and CONTEXT=SEARCH.
Added thread indexes to optimize IMAP THREAD command. Only the first half of threading is currently optimized, the rest will hopefully follow later.
Added a non-standard X-REFERENCES2 threading algorithm where threads are sorted by their latest message instead of the thread root message. There is also no base subject merging. This may be renamed and become part of SEARCH=INTHREAD extension some day.
SEARCH=INTHREAD is still a draft, but the INTHREAD search key is already implemented by Dovecot v1.2. This is mostly useful with virtual mailboxes.
Virtual mailboxes: http://wiki.dovecot.org/Plugins/Virtual
Then there are also some internal API changes which will make some things easier. For example lib-storage now allows handling multiple different users at the same time.