If you've been waiting for a fully stable release after the recent cache file troubles in v2.1.11+, this release should be the one. Hopefully there won't be v2.1.15 anytime in near future. (v2.2.rc1 does look close though.)
BTW. I know there are quite a lot of mails I haven't replied to in dovecot list. Too busy for now..
+ doveadm acl recalc command added
- v2.1.11+ had a race condition where it sometimes overwrote data in
dovecot.index.cache file. This could have caused Dovecot to return
the same cached data to two different messages.
- mdbox: Fixes to handling duplicate GUIDs during index rebuild
Lots of fixes since 2.2.alpha1, especially related to dsync. Also dsync
now supports syncing private message flags when INDEXPVT is used.
Here's again the list of all the major changes in v2.2:
* When creating home directories, the permissions are copied from the
parent directory if it has setgid-bit set. For full details, see
* "doveadm auth" command was renamed to "doveadm auth test"
* IMAP: ID command now advertises server name as Dovecot by default.
It was already trivial to guess this from command replies.
* dovecot.index.cache files can be safely accessed only by v2.1.11+.
Older versions may think they're corrupted and delete them.
+ Implemented IMAP MOVE and BINARY extensions
+ Implemented IMAP CATENATE, URLAUTH and URLAUTH=BINARY extensions
(by Stephan Bosch).
+ Implemented IMAP NOTIFY extension. Requires mailbox_list_index=yes
to be enabled.
+ Redesigned and rewritten dsync. The new design makes the syncing
faster, more reliable and more featureful. The new dsync protocol
isn't backwards compatible with old dsync versions (but is designed
to be forwards compatible with future versions).
+ All mailbox formats now support per-user message flags for shared
mailboxes by using a private index. It can be enabled by adding
:INDEXPVT=<path> to mail location. This should be used instead of
:INDEX also for Maildir/mbox to improve performance.
+ Improved mailbox list indexes. They should be usable now, although
still disabled by default.
+ Added LAYOUT=index. The mailbox directories are created using their
GUIDs in the filesystem, while the actual GUID <-> name mapping
exists only in the index.
+ LMTP proxy: Implemented XCLIENT extension for passing remote IP
address through proxy.