Log Message:
Changes 2.2.11:
+ acl plugin: Added an alternative global ACL file that can contain
  mailbox patterns. See http://wiki2.dovecot.org/ACL for details.
+ imap proxy: Added proxy_nopipelining passdb setting to work around
  other IMAP servers' bugs (MS Exchange 2013 especially).
+ Added %{auth_user}, %{auth_username} and %{auth_domain} variables.
  See http://wiki2.dovecot.org/Variables for details.
+ Added support for LZ4 compression.
+ stats: Track also wall clock time for commands.
+ pop3_migration plugin improvements to try harder to match the UIDLs
  correctly.
- imap: SEARCH/SORT PARTIAL reponses may have been too large.
- doveadm backup: Fixed assert-crash when syncing mailbox deletion.