Changes 2.2.10:
+ auth: passdb/userdb dict rewrite to support much more complex
  setups. See doc/example-config/dovecot-dict-auth.conf.ext.
  The old settings will continue to work.
+ auth: Added userdb result_success/failure/tempfail and skip
  settings, similar to passdb's. See
  http://wiki2.dovecot.org/UserDatabase
+ imap: Implemented SETQUOTA command for admin user when quota_set is
  configured. See http://master.wiki2.dovecot.org/Quota/Configuration
+ quota: Support "*" and "?" wildcards in mailbox names in quota_rules
+ mysql: Added ssl_verify_server_cert=no|yes parameter. This currently
  defaults to "no" to make sure nothing breaks, but likely will become
  "yes" in Dovecot v2.3.
+ ldap: Added blocking=yes setting to use auth worker processes for
  ldap lookups. This is a workaround for now to be able to use multiple
  simultaneous LDAP connections.
+ pop3c+dsync performance improvements
- quota-status: quota_grace was ignored
- ldap: Fixed memory leak with auth_bind=yes and without
  auth_bind_userdn.
- imap: Don't send HIGHESTMODSEQ anymore on SELECT/EXAMINE when
  CONDSTORE/QRESYNC has never before been enabled for the mailbox.
- imap: Fixes to handling mailboxes without permanent modseqs.
  (When [NOMODSEQ] is returned by SELECT, mainly with in-memory
  indexes.)
- imap: Various fixes to METADATA support.
- stats plugin: Processes that only temporarily dropped privileges
  (e.g. indexer-worker) may have been logging errors about not being
  able to open /proc/self/io.

(adam)