- auth: Auth caching was done too aggressively when %variables were
used in default_fields, override_fields or LDAP pass/user_attrs.
userdb result_* were also ignored when user was found from cache.
- imap: Fixed various assert-crashes caused v2.2.20+. Some of them
caught actual hangs or otherwise unwanted behavior towards IMAP
clients.
- Expunges were forgotten in some situations, for example when
pipelining multiple IMAP MOVE commands.
- quota: Per-namespaces quota were broken for dict and count backends
in v2.2.20+
- fts-solr: Search queries were using OR instead of AND as the
separator for multi-token search queries in v2.2.20+.
- Single instance storage support wasn't really working in v2.2.16+
- dbox: POP3 message ordering wasn't working correctly.
- virtual plugin: Fixed crashes related to backend mailbox deletions.
