+ - Always ensure that the Reply-To header is a full email address in
+ outgoing messages
+ - Unified address book searches somewhat: file-backed address books now
+ search in each field individually; database-backed address books now
+ search in fields other than first/last name (nickname, email)
+ - Made performance improvements in security token handling
+ - Improvements for PHP 5.4 compatibility.
+ - Added option that allows users to have replies to their own
+ messages sent to the recipient of the previous message (#3520988).