+ - Add src/configtest.php script which checks for common errors in the config.
+ - Improve display of some unparsable/absent dates (#891354).
+ - Add comment (Highest,Normal,Lowest) to X-Priority header.
+ Some SpamAssassin rule triggers on the absence of such a comment.
+ - Corrected moving of last message in a folder using Delete-Move-Next
+ functionality added to core in 1.5.0.
+ - Fix test for LOGINDISABLED, should only test when the auth_mech actually
+ is 'login'.
+ - Update required PHP version to 4.1.0, and remove PHP 4.0.x legacy code.