PHP 5.3 upgrading notes

This document has been removed in favor of UPGRADING and will eventually live in the PHP Manual (see below)
The 5.3.0 upgrade guide can be seen here: http://docs.php.net/migration53
The 5.2.0 upgrade guide can be seen here: http://docs.php.net/migration52
The 5.1.0 upgrade guide can be seen here: http://docs.php.net/migration51