Thought I would bring to everyone's attention that php 5.3 is currently scheduled for end of life on March 2013 (3 months from now). php 5.3 was originally released June 2009.
http://php.net/archive/2012.php#id2012-12-20-1
php 5.5 is generally "planned" in or around that time which would technically make 5.4 legacy (1 build behind current).
http://php.net/archive/2012.php#id2012-12-20-1
Please note that the PHP 5.3 series will enter an end of life cycle and receive only critical fixes as of March 2013.