PHP is updated once again, as told in an announcement on PHP.net:

The PHP development team announces the immediate availability of PHP 5.4.6 and PHP 5.3.16. These releases fix over 20 bugs. All users of PHP are encouraged to upgrade to PHP 5.4.6, or at least 5.3.16.

From PHP: News Archive - 2012.

If you're still using an older version of PHP, like 5.2 or 4 (yikes!), you should really update to a newer release.  Some of the newer features are pretty fascinating, like the built-in web server in 5.4.