Courtesy of PHP Announcements:

The PHP development team announces the immediate availability of PHP 5.4.11 and PHP 5.3.21.
These releases fix about 10 bugs. All users of PHP are encouraged to upgrade to PHP 5.4.
PHP 5.3.20 is recommended for those wishing to remain on the 5.3 series.

The full list of changes are recorded in the ChangeLog on http://www.php.net/ChangeLog-5.php

For source downloads of PHP 5.4.11 and PHP 5.3.21 please visit the downloads page at http://www.php.net/downloads.php.

Windows binaries can be found on http://windows.php.net/download/

Russ McRee | @holisticinfosec