As noted on the main PHp page today, the latest releases in both the 5.2.x series and the 4.4.x series of PHP have been released today - 5.2.2 and 4.4.7.
The PHP development team would like to announce the immediate availability of PHP 5.2.2 and availability of PHP 4.4.7. These releases are major stability and security enhancements of the 5.x and 4.4.x branches, and all users are strongly encouraged to upgrade to it as soon as possible. Further details about the PHP 5.2.2 release can be found in the release announcement for 5.2.2, the full list of changes is available in the ChangeLog for PHP 5. Details about the PHP 4.4.7 release can be found in the release announcement for 4.4.7, the full list of changes is available in the ChangeLog for PHP 4.
Among the updates in these new versions many security enhancements and fixes were made based off of several bug reports from Stanislav Malyshev, Stefan Esser and Ilia Alshanetsky (among others). Updates based on Stefan's comments were largely issues found during the Month of PHP Bugs.