Yesterday saw the release of the two latest versions of PHP in both the 5.2.x and 5.3.x series - 5.2.15 and 5.3.4. Here's a bit from each release announcement.

For 5.2.15:

The PHP development team would like to announce the immediate availability of PHP 5.2.15. This release marks the end of support for PHP 5.2. All users of PHP 5.2 are encouraged to upgrade to PHP 5.3. This release focuses on improving the security and stability of the PHP 5.2.x branch with a small number, of predominately security fixes.

For 5.3.4:

The PHP development team is proud to announce the immediate release of PHP 5.3.4. This is a maintenance release in the 5.3 series, which includes a large number of bug fixes.

For full details you can the the Changelogs for each release - 5.3.4 and 5.2.15. As always, you can download these latest versions from the main PHP site or your favorite local mirror.