The PHP development team is proud to announce the second release candidate of PHP 5.2.10 (PHP 5.2.10RC2) and the third release candidate of PHP 5.3.0 (PHP 5.3.0RC3). These RCs focuses on bug fixes and stability improvements, and we hope only minimal changes are required for the next candidate or final stable releases. PHP 5.2.10 is a pure maintenance release for providing bugfixes and stability updates. PHP 5.3.0 is a newly developed version of PHP featuring long-awaited features like namespaces, late static binding, closures and much more. Please download and test these release candidates, and report any issues found. Downloads and further information is available at qa.php.net. See also the work in progress 5.3 upgrade guide.

Source: http://www.php.net/index.php#id2009-06-12-1