PHP 5.1.0 Released

The PHP development team is proud to announce the release of PHP 5.1.0. Some of the key features of PHP 5.1.0 include:

* A complete rewrite of date handling code, with improved timezone support.
* Significant performance improvements compared to PHP 5.0.X.
* PDO extension is now enabled by default.
* Over 30 new functions in various extensions and built-in functionality.
* Bundled libraries, PCRE and SQLite upgraded to latest versions.
* Over 400 various bug fixes.
* PEAR upgraded to version 1.4.5

Announcement here.
Changelog here.
Upgrading guide here.