The PHP development team is proud to announce the first beta release of PHP 5.4. PHP 5.4 includes new language features and removes several legacy (deprecated) behaviors. Windows binaries can be downloaded from the Windows QA site.
Features added in this beta include several bug fixes, the addition of a callable typehint, a switch to timezone guessing (UTC is assumed if not set) and the mysql/mysqli/pdo_mysql extensions now use mysqlnd by default. There's a lot of smaller changes too - check out the latest NEWS file for the complete list.