The PHP development team is proud to announce the immediate availability of PHP 5.4.0. This release is a major leap forward in the 5.x series, and includes a large number of new features and bug fixes.

The key features of PHP 5.4.0 include:

New language syntax including Traits, shortened array syntax and more
Improved performance and reduced memory consumption
Support for multibyte languages now available in all builds of PHP at the flip of a runtime switch
Built-in webserver in CLI mode to simplify development workflows and testing
Cleaner code base thanks to the removal of multiple deprecated language features
Many more improvements and fixes
Changes that affect compatibility:

Register globals, magic quotes and safe mode were removed
The break/continue $var syntax was removed
The ini option allow_call_time_pass_reference was removed
The PHP default_charset is now "UTF-8"
Extensions moved to PECL:

ext/sqlite (ext/sqlite3 and ext/pdo_sqlite are not affected)
PHP 5.4 will be the last series to support Windows XP and Windows 2003. We will not provide binary packages for these Windows versions after PHP 5.4.

For users upgrading from PHP 5.3 there is a migration guide available here, detailing the changes between PHP 5.3 and PHP 5.4.0.

For a full list of changes in PHP 5.4.0, see the ChangeLog.