PHP 5.3.0 looks promising. So far:
- __callStatic()
- Circular reference garbage collection
- get_called_class()
- Closures
- DateTime::getTimestamp()
- Namespaces
- Late Static Binding
- Phar as part of the default install
- __DIR__ — no more
dirname(__FILE__)!
PHP 5.3.0 was released on 23 June, 2009! A migration guide is available.