Some of the key features of PHP 5 include:
* PHP 5 features the Zend Engine 2.
* XML support has been completely redone in PHP 5, all extensions are now focused around the excellent libxml2 library (http://www.xmlsoft.org/).
* SQLite has been bundled with PHP. For more information on SQLite, please visit their website.
* A new SimpleXML extension for easily accessing and manipulating XML as PHP objects. It can also interface with the DOM extension and vice-versa.
* Streams have been greatly improved, including the ability to access low-level socket operations on streams.