Difference between PHP 4 and 5-New Extensions

PHP5 also introduces new default extensions.

1. SimpleXML for easy processing of XML data
2. DOM and XSL extensions are available for a much improved XML-consuming experience. A breath of fresh air after using DOMXML for PHP4!
3. PDO for working with databases. An excellent OO interface for interacting with your database.
4. Hash gives you access to a ton of hash functions if you need more then the usual md5 or sha1.