All PHP-related elements in this book are based on the version 4 family, which has been in production for several years. During that time, the PHP Group and the developers at Zend Technologies have also been working on the next generation of PHP, version 5. Given how full-featured PHP has become since its inception, it's difficult to imagine what the next generation could possibly contain.
In this short chapter, you'll learn about the new features in PHP 5, including
An overview of the new object model
An overview of other new features
When to consider upgrading to PHP 5