IN THIS APPENDIX
PHP 4 versus PHP 5: understanding core differences
WordPress and PHP 5
The issue of PHP version requirements in WordPress has been a point of contention in the WordPress community. The minimum PHP requirement for WordPress is currently 4.3.0, but the PHP 4 branch has already reached the end of its life, meaning it will not receive any more security updates and is not being officially maintained anymore.
In addition, PHP 5 is much more object oriented, bringing it into its own in comparison with other object-oriented languages in use. The drive to PHP 5 in WordPress has been a long battle as developers have advocated for the new tools and features available, while core developers have maintained a PHP 4 loyalty for the sake of compatibility with the majority of Web hosts. This debate is examined in this appendix.
On August 8, 2008, PHP 4 hit the end of its life, and developers began using the event as a reason to argue that PHP 5 should be a WordPress minimum requirement. The leadership in the WordPress development community refused to adopt PHP 5 requirements, however, wanting instead to ensure that WordPress would continue to work on the most number of systems. It is expected that PHP 4 support will be going away soon. As of this writing, only 12.5% of WordPress blogs are running on PHP 4.
To understand this debate in the community, it's necessary to understand the enhancements made in PHP ...