In a new post today Mark van der Velden looks at how to run more than one PHP version on one web server.

This is a blog about running two PHP versions on one webserver and using multiple php.ini files, this combination can be a tricky one to tackle. But luckily one we can tackle quite easily as long as one of the PHP versions is >= 5.2.7. For this example I'll be using Apache, but the webserver flavor doesn't really matter. The most important part is the "PHP_INI_SCAN_DIR" environment variable.

He wanted to be able to run a specific version (or versions) on the web server for applications that depended on or required a certain PHP version - like one that was written in PHP4 that would have all sorts of quirks if moved to PHP5. You'll need to know a bit about installing packages and how to compile one of the versions yourself, but configuring the Apache httpd.conf is simple. Virtual hosts make it easy to define a specific version for different parts of the site.