PHP Compatibility and Hosting Quick-Install Applications
PHP is a popular and simple server scripting language that enables Web developers to embed dynamic content into Web pages. PHP 4 and 5 are enabled for all Linux hosting accounts. PHP 5 is enabled for Windows hosting accounts running IIS 7, only.
If you have a Windows hosting account and the value application you want to install requires PHP 4, you can either purchase a new Linux hosting account or migrate your existing account from Windows to Linux.
For information on migrating an existing hosting account, see Switching your hosting account operating system.