You can select which version of PHP and which php modules you wish to run in your account. This is great for developers testing new versions functions or to test your current scripts on new php versions.
1- Login in your cPanel
2- Go to the "Software" section in the panel and click in the "Select PHP Version" icon/link.
3- Then select the php version you wish to run in your account.
4- Then click in the "Set as current" link to save your PHP settings.
5- You can modify some of the PHP variables using the "Switch to PHP options" button. This let you modify many of the php.ini variables for your account. Simply click in the variable current status and you will be able to modify it.