login to your plesk control panel Click on PHP Selector, on the right hand side Near the top of the screen, you can select the PHP version that you want to use Below this, you can turn PHP modules on or off by checking the checkboxes. When you have selected the version of PHP you want, or the modules you want, click save. Back at the top of the screen, click PHP settings On this page, you can change settings such as the memory limit, the post max size and the upload max size settings. When you have applied your changes, hit save. You can return to the module settings page by clicking on general.