############################# Upgrading from 2.1.4 to 2.2.x ############################# .. note:: The :doc:`Encrypt Class ` now requires the Mcrypt extension. If you were previously using the Encrypt Class without Mcrypt, then this is a breaking change. You must install the Mcrypt extension in order to upgrade. For information on installing Mcrypt please see the PHP `documentation `. Before performing an update you should take your site offline by replacing the index.php file with a static one. Step 1: Update your CodeIgniter files ===================================== Replace all files and directories in your "system" folder. .. note:: If you have any custom developed files in these folders please make copies of them first.