# Upgrading from 2.1.4 to 2.2.x

注解

The 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 <http://php.net/manual/en/mcrypt.setup.php>.

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.

注解

If you have any custom developed files in these folders please make copies of them first.