Upgrading from 1.5.2 to 1.5.3
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 these files and directories in your "system" folder with the new versions:
Note: If you have any custom developed files in these folders please make copies of them first.
Step 2: Update your user guide
Please also replace your local copy of the user guide with the new version.