# CodeIgniter User Guide Version 2.1.2

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# Upgrading from 1.5.0 to 1.5.2

Note: The instructions on this page assume you are running version 1.5.0 or 1.5.1. If you have not upgraded to that version please do so first.

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:

- system/helpers/download_helper.php
- system/helpers/form_helper.php
- system/libraries/Table.php
- system/libraries/User_agent.php
- system/libraries/Exceptions.php
- system/libraries/Input.php
- system/libraries/Router.php
- system/libraries/Loader.php
- system/libraries/Image_lib.php
- system/language/english/unit_test_lang.php
- system/database/DB_active_rec.php
- system/database/drivers/mysqli/mysqli_driver.php
- codeigniter/

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.