The first step is to backup your database just incase anything goes wrong with the upgrade process. We recommend the use of PHPMyAdmin for this task. You can download it from the website: http://ww.phpmyadmin.net.
The file whatsnew.txt list all of the files that have been updated but it is recommended that you upload all of the files from the archive. However, you should never overwrite your config.php file.
Upload the appropriate upgrade file to your server. It should be in the same folder as your config.php file. The file upgrade/index.html will tell you exactly which file to use. It is important that you use the correct upgrade file. Navigate your Web browser to this file and follow the instructions.
You should now upload all of the files in the upload folder, with the exception of config.php. If you have made changes to the templates or language files you should not overwrite these folders. However, you should note that there may be additional templates or language files in the latest release. This will be detailed in the whatsnew.txt file.
Now log on to the administration centre to ensure the upgrade process went smoothly. You should also send a WebCard to ensure your templates and languages are working as they should.
The last step is very important. You should remove the upgrade file that you uploaded. If you leave it on your server, your installation is at risk.