To update your shop to the latest version please do the below steps:
- make a backup of all files in your current version
- make a dump of your current database
- download a new version from http://www.viart.com/php_shopping_cart_free_evaluation_download.html
- unzip the archive with the new version and replace your old files with the new ones (except the ones you've modified, e.g. templates, styles, images)
- copy the var_definition file from your backup 'includes' folder and paste it in the 'includes' folder of your new version
- go to your Administration panel (Tools> System Upgrade) and click the Upgrade Database button
- your shop is now updated to the latest version.
You can find more information in our online manual: http://www.viart.com/upgrade_step_by_step.html