Oscommerce is a matured product and there is less frequent upgrades needed, below explain the process of upgrading from version ms1 to ms2, there are several steps involve in the process :-
NOTE: be sure to make a backup of your oscommerce folder and database before doing anything.
- download new oscommerce package, extract and FTP upload to a new folder in your hosting account
- change file permission for catalog/includes/configure.php to 0777 (CHMOD 0777)
- copy database of existing oscommerce database to a new database
- copy extra/pr21_to_pr22/ms1_to_ms2.php in new oscommerce program folder to oscommerce root folder, this is the upgrade script that will update the database
- enter the URL in browser (http://youroscommercepath/ms1_to_ms2.php), enter the new database name and database login info, hit enter and this script will perform upgrade to the database
- test the new installation on your browser to make sure everything is working properly
- when everything is working as expected, rename the live oscommerce folder to a backup folder name, and then rename the upgraded and tested oscommerce folder to your live oscommerce folder name
- your oscommerce upgrade is done
