As we can see, upgrading OpenCart is not a difficult task thanks to new upgrade script, but the upgrade process still needs a careful execution order. The most important thing is to back up files and the database beforehand. Also, we should be careful about not to overwrite working
config.php files with the empty config files that come with new versions.
In this chapter, we learned how to upgrade OpenCart on a web server and restore the old system if an upgrade fails.