-Upgrade your zen cart store to the latest version
-Upgrade Zen Cart store on your server in a separate folder e.g /dev155 and will make sure everything works fine after the upgrade.
-Once you will verify that everything is working fine, will then move the upgraded zen cart from /dev155 to root.
-Install all the modules that you had on your old Zen Cart Installation (Provided their recent/upgraded versions are available)
Before you buy:
-Share a link of your Zen Cart Ecommerce Website with me