I haven't upgraded cPanel/WHM in two years. I currently have version 64.0 but it says that version 84.0.16 is available for upgrade. Since I've never upgraded cPanel (and this would appear to be a major upgrade), I'm concerned if it will affect any functionality in my OpenCart site. Should I be concerned? Are there any precautions I can take before doing the upgrade? If there are problems after upgrading, is it possible to revert back to a working version of the site?