Posted By Roman U. on 11/15/2023 9:56 AM
afaik, the difference between the install and the upgrade package is that there is no web(dot)config file in the latter. Everything else is the same.
Even true pros make mistakes sometimes, but it's good to have someone you can trust... ;-)
Maybe they forgot to unblock one of the upgrade packages ZIP file before extracting. I would try to go back to the start, upgrade the first step, try if it works, then upgrade the second step and so on.