The links below will help with that. :)

https://hotcakescommerce....n-Upgrading-Hotcakes

https://hotcakescommerce....doesn-t-work-anymore

Merging viewset updates is also mentioned in every release notes in every release. :)

Thanks. But on the local server, after the upgrade, everything works. Should I also have problems with views there?

If issues are different from location to location, then this seems to be either a configuration issue and/or missing Windows and .NET updates. I'd suggest looking at those two things as possible causes of these issues. Compare IIS and permissions, then update all of the software on the server.