Hi, I have a umbrao 9.4.1 project, that has been updated to 10.5.1.

I did the upgrade, and pushed to to our test-server, which is a windows 10 machine running the project in IIS.

It was then pushed to the production server, which is the same setup.

But now, in production, whenever anyone tries to save or publish anything, I get this error:

One or more errors occurred. (Method not found: 'Umbraco.Cms.Core.Models.ContentScheduleCollection Umbraco.Cms.Core.Models.IContent.get_ContentSchedule()'.)

and when I look in the log, inside umbraco backoffice, it looks like the item actually has been published:

Document "title of content" (id=1625) cultures: "da" have been published.

But it has'nt, no changes have been made. Nothing has happened.

I then tried taking the entire production package, and cloning it on my test server, here it runs fine.

Can someone hint to me, or have a good idea what to look into?

Why would it all of a sudden not be able to find methods inside the umbraco DLL's on one server, but not on another?