[ninjaoxygen]

Yes, you're right, the last sentence is definitely a mistake on my part, I should have written less! Thanks for the links, paulirwin's sibling response is helpful too.

We had code using WCF and AppDomains that were always out of scope for .NET Core. WCF has a Core replacement now that is not quite one-for-one but AppDomains will never be supported in .NET Core / .NET 5.0+ and would indeed have to stay on 4.8 / 4.8.1 if they were still running.