Board Thread:General Discussion/@comment-28883325-20201008151255/@comment-9605025-20201010223634

The Unified Community Platform is referring to the concept of having all wikis use the same version of the same software with (as much as possible) the same features available. There has been no change to how the user database works. It was one database before UCP and it is one database for UCP as well. Global blocks have been a thing for years.

Another point of clarification, Recent Changes is not new. It is even older than the legacy platform. The only reason people think it is new is because Fandom made their custom extension, Wiki Activity, more accessible than Recent Changes on the legacy platform; so that is what people saw most of the time. As such, the "replacement" of Wiki Activity is nothing different from the other features you mentioned; discontinued support.