Forgive me if I'm stating the obvious here, but the status of libraries like primitive, unordered-containers, and haskell-src-exts don't really have anything to do with GHC, since they're independent libraries that aren't shipped with GHC in any way.
If you're impatient to use the Haskell library ecosystem with GHC 8.4.1, I highly encourage you to use a solution like head.hackage [1], as many library authors are not as much of early adopters as we are :)