https://bugzilla.redhat.com/show_bug.cgi?id=1086273
--- Comment #4 from Jens Petersen petersen@redhat.com --- ghc-7.8.2 was released in April but it is somewhat buggy. ghc-7.8.3 release was expected early June but it is still slipping but I think it will come out soon.
Of course problem is after branching it will be quite a bit more work to backport ghc-7.8 to F21, but I think it should possible to finish that well before the Beta freeze.
I also plan to do a copr SCL for ghc783 for earlier releases.