When we released FP Haskell Center 3.1, we deprecated our support for GHC 7.4. Till now, we've left that support in place to give users a grace window for upgrading to GHC 7.8. I'm announcing our plans to fully remove GHC 7.4 support in a near release, most likely FP Haskell Center 3.3.
One of the main reasons we are removing support is that the library versions compatible with GHC 7.4 are no longer being maintained.
If you are still actively using GHC 7.4 on FP Haskell Center, and would like us to consider extending its lifetime, please let us know (via the feedback link at the top of this page) in the next few weeks.