diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,8 @@
+4.1
+---
+* Added `Plated` instances for various free monad variants.
+* Compatibility with GHC HEAD (7.9+)
+
 4.0.7
 -----
 * Removed dependency on `constraints`. It was used in a pre-release version of 4.0 but never made it into 4.0, but the dependency had remained around complicating builds for GHC 7.4.
diff --git a/lens.cabal b/lens.cabal
--- a/lens.cabal
+++ b/lens.cabal
@@ -1,6 +1,6 @@
 name:          lens
 category:      Data, Lenses, Generics
-version:       4.0.7
+version:       4.1
 license:       BSD3
 cabal-version: >= 1.8
 license-file:  LICENSE
@@ -192,6 +192,7 @@
     containers                >= 0.4.0    && < 0.6,
     distributive              >= 0.3      && < 1,
     filepath                  >= 1.2.0.0  && < 1.4,
+    free                      >= 4        && < 5,
     ghc-prim,
     hashable                  >= 1.1.2.3  && < 1.3,
     exceptions                >= 0.1.1    && < 1,
diff --git a/src/Control/Lens/Internal/TupleIxedTH.hs b/src/Control/Lens/Internal/TupleIxedTH.hs
--- a/src/Control/Lens/Internal/TupleIxedTH.hs
+++ b/src/Control/Lens/Internal/TupleIxedTH.hs
@@ -63,7 +63,11 @@
 tupleIxed n = instanceD (cxt eqs) (conT ixedN `appT` fullTupleT n) [funD ixN clauses]
   where
   ty0:tyN = take n tupleVarTypes
+#if __GLASGOW_HASKELL__ >= 709
+  eqs     = [AppT . AppT EqualityT <$> ty0 <*> ty | ty <- tyN]
+#else
   eqs     = [ty0 `equalP` ty | ty <- tyN]
+#endif
   clauses = map nClause [0..n-1] ++ [otherClause]
 
   -- ix i f (a,..) = fmap (\x->(a,..x..)) (f z)
diff --git a/src/Control/Lens/Plated.hs b/src/Control/Lens/Plated.hs
--- a/src/Control/Lens/Plated.hs
+++ b/src/Control/Lens/Plated.hs
@@ -79,20 +79,27 @@
   )
   where
 
-import           Control.Applicative
-import           Control.Lens.Fold
-import           Control.Lens.Getter
-import           Control.Lens.Indexed
-import           Control.Lens.Internal.Context
-import           Control.Lens.Type
-import           Control.Lens.Setter
-import           Control.Lens.Traversal
+import Control.Applicative
+import Control.Comonad.Cofree
+import Control.Lens.Fold
+import Control.Lens.Getter
+import Control.Lens.Indexed
+import Control.Lens.Internal.Context
+import Control.Lens.Type
+import Control.Lens.Setter
+import Control.Lens.Traversal
+import Control.Monad.Free as Monad
+import Control.Monad.Free.Church as Church
+import Control.Monad.Trans.Free as Trans
+-- import Control.Monad.Trans.Free.Church as ChurchT
+import Control.MonadPlus.Free as MonadPlus
 import qualified Language.Haskell.TH as TH
-import           Data.Aeson
-import           Data.Data
-import           Data.Data.Lens
-import           Data.Monoid
-import           Data.Tree
+import Data.Aeson
+import Data.Bitraversable
+import Data.Data
+import Data.Data.Lens
+import Data.Monoid
+import Data.Tree
 
 #ifdef HLINT
 {-# ANN module "HLint: ignore Reduce duplication" #-}
@@ -201,6 +208,29 @@
 instance Plated [a] where
   plate f (x:xs) = (x:) <$> f xs
   plate _ [] = pure []
+
+instance Traversable f => Plated (Monad.Free f a) where
+  plate f (Monad.Free as) = Monad.Free <$> traverse f as
+  plate _ x         = pure x
+
+instance (Traversable f, Traversable m) => Plated (Trans.FreeT f m a) where
+  plate f (Trans.FreeT xs) = Trans.FreeT <$> traverse (bitraverse pure f) xs
+
+instance Traversable f => Plated (MonadPlus.Free f a) where
+  plate f (MonadPlus.Free as) = MonadPlus.Free <$> traverse f as
+  plate f (MonadPlus.Plus as) = MonadPlus.Plus <$> traverse f as
+  plate _ x         = pure x
+
+instance Traversable f => Plated (Church.F f a) where
+  plate f = fmap Church.toF . plate (fmap Church.fromF . f . Church.toF) . Church.fromF
+
+-- -- This one can't work
+--
+-- instance (Traversable f, Traversable m) => Plated (ChurchT.FT f m a) where
+--   plate f = fmap ChurchT.toFT . plate (fmap ChurchT.fromFT . f . ChurchT.toFT) . ChurchT.fromFT
+
+instance Traversable f => Plated (Cofree f a) where
+  plate f (a :< as) = (:<) a <$> traverse f as
 
 instance Plated (Tree a) where
   plate f (Node a as) = Node a <$> traverse f as
diff --git a/src/Control/Lens/TH.hs b/src/Control/Lens/TH.hs
--- a/src/Control/Lens/TH.hs
+++ b/src/Control/Lens/TH.hs
@@ -1030,7 +1030,11 @@
         ctx = dataContext dataDecl
         ps = filter relevantCtx (substTypeVars m ctx)
         qs = case maybeClassName of
+#if __GLASGOW_HASKELL__ >= 709
+           Just n | not (cfg^.createClass) -> AppT (ConT n) (VarT t) : (ctx ++ ps)
+#else
            Just n | not (cfg^.createClass) -> ClassP n [VarT t] : (ctx ++ ps)
+#endif
                   | otherwise              -> ps
            _                               -> ctx ++ ps
         tvs' = case maybeClassName of
@@ -1162,7 +1166,11 @@
        appliedType' = return (fullType dataDecl (map VarT typeArgs'))
 
        -- Con a' b' c'... ~ t
+#if __GLASGOW_HASKELL__ >= 709
+       eq = AppT. AppT EqualityT <$> appliedType' <*> t
+#else
        eq = equalP appliedType' t
+#endif
 
        -- Rewrapped (Con a b c...) t
        klass = conT ''Rewrapped `appsT` [appliedType, t]
diff --git a/src/Data/List/Lens.hs b/src/Data/List/Lens.hs
--- a/src/Data/List/Lens.hs
+++ b/src/Data/List/Lens.hs
@@ -49,7 +49,7 @@
 {-# INLINE prefixed #-}
 
 -- | A 'Prism' stripping a suffix from a list when used as a 'Traversal', or
--- prepending that prefix when run backwards:
+-- appending that suffix when run backwards:
 --
 -- >>> "review" ^? suffixed "view"
 -- Just "re"
diff --git a/src/Language/Haskell/TH/Lens.hs b/src/Language/Haskell/TH/Lens.hs
--- a/src/Language/Haskell/TH/Lens.hs
+++ b/src/Language/Haskell/TH/Lens.hs
@@ -249,9 +249,11 @@
   , _NumTyLit
   , _StrTyLit
 #endif
+#if __GLASGOW_HASKELL__ < 709
   -- ** Pred Prisms
   , _ClassP
   , _EqualP
+#endif
 #if MIN_VERSION_template_haskell(2,9,0)
   -- ** Role Prisms
   , _NominalR
@@ -322,9 +324,11 @@
        where s' = s `Set.union` setOf typeVars bs
   typeVarsEx _ _ t                   = pure t
 
+#if __GLASGOW_HASKELL__ < 709
 instance HasTypeVars Pred where
   typeVarsEx s f (ClassP n ts) = ClassP n <$> typeVarsEx s f ts
   typeVarsEx s f (EqualP l r)  = EqualP <$> typeVarsEx s f l <*> typeVarsEx s f r
+#endif
 
 instance HasTypeVars Con where
   typeVarsEx s f (NormalC n ts) = NormalC n <$> traverseOf (traverse . _2) (typeVarsEx s f) ts
@@ -361,9 +365,11 @@
 instance SubstType t => SubstType [t] where
   substType = map . substType
 
+#if __GLASGOW_HASKELL__ < 709
 instance SubstType Pred where
   substType m (ClassP n ts) = ClassP n (substType m ts)
   substType m (EqualP l r)  = substType m (EqualP l r)
+#endif
 
 -- | Provides a 'Traversal' of the types of each field of a constructor.
 conFields :: Traversal' Con StrictType
@@ -1753,6 +1759,7 @@
       reviewer x = Left x
 #endif
 
+#if __GLASGOW_HASKELL__ < 709
 _ClassP :: Prism' Pred (Name, [Type])
 _ClassP
   = prism remitter reviewer
@@ -1768,6 +1775,7 @@
       remitter (x, y) = EqualP x y
       reviewer (EqualP x y) = Right (x, y)
       reviewer x = Left x
+#endif
 
 #if MIN_VERSION_template_haskell(2,9,0)
 _NominalR :: Prism' Role ()