diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+5.0.1 [2018.03.07]
+------------------
+* Fix the build on old GHCs with `transformers-0.4`.
+
 5 [2018.01.28]
 --------------
 * Add a `Semigroup` instance for `IterT`.
diff --git a/examples/free-examples.cabal b/examples/free-examples.cabal
--- a/examples/free-examples.cabal
+++ b/examples/free-examples.cabal
@@ -45,7 +45,8 @@
     base == 4.*,
     free,
     HGL,
-    mtl  >= 2.0.1 && < 2.3
+    mtl          >= 2.0.1 && < 2.3,
+    transformers >= 0.2   && < 0.6
 
 executable free-newton-coiter
   hs-source-dirs: .
diff --git a/free.cabal b/free.cabal
--- a/free.cabal
+++ b/free.cabal
@@ -1,6 +1,6 @@
 name:          free
 category:      Control, Monads
-version:       5
+version:       5.0.1
 license:       BSD3
 cabal-version: >= 1.18
 license-file:  LICENSE
@@ -84,7 +84,7 @@
     transformers-base    < 0.5,
     transformers-compat  >= 0.3     && < 1,
     template-haskell     >= 2.7.0.0 && < 3,
-    exceptions           >= 0.6 && < 0.9,
+    exceptions           >= 0.6 && < 0.10,
     containers           < 0.6
 
   exposed-modules:
diff --git a/src/Control/Monad/Free/Ap.hs b/src/Control/Monad/Free/Ap.hs
--- a/src/Control/Monad/Free/Ap.hs
+++ b/src/Control/Monad/Free/Ap.hs
@@ -12,17 +12,17 @@
 -- |
 -- \"Applicative Effects in Free Monads\"
 --
--- Often times, the '(<*>)' operator can be more efficient than 'ap'.
+-- Often times, the '(\<*\>)' operator can be more efficient than 'ap'.
 -- Conventional free monads don't provide any means of modeling this.
 -- The free monad can be modified to make use of an underlying applicative.
--- But it does require some laws, or else the '(<*>)' = 'ap' law is broken.
+-- But it does require some laws, or else the '(\<*\>)' = 'ap' law is broken.
 -- When interpreting this free monad with 'foldFree',
 -- the natural transformation must be an applicative homomorphism.
 -- An applicative homomorphism @hm :: (Applicative f, Applicative g) => f x -> g x@
 -- will satisfy these laws.
 --
 -- * @hm (pure a) = pure a@
--- * @hm (f <*> a) = hm f <*> hm a@
+-- * @hm (f \<*\> a) = hm f \<*\> hm a@
 --
 -- This is based on the \"Applicative Effects in Free Monads\" series of articles by Will Fancher
 --
diff --git a/src/Control/Monad/Trans/Free/Church.hs b/src/Control/Monad/Trans/Free/Church.hs
--- a/src/Control/Monad/Trans/Free/Church.hs
+++ b/src/Control/Monad/Trans/Free/Church.hs
@@ -80,10 +80,18 @@
 instance (Functor f, Monad m, Ord1 f, Ord1 m) => Ord1 (FT f m) where
   liftCompare cmp x y= liftCompare cmp (fromFT x) (fromFT y)
 #else
-instance (Functor f, Monad m, Eq1 f, Eq1 m) => Eq1 (FT f m) where
+instance ( Functor f, Monad m, Eq1 f, Eq1 m
+# if !(MIN_VERSION_base(4,8,0))
+         , Functor m
+# endif
+         ) => Eq1 (FT f m) where
   eq1 x y = eq1 (fromFT x) (fromFT y)
 
-instance (Functor f, Monad m, Ord1 f, Ord1 m) => Ord1 (FT f m) where
+instance ( Functor f, Monad m, Ord1 f, Ord1 m
+# if !(MIN_VERSION_base(4,8,0))
+         , Functor m
+# endif
+         ) => Ord1 (FT f m) where
   compare1 x y = compare1 (fromFT x) (fromFT y)
 #endif