diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -1,3 +1,7 @@
+1.2.0.1
+-----
+* Fix build on GHC 7.0.4
+
 1.1.1
 -----
 * Added `Data.Functor.Contravariant.Applicative`
diff --git a/Data/Functor/Contravariant.hs b/Data/Functor/Contravariant.hs
--- a/Data/Functor/Contravariant.hs
+++ b/Data/Functor/Contravariant.hs
@@ -10,11 +10,17 @@
 #define MIN_VERSION_tagged(x,y,z) 1
 #endif
 
-#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702 && MIN_VERSION_transformers(0,3,0) && MIN_VERSION_tagged(0,6,1)
+#ifndef MIN_VERSION_base
+#define MIN_VERSION_base(x,y,z) 1
+#endif
+
+#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702
+#if MIN_VERSION_transformers(0,3,0) && MIN_VERSION_tagged(0,6,1)
 {-# LANGUAGE Safe #-}
 #else
 {-# LANGUAGE Trustworthy #-}
 #endif
+#endif
 
 -----------------------------------------------------------------------------
 -- |
@@ -247,6 +253,7 @@
   mempty = Op (const mempty)
   mappend (Op p) (Op q) = Op $ \a -> mappend (p a) (q a)
 
+#if MIN_VERSION_base(4,5,0)
 instance Num a => Num (Op a b) where
   Op f + Op g = Op $ \a -> f a + g a
   Op f * Op g = Op $ \a -> f a * g a
@@ -279,3 +286,4 @@
   acosh (Op f) = Op $ acosh . f
   Op f ** Op g = Op $ \a -> f a ** g a
   logBase (Op f) (Op g) = Op $ \a -> logBase (f a) (g a)
+#endif
diff --git a/Data/Functor/Contravariant/Compose.hs b/Data/Functor/Contravariant/Compose.hs
--- a/Data/Functor/Contravariant/Compose.hs
+++ b/Data/Functor/Contravariant/Compose.hs
@@ -39,6 +39,10 @@
   conquer = ComposeFC $ pure conquer
   divide abc (ComposeFC fb) (ComposeFC fc) = ComposeFC $ divide abc <$> fb <*> fc
 
+instance (Applicative f, Decidable g) => Decidable (ComposeFC f g) where
+  lose f = ComposeFC $ pure (lose f)
+  choose abc (ComposeFC fb) (ComposeFC fc) = ComposeFC $ choose abc <$> fb <*> fc
+
 -- | Composition of contravariant and covariant functors
 newtype ComposeCF f g a = ComposeCF { getComposeCF :: f (g a) }
 
@@ -54,5 +58,3 @@
 
 funzip :: Functor f => f (a, b) -> (f a, f b)
 funzip = fmap fst &&& fmap snd
-
--- | Composition of contravariant and covariant functors
diff --git a/contravariant.cabal b/contravariant.cabal
--- a/contravariant.cabal
+++ b/contravariant.cabal
@@ -1,6 +1,6 @@
 name:          contravariant
 category:      Control, Data
-version:       1.2
+version:       1.2.0.1
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE