diff --git a/pipes-transduce.cabal b/pipes-transduce.cabal
--- a/pipes-transduce.cabal
+++ b/pipes-transduce.cabal
@@ -1,5 +1,5 @@
 Name: pipes-transduce
-Version: 0.4.3.1
+Version: 0.4.3.2
 Cabal-Version: >=1.8.0.2
 Build-Type: Simple
 License: BSD3
diff --git a/src/Pipes/Transduce/Internal.hs b/src/Pipes/Transduce/Internal.hs
--- a/src/Pipes/Transduce/Internal.hs
+++ b/src/Pipes/Transduce/Internal.hs
@@ -102,8 +102,12 @@
 
 instance (S.Semigroup a) => S.Semigroup (Fold1 b e a) where
      s1 <> s2 = (S.<>) <$> s1 <*> s2
-    
+
+#if !(MIN_VERSION_base(4,11,0))
+instance (Monoid a,S.Semigroup a) => Monoid (Fold1 b e a) where
+#else
 instance (Monoid a) => Monoid (Fold1 b e a) where
+#endif
    mempty = pure mempty
 #if !(MIN_VERSION_base(4,11,0))
    mappend = (S.<>)
@@ -507,7 +511,11 @@
 instance (S.Semigroup a) => S.Semigroup (Fold2 b1 b2 e a) where
      s1 <> s2 = (S.<>) <$> s1 <*> s2
 
+#if !(MIN_VERSION_base(4,11,0))
+instance (Monoid a,S.Semigroup a) => Monoid (Fold2 b1 b2 e a) where
+#else
 instance (Monoid a) => Monoid (Fold2 b1 b2 e a) where
+#endif
    mempty = pure mempty
 #if !(MIN_VERSION_base(4,11,0))
    mappend = (S.<>)