diff --git a/src/Data/Generics/Twins.hs b/src/Data/Generics/Twins.hs
--- a/src/Data/Generics/Twins.hs
+++ b/src/Data/Generics/Twins.hs
@@ -54,7 +54,7 @@
 
 #if __GLASGOW_HASKELL__ < 709
 import Control.Applicative (Applicative(..))
-import Data.Monoid         ( (<>), mconcat )
+import Data.Monoid         ( mappend, mconcat )
 #endif
 
 ------------------------------------------------------------------------------
@@ -284,7 +284,7 @@
         in
         case (repX, repY) of
           (AlgConstr nX,   AlgConstr nY)   ->
-            nX `compare` nY <> mconcat (gzipWithQ gcompare' x y)
+            nX `compare` nY `mappend` mconcat (gzipWithQ gcompare' x y)
           (IntConstr iX,   IntConstr iY)   -> iX `compare` iY
           (FloatConstr rX, FloatConstr rY) -> rX `compare` rY
           (CharConstr cX,  CharConstr cY)  -> cX `compare` cY
diff --git a/syb.cabal b/syb.cabal
--- a/syb.cabal
+++ b/syb.cabal
@@ -1,5 +1,5 @@
 name:                 syb
-version:              0.5
+version:              0.5.1
 license:              BSD3
 license-file:         LICENSE
 author:               Ralf Lammel, Simon Peyton Jones, Jose Pedro Magalhaes