diff --git a/process-extras.cabal b/process-extras.cabal
--- a/process-extras.cabal
+++ b/process-extras.cabal
@@ -1,5 +1,5 @@
 Name:               process-extras
-Version:            0.7.2
+Version:            0.7.3
 Synopsis:           Process extras
 Description:        Extends <http://hackage.haskell.org/package/process>.
                     Read process input and output as ByteStrings or
diff --git a/src/System/Process/Common.hs b/src/System/Process/Common.hs
--- a/src/System/Process/Common.hs
+++ b/src/System/Process/Common.hs
@@ -94,6 +94,11 @@
     mappend x (ExitFailure 0) = x
     mappend _ x = x
 
+#if MIN_VERSION_base(4,11,0)
+instance Semigroup ExitCode where
+  (<>) = mappend
+#endif
+
 -- | Process IO is based on the 'ListLikeIO' class from the ListLike
 -- package
 class ListLikeIO text char => ListLikeProcessIO text char where