diff --git a/src/Database/PostgreSQL/Protocol/Store/Encode.hs b/src/Database/PostgreSQL/Protocol/Store/Encode.hs
index c5fd321..e3b2572 100644
--- a/src/Database/PostgreSQL/Protocol/Store/Encode.hs
+++ b/src/Database/PostgreSQL/Protocol/Store/Encode.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 module Database.PostgreSQL.Protocol.Store.Encode 
     ( Encode
     , getEncodeLen
@@ -26,15 +27,21 @@ import Data.ByteString.Internal (toForeignPtr)
 import Data.Store.Core          (Poke(..), unsafeEncodeWith, pokeStatePtr,
                                  pokeFromForeignPtr)
 
+import qualified Data.Semigroup as Sem
+
 data Encode = Encode {-# UNPACK #-} !Int !(Poke ())
 
-instance Semigroup Encode where
+instance Sem.Semigroup Encode where
   {-# INLINE (<>) #-}
   (Encode len1 f1) <> (Encode len2 f2) = Encode (len1 + len2) (f1 *> f2)
 
 instance Monoid Encode where
     {-# INLINE mempty #-}
     mempty = Encode 0 . Poke $ \_ offset -> pure (offset, ())
+#if !(MIN_VERSION_base(4,11,0))
+    mappend = (Sem.<>)
+#endif
+
 
 instance Show Encode where
     show (Encode len _) = "Encode instance of length " ++ show len
diff --git a/stack-ghc8.2.2.yaml b/stack-ghc8.2.2.yaml
new file mode 100644
index 0000000..9cd2430
--- /dev/null
+++ b/stack-ghc8.2.2.yaml
@@ -0,0 +1,22 @@
+# This file was automatically generated by 'stack init'
+#
+resolver: lts-11.22
+
+packages:
+- '.'
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+extra-deps: 
+    - socket-0.8.2.0
+    - socket-unix-0.2.0.0
+# <<<<<<< HEAD
+# =======
+#     - store-core-0.3
+#     - QuickCheck-2.9.2
+# >>>>>>> QuickCheck tests for existing codecs
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []
diff --git a/stack-ghc8.4.4.yaml b/stack-ghc8.4.4.yaml
new file mode 100644
index 0000000..02aa3cd
--- /dev/null
+++ b/stack-ghc8.4.4.yaml
@@ -0,0 +1,22 @@
+# This file was automatically generated by 'stack init'
+#
+resolver: lts-12.26
+
+packages:
+- '.'
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+extra-deps: 
+    - socket-0.8.2.0
+    - socket-unix-0.2.0.0
+# <<<<<<< HEAD
+# =======
+#     - store-core-0.3
+#     - QuickCheck-2.9.2
+# >>>>>>> QuickCheck tests for existing codecs
+
+# Override default flag values for local packages and extra-deps
+flags: {}
+
+# Extra package databases containing global packages
+extra-package-dbs: []