diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,11 @@
 # Revision history for greskell
 
+## 0.1.1.0  -- 2018-04-08
+
+* Add Semigroup instance to PropertyMapSingle and PropertyMapList.
+* Confirmed test with base-4.11 (with hint-test and server-test disabled)
+
+
 ## 0.1.0.0  -- 2018-03-12
 
 * First version. Released on an unsuspecting world.
diff --git a/greskell.cabal b/greskell.cabal
--- a/greskell.cabal
+++ b/greskell.cabal
@@ -1,5 +1,5 @@
 name:                   greskell
-version:                0.1.0.0
+version:                0.1.1.0
 author:                 Toshio Ito <debug.ito@gmail.com>
 maintainer:             Toshio Ito <debug.ito@gmail.com>
 license:                BSD3
@@ -32,7 +32,7 @@
                         Data.Greskell.Graph,
                         Data.Greskell.GTraversal
   -- other-modules:        
-  build-depends:        base >=4.9.0.0 && <4.11,
+  build-depends:        base >=4.9.0.0 && <4.12,
                         greskell-core >=0.1.0.0 && <0.2,
                         text >=1.2.2.1 && <1.3,
                         transformers >=0.5.2 && <0.6,
@@ -64,7 +64,7 @@
   ghc-options:          -Wall -fno-warn-unused-imports "-with-rtsopts=-M512m"
   main-is:              DocTest.hs
   build-depends:        base,
-                        doctest >=0.11 && <0.15,
+                        doctest >=0.11 && <0.16,
                         doctest-discover >=0.1.0.8 && <0.2
 
 
diff --git a/src/Data/Greskell/Graph.hs b/src/Data/Greskell/Graph.hs
--- a/src/Data/Greskell/Graph.hs
+++ b/src/Data/Greskell/Graph.hs
@@ -393,10 +393,12 @@
 newtype PropertyMapGeneric t p v = PropertyMapGeneric (HM.HashMap Text (t (p v)))
                                  deriving (Show,Eq)
 
+instance Semigroup (t (p v)) => Semigroup (PropertyMapGeneric t p v) where
+  (PropertyMapGeneric a) <> (PropertyMapGeneric b) = PropertyMapGeneric $ HM.unionWith (<>) a b
+
 instance Semigroup (t (p v)) => Monoid (PropertyMapGeneric t p v) where
   mempty = PropertyMapGeneric mempty
-  mappend (PropertyMapGeneric a) (PropertyMapGeneric b) =
-    PropertyMapGeneric $ HM.unionWith (<>) a b
+  mappend = (<>)
 
 instance (Functor t, Functor p) => Functor (PropertyMapGeneric t p) where
   fmap f (PropertyMapGeneric hm) = PropertyMapGeneric $ (fmap . fmap . fmap) f hm
@@ -442,7 +444,7 @@
 -- property maps share some same keys, the value from the left map
 -- wins.
 newtype PropertyMapSingle p v = PropertyMapSingle (PropertyMapGeneric Semigroup.First p v)
-                              deriving (Show,Eq,Monoid,Functor,Foldable,Traversable)
+                              deriving (Show,Eq,Semigroup,Monoid,Functor,Foldable,Traversable)
 
 instance PropertyMap PropertyMapSingle where
   lookupOne k (PropertyMapSingle (PropertyMapGeneric hm)) = fmap Semigroup.getFirst $ HM.lookup k hm
@@ -466,7 +468,7 @@
 -- property maps share some same keys, those property lists are
 -- concatenated.
 newtype PropertyMapList p v = PropertyMapList (PropertyMapGeneric NonEmpty p v)
-                            deriving (Show,Eq,Monoid,Functor,Foldable,Traversable)
+                            deriving (Show,Eq,Semigroup,Monoid,Functor,Foldable,Traversable)
 
 instance PropertyMap PropertyMapList where
   lookupList k (PropertyMapList (PropertyMapGeneric hm)) = maybe [] NL.toList $ HM.lookup k hm