diff --git a/msgpack-arbitrary.cabal b/msgpack-arbitrary.cabal
--- a/msgpack-arbitrary.cabal
+++ b/msgpack-arbitrary.cabal
@@ -1,5 +1,5 @@
 name:                 msgpack-arbitrary
-version:              0.1.2
+version:              0.1.3
 synopsis:             A Haskell implementation of MessagePack.
 homepage:             http://msgpack.org/
 license:              BSD3
@@ -38,7 +38,7 @@
       base                      < 5
     , QuickCheck
     , bytestring
-    , msgpack-types             >= 0.3 && < 0.4
+    , msgpack-types             >= 0.3.2 && < 0.4
     , quickcheck-instances
     , text
     , time
diff --git a/src/Test/QuickCheck/Instances/MessagePack.hs b/src/Test/QuickCheck/Instances/MessagePack.hs
--- a/src/Test/QuickCheck/Instances/MessagePack.hs
+++ b/src/Test/QuickCheck/Instances/MessagePack.hs
@@ -4,7 +4,7 @@
 module Test.QuickCheck.Instances.MessagePack () where
 
 import qualified Data.ByteString                      as S
-import           Data.MessagePack.Types               (Object (..))
+import           Data.MessagePack.Types               (Assoc (..), Object (..))
 import qualified Data.Text                            as T
 import           Test.QuickCheck.Arbitrary            (Arbitrary, arbitrary)
 import qualified Test.QuickCheck.Gen                  as Gen
@@ -27,3 +27,7 @@
         , ObjectExt    <$> arbitrary <*> arbitrary
         ]
         where negatives = Gen.choose (minBound, -1)
+
+
+instance Arbitrary a => Arbitrary (Assoc a) where
+    arbitrary = Assoc <$> arbitrary