diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,3 +1,4 @@
+Copyright (c) 2017-2018, The TokTok Team
 Copyright (c) 2009-2010, Hideyuki Tanaka
 All rights reserved.
 
diff --git a/data-msgpack.cabal b/data-msgpack.cabal
--- a/data-msgpack.cabal
+++ b/data-msgpack.cabal
@@ -1,5 +1,5 @@
 name:                 data-msgpack
-version:              0.0.12
+version:              0.0.13
 synopsis:             A Haskell implementation of MessagePack
 homepage:             http://msgpack.org/
 license:              BSD3
diff --git a/src/Data/MessagePack.hs b/src/Data/MessagePack.hs
--- a/src/Data/MessagePack.hs
+++ b/src/Data/MessagePack.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP  #-}
 {-# LANGUAGE Safe #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 --------------------------------------------------------------------
@@ -40,7 +41,11 @@
 
 -- | Unpack MessagePack binary to a Haskell value. If it fails, it fails in the
 -- Monad. In the Maybe monad, failure returns Nothing.
+#if (MIN_VERSION_base(4,13,0))
+unpack :: (Applicative m, Monad m, MonadFail m, MessagePack a)
+#else
 unpack :: (Applicative m, Monad m, MessagePack a)
+#endif
        => L.ByteString -> m a
 unpack = eitherToM . decodeOrFail >=> fromObject
   where