diff --git a/Data/MessagePack/Pack.hs b/Data/MessagePack/Pack.hs
--- a/Data/MessagePack/Pack.hs
+++ b/Data/MessagePack/Pack.hs
@@ -34,8 +34,8 @@
 import qualified Data.Text.Lazy as TL
 import qualified Data.Text.Lazy.Encoding as TL
 import qualified Data.Vector as V
-import Foreign hiding (unsafeLocalState)
-import Foreign.Marshal.Unsafe
+import Foreign
+import qualified System.IO.Unsafe as SIU
 
 import Data.MessagePack.Assoc
 import Data.MessagePack.Internal.Utf8
@@ -100,7 +100,7 @@
     fromWord64be (cast d)
 
 cast :: (Storable a, Storable b) => a -> b
-cast v = unsafeLocalState $ with v $ peek . castPtr
+cast v = SIU.unsafePerformIO $ with v $ peek . castPtr
 
 instance Packable String where
   from = fromString encodeUtf8 B.length fromByteString
diff --git a/Data/MessagePack/Unpack.hs b/Data/MessagePack/Unpack.hs
--- a/Data/MessagePack/Unpack.hs
+++ b/Data/MessagePack/Unpack.hs
@@ -47,6 +47,7 @@
 import qualified Data.Vector as V
 import Data.Word
 import Foreign
+import qualified System.IO.Unsafe as SIU
 import Text.Printf
 
 import Data.MessagePack.Assoc
@@ -146,8 +147,7 @@
     case c of
       0xCA -> do
         bs <- A.take 4
-        -- TODO: unsafePerformIO => unsafeLocalState
-        return $! unsafePerformIO $ B.useAsCString (B.reverse bs) $ peek . castPtr
+        return $! SIU.unsafePerformIO $ B.useAsCString (B.reverse bs) $ peek . castPtr
       _ ->
         fail $ printf "invlid float tag: 0x%02X" c
 
@@ -157,7 +157,7 @@
     case c of
       0xCB -> do
         bs <- A.take 8
-        return $! unsafePerformIO $ B.useAsCString (B.reverse bs) $ peek . castPtr
+        return $! SIU.unsafePerformIO $ B.useAsCString (B.reverse bs) $ peek . castPtr
       _ ->
         fail $ printf "invlid double tag: 0x%02X" c
 
diff --git a/msgpack.cabal b/msgpack.cabal
--- a/msgpack.cabal
+++ b/msgpack.cabal
@@ -1,5 +1,5 @@
 Name:               msgpack
-Version:            0.7.1
+Version:            0.7.1.1
 Synopsis:           A Haskell implementation of MessagePack
 Description:        A Haskell implementation of MessagePack <http://msgpack.org/>
 Homepage:           http://msgpack.org/