diff --git a/Data/Packer/Internal.hs b/Data/Packer/Internal.hs
--- a/Data/Packer/Internal.hs
+++ b/Data/Packer/Internal.hs
@@ -42,7 +42,7 @@
 import Data.Data
 import Data.Word
 import Control.Exception (Exception, throwIO, try, SomeException)
-import Control.Monad.Trans
+import Control.Monad.IO.Class
 import Control.Applicative (Alternative(..), Applicative(..), (<$>), (<*>))
 import Control.Concurrent.MVar
 import Control.Monad (when)
diff --git a/Data/Packer/Unsafe.hs b/Data/Packer/Unsafe.hs
--- a/Data/Packer/Unsafe.hs
+++ b/Data/Packer/Unsafe.hs
@@ -18,7 +18,7 @@
 import Data.Packer.Internal
 import Foreign.Ptr
 import Foreign.ForeignPtr
-import Control.Monad.State
+import Control.Monad
 import Control.Exception
 import Control.Concurrent.MVar (takeMVar, newMVar)
 
diff --git a/packer.cabal b/packer.cabal
--- a/packer.cabal
+++ b/packer.cabal
@@ -1,5 +1,5 @@
 Name:                packer
-Version:             0.1.7
+Version:             0.1.8
 Description:         Fast byte serializer and unserializer
 License:             BSD3
 License-file:        LICENSE
@@ -17,7 +17,7 @@
   Build-Depends:     base >= 3 && < 5
                    , bytestring
                    , ghc-prim
-                   , mtl
+                   , transformers
   Exposed-modules:   Data.Packer
                      Data.Packer.Unsafe
                      Data.Packer.IO