diff --git a/Network/Wreq/Internal/Types.hs b/Network/Wreq/Internal/Types.hs
--- a/Network/Wreq/Internal/Types.hs
+++ b/Network/Wreq/Internal/Types.hs
@@ -45,7 +45,7 @@
 
 import Control.Exception (Exception)
 import Data.IORef (IORef)
-import Data.Monoid ((<>))
+import Data.Monoid ((<>), mconcat)
 import Data.Text (Text)
 import Data.Time.Clock (UTCTime)
 import Data.Typeable (Typeable)
diff --git a/Network/Wreq/Types.hs b/Network/Wreq/Types.hs
--- a/Network/Wreq/Types.hs
+++ b/Network/Wreq/Types.hs
@@ -40,7 +40,7 @@
 import Control.Lens ((&), (.~))
 import Data.Aeson (Value, encode)
 import Data.Int (Int8, Int16, Int32, Int64)
-import Data.Word (Word8, Word16, Word32, Word64)
+import Data.Word (Word, Word8, Word16, Word32, Word64)
 import Network.HTTP.Client (Request)
 import Network.HTTP.Client.MultipartFormData (Part, formDataBody)
 import Network.Wreq.Internal.Types
diff --git a/wreq.cabal b/wreq.cabal
--- a/wreq.cabal
+++ b/wreq.cabal
@@ -1,5 +1,5 @@
 name:                wreq
-version:             0.5.0.0
+version:             0.5.0.1
 synopsis:            An easy-to-use HTTP client library.
 description:
   .