diff --git a/Control/Applicative/Backwards.hs b/Control/Applicative/Backwards.hs
--- a/Control/Applicative/Backwards.hs
+++ b/Control/Applicative/Backwards.hs
@@ -2,7 +2,7 @@
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE Safe #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 710
diff --git a/Control/Monad/Signatures.hs b/Control/Monad/Signatures.hs
--- a/Control/Monad/Signatures.hs
+++ b/Control/Monad/Signatures.hs
@@ -2,7 +2,7 @@
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE Safe #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 -----------------------------------------------------------------------------
diff --git a/Control/Monad/Trans/Cont.hs b/Control/Monad/Trans/Cont.hs
--- a/Control/Monad/Trans/Cont.hs
+++ b/Control/Monad/Trans/Cont.hs
@@ -2,7 +2,7 @@
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE Safe #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 710
diff --git a/Control/Monad/Trans/Identity.hs b/Control/Monad/Trans/Identity.hs
--- a/Control/Monad/Trans/Identity.hs
+++ b/Control/Monad/Trans/Identity.hs
@@ -2,7 +2,7 @@
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE Safe #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 710
diff --git a/Control/Monad/Trans/Reader.hs b/Control/Monad/Trans/Reader.hs
--- a/Control/Monad/Trans/Reader.hs
+++ b/Control/Monad/Trans/Reader.hs
@@ -2,7 +2,7 @@
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE Safe #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 710
diff --git a/Data/Functor/Constant.hs b/Data/Functor/Constant.hs
--- a/Data/Functor/Constant.hs
+++ b/Data/Functor/Constant.hs
@@ -2,7 +2,7 @@
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE Safe #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 710
diff --git a/Data/Functor/Reverse.hs b/Data/Functor/Reverse.hs
--- a/Data/Functor/Reverse.hs
+++ b/Data/Functor/Reverse.hs
@@ -2,7 +2,7 @@
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE Safe #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 710
diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,5 +1,8 @@
 -*-change-log-*-
 
+0.5.0.1 Ross Paterson <R.Paterson@city.ac.uk> Jan 2016
+	* Tightened GHC bounds for PolyKinds and DeriveDataTypeable
+
 0.5.0.0 Ross Paterson <R.Paterson@city.ac.uk> Dec 2015
 	* Control.Monad.IO.Class in base for GHC >= 8.0
 	* Data.Functor.{Classes,Compose,Product,Sum} in base for GHC >= 8.0
diff --git a/legacy/pre709/Data/Functor/Identity.hs b/legacy/pre709/Data/Functor/Identity.hs
--- a/legacy/pre709/Data/Functor/Identity.hs
+++ b/legacy/pre709/Data/Functor/Identity.hs
@@ -1,15 +1,17 @@
 {-# LANGUAGE CPP #-}
-#if __GLASGOW_HASKELL__ >= 612
+#if __GLASGOW_HASKELL__ >= 700
 {-# LANGUAGE DeriveDataTypeable #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 702
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE Trustworthy #-}
 #endif
+#if __GLASGOW_HASKELL__ >= 706
+{-# LANGUAGE PolyKinds #-}
+#endif
 #if __GLASGOW_HASKELL__ >= 708
 {-# LANGUAGE AutoDeriveTypeable #-}
 {-# LANGUAGE DataKinds #-}
-{-# LANGUAGE PolyKinds #-}
 #endif
 -----------------------------------------------------------------------------
 -- |
@@ -47,7 +49,7 @@
 import Data.Foldable (Foldable(foldMap))
 import Data.Monoid (Monoid(mempty, mappend))
 import Data.Traversable (Traversable(traverse))
-#if __GLASGOW_HASKELL__ >= 612
+#if __GLASGOW_HASKELL__ >= 700
 import Data.Data
 #endif
 #if __GLASGOW_HASKELL__ >= 702
@@ -57,7 +59,7 @@
 -- | Identity functor and monad. (a non-strict monad)
 newtype Identity a = Identity { runIdentity :: a }
     deriving ( Eq, Ord
-#if __GLASGOW_HASKELL__ >= 612
+#if __GLASGOW_HASKELL__ >= 700
              , Data, Typeable
 #endif
 #if __GLASGOW_HASKELL__ >= 702
diff --git a/legacy/pre711/Data/Functor/Compose.hs b/legacy/pre711/Data/Functor/Compose.hs
--- a/legacy/pre711/Data/Functor/Compose.hs
+++ b/legacy/pre711/Data/Functor/Compose.hs
@@ -7,7 +7,7 @@
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE TypeOperators #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 708
diff --git a/legacy/pre711/Data/Functor/Product.hs b/legacy/pre711/Data/Functor/Product.hs
--- a/legacy/pre711/Data/Functor/Product.hs
+++ b/legacy/pre711/Data/Functor/Product.hs
@@ -7,7 +7,7 @@
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE TypeOperators #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 708
diff --git a/legacy/pre711/Data/Functor/Sum.hs b/legacy/pre711/Data/Functor/Sum.hs
--- a/legacy/pre711/Data/Functor/Sum.hs
+++ b/legacy/pre711/Data/Functor/Sum.hs
@@ -7,7 +7,7 @@
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE TypeOperators #-}
 #endif
-#if __GLASGOW_HASKELL__ >= 704
+#if __GLASGOW_HASKELL__ >= 706
 {-# LANGUAGE PolyKinds #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 708
diff --git a/transformers.cabal b/transformers.cabal
--- a/transformers.cabal
+++ b/transformers.cabal
@@ -1,5 +1,5 @@
 name:         transformers
-version:      0.5.0.0
+version:      0.5.0.1
 license:      BSD3
 license-file: LICENSE
 author:       Andy Gill, Ross Paterson