diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog for `newtype-generics`
 
+## [0.6] – 2021-02-04
+- Remove the deprecated `Control.Newtype` module.
+- Support GHC-9.0
+
 ## [0.5.4] – 2019-09-10
 - Add `Newtype` instance for `Data.Monoid.Ap`.
 - Support GHC-8.8.
@@ -36,7 +40,8 @@
 - Relax types of `underF` and `overF` to allow different input & output functors
 
 
-[Unreleased]: https://github.com/sjakobi/newtype-generics/compare/v0.5.4...HEAD
+[Unreleased]: https://github.com/sjakobi/newtype-generics/compare/v0.6...HEAD
+[0.6]: https://github.com/sjakobi/newtype-generics/compare/v0.5.4...v0.6
 [0.5.4]: https://github.com/sjakobi/newtype-generics/compare/v0.5.3...v0.5.4
 [0.5.3]: https://github.com/sjakobi/newtype-generics/compare/v0.5.2.2...v0.5.3
 [0.5.2.2]: https://github.com/sjakobi/newtype-generics/compare/v0.5.2.1...v0.5.2.2
diff --git a/Control/Newtype.hs b/Control/Newtype.hs
deleted file mode 100644
--- a/Control/Newtype.hs
+++ /dev/null
@@ -1,6 +0,0 @@
-module Control.Newtype
-{-# deprecated "Import \"Control.Newtype.Generics\" instead" #-}
-  ( module Control.Newtype.Generics
-  ) where
-
-import Control.Newtype.Generics
diff --git a/Control/Newtype/Generics.hs b/Control/Newtype/Generics.hs
--- a/Control/Newtype/Generics.hs
+++ b/Control/Newtype/Generics.hs
@@ -60,15 +60,12 @@
 import Control.Arrow
 import Data.Functor.Compose
 import Data.Functor.Identity
-#if MIN_VERSION_base(4,7,0)
 import Data.Fixed
-#endif
+import Data.Kind (Type)
 import Data.Monoid
 import Data.Ord
-#if MIN_VERSION_base(4,9,0)
 import qualified Data.Semigroup
 import Data.Semigroup (Min(..), Max(..), WrappedMonoid(..), Option(..))
-#endif
 import GHC.Generics
 {-import Generics.Deriving-}
 
@@ -84,7 +81,7 @@
 
 -- Generic Newtype
 class GNewtype n where
-  type GO n :: *
+  type GO n :: Type
   gpack   :: GO n -> n p
   gunpack :: n p  -> GO n
 
@@ -105,7 +102,7 @@
 -- | As long as the type @n@ is an instance of Generic, you can create an instance
 -- with just @instance Newtype n@
 class Newtype n where
-  type O n :: *
+  type O n :: Type
   type O n = GO (Rep n)
 
   pack   :: O n -> n
@@ -240,7 +237,6 @@
   pack = ArrowMonad
   unpack (ArrowMonad a) = a
 
-#if MIN_VERSION_base(4,7,0)
 -- Instances from Data.Fixed
 
 -- | @since 0.5.1
@@ -248,7 +244,6 @@
   type O (Fixed a) = Integer
   pack = MkFixed
   unpack (MkFixed x) = x
-#endif
 
 -- Instances from Data.Functor.Compose
 
@@ -316,16 +311,14 @@
   pack = Last
   unpack (Last a) = a
 
-#if MIN_VERSION_base(4,8,0)
 -- | @since 0.5.1
 instance Newtype (Alt f a) where
   type O (Alt f a) = f a
   pack = Alt
   unpack (Alt x) = x
-#endif
 
 #if MIN_VERSION_base(4,12,0)
--- | @since Unreleased
+-- | @since 0.5.4
 instance Newtype (Ap f a) where
   type O (Ap f a) = f a
   pack = Ap
@@ -341,7 +334,6 @@
   unpack (Down a) = a
 
 
-#if MIN_VERSION_base(4,9,0)
 -- Instances from Data.Semigroup
 
 -- | @since 0.5.1
@@ -379,4 +371,3 @@
   type O (Option a) = Maybe a
   pack = Option
   unpack (Option x) = x
-#endif
diff --git a/newtype-generics.cabal b/newtype-generics.cabal
--- a/newtype-generics.cabal
+++ b/newtype-generics.cabal
@@ -1,5 +1,5 @@
 Name:                newtype-generics
-Version:             0.5.4
+Version:             0.6
 Synopsis:            A typeclass and set of functions for working with newtypes
 Description:         Per Conor McBride, the Newtype typeclass represents the packing and unpacking of a newtype,
                      and allows you to operate under that newtype with functions such as ala.
@@ -15,19 +15,17 @@
 Extra-source-files:  CHANGELOG.md
 Cabal-version:       >=1.10
 Tested-with:
-  GHC==8.8.1,
+  -- GHC==9.0.1,
+  GHC==8.10.3,
+  GHC==8.8.4,
   GHC==8.6.5,
   GHC==8.4.4,
   GHC==8.2.2,
-  GHC==8.0.2,
-  GHC==7.10.3,
-  GHC==7.8.4,
-  GHC==7.6.3
+  GHC==8.0.2
 
 Library
-  Exposed-modules:     Control.Newtype
-                     , Control.Newtype.Generics
-  Build-depends:       base >= 4.6 && < 4.14
+  Exposed-modules:     Control.Newtype.Generics
+  Build-depends:       base >= 4.9 && < 4.16
                      , transformers < 0.6
   Ghc-options: -Wall
   default-language:   Haskell2010