diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,5 +1,9 @@
 `generics-eot` is a library for datatype generic programming that tries to be
-very simple to understand and use. It's heavily inspired by the awesome
-[`generics-sop`](http://hackage.haskell.org/package/generics-sop) package.
+very simple to understand and use.
 
 Documentation can be found here: https://generics-eot.readthedocs.io/
+
+## Alternatives
+
+- [`generics-sop`](http://hackage.haskell.org/package/generics-sop) - `generics-eot` is heavily inspired by this awesome package.
+- There's a fork of `generics-eot` vendored into [`knit`](https://github.com/pkamenarsky/knit): [`knit/vendor/generics-eot`](https://github.com/pkamenarsky/knit/tree/master/vendor/generics-eot). It gives access to field names of record types at the type-level, which the version at [github.com/soenkehahn/generics-eot](https://github.com/soenkehahn/generics-eot) does not. For more discussion, see [here](https://github.com/soenkehahn/generics-eot/pull/26).
diff --git a/examples/Catamorphisms.hs b/examples/Catamorphisms.hs
--- a/examples/Catamorphisms.hs
+++ b/examples/Catamorphisms.hs
@@ -8,6 +8,7 @@
 
 module Catamorphisms where
 
+import           Data.Kind
 import           Generics.Eot
 
 catamorphism :: (HasEot a, Cata (Eot a) dest) =>
@@ -15,7 +16,7 @@
 catamorphism a proxy = cata (toEot a) proxy
 
 class Cata eot dest where
-  type Typ eot dest :: *
+  type Typ eot dest :: Type
   cata :: eot -> Proxy dest -> Typ eot dest
   cataConst :: Proxy eot -> dest -> Typ eot dest
 
@@ -39,7 +40,7 @@
   cataConst Proxy = id
 
 class Cons fields dest where
-  type ConsFunc fields dest :: *
+  type ConsFunc fields dest :: Type
   eotConsFunc :: ConsFunc fields dest -> fields -> dest
 
 instance Cons () dest where
diff --git a/generics-eot.cabal b/generics-eot.cabal
--- a/generics-eot.cabal
+++ b/generics-eot.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.31.1.
+-- This file has been generated from package.yaml by hpack version 0.38.2.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 50d659af680069ec9917ed6a35c1ca01a40f9e83cc751ac1801a407b1e7a0602
+-- hash: 61b1b8512afc75a1284a5d2b9a257971eb7121e996fc24221e1c3e6c2b6470a4
 
 name:           generics-eot
-version:        0.4.0.1
+version:        0.4.1.0
 synopsis:       A library for generic programming that aims to be easy to understand
 description:    Documentation is here: <https://generics-eot.readthedocs.io/>
 category:       Generics
diff --git a/src/Generics/Eot.hs b/src/Generics/Eot.hs
--- a/src/Generics/Eot.hs
+++ b/src/Generics/Eot.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE UndecidableInstances #-}
 
 -- | @generics-eot@ tries to be a library for datatype generic programming
@@ -24,9 +25,9 @@
   absurd,
   ) where
 
+import           Data.Kind
 import           Data.Proxy
 import           Data.Void
-import           GHC.Exts (Constraint)
 import           GHC.Generics hiding (Datatype, Constructor)
 
 import           Generics.Eot.Datatype
@@ -66,7 +67,7 @@
   -- These rules (and the end-markers) are necessary to make sure generic
   -- functions know exactly which parts of the generic representation are field
   -- types and which parts belong to the generic skeleton.
-  type Eot a :: *
+  type Eot a :: Type
 
   -- | Convert a value of type @a@ to its generic representation.
   toEot :: a -> Eot a
diff --git a/src/Generics/Eot/Datatype.hs b/src/Generics/Eot/Datatype.hs
--- a/src/Generics/Eot/Datatype.hs
+++ b/src/Generics/Eot/Datatype.hs
@@ -12,6 +12,7 @@
 module Generics.Eot.Datatype where
 
 import           Data.Maybe
+import           Data.Kind
 import           Data.Proxy
 import qualified GHC.Generics as GHC
 import           GHC.Generics hiding (Datatype(..), Constructor(..))
@@ -45,7 +46,7 @@
 
 -- * datatype
 
-class GenericDatatype (a :: * -> *) where
+class GenericDatatype (a :: Type -> Type) where
   datatypeC :: Proxy a -> Datatype
 
 instance (GHC.Datatype c, GenericConstructors f) =>
@@ -57,7 +58,7 @@
 
 -- * constructors
 
-class GenericConstructors (a :: * -> *) where
+class GenericConstructors (a :: Type -> Type) where
   getConstructors :: Proxy a -> [Constructor]
 
 instance (GenericConstructors a, GenericConstructors b) =>
@@ -85,7 +86,7 @@
   l@(Nothing : _) -> NoSelectors (length l)
   l@(Just _ : _) -> Selectors (catMaybes l)
 
-class GenericFields (a :: * -> *) where
+class GenericFields (a :: Type -> Type) where
   getFieldsC :: Proxy a -> [Maybe String]
 
 instance (GenericFields a, GenericFields b) =>
diff --git a/src/Generics/Eot/Eot.hs b/src/Generics/Eot/Eot.hs
--- a/src/Generics/Eot/Eot.hs
+++ b/src/Generics/Eot/Eot.hs
@@ -17,14 +17,15 @@
   HasEotG(..),
   ) where
 
+import           Data.Kind
 import           Data.Proxy
 import           Data.Void
 import           GHC.Generics
 
 -- * datatype
 
-class HasEotG (a :: * -> *) where
-  type EotG a :: *
+class HasEotG (a :: Type -> Type) where
+  type EotG a :: Type
   toEotG :: a x -> EotG a
   fromEotG :: EotG a -> a x
 
@@ -35,8 +36,8 @@
 
 -- * constructors
 
-class HasConstructorsG (a :: * -> *) where
-  type Constructors a :: *
+class HasConstructorsG (a :: Type -> Type) where
+  type Constructors a :: Type
   toEotConstructors :: a x -> Constructors a
   fromEotConstructors :: Constructors a -> a x
 
@@ -65,7 +66,7 @@
 -- * GEither
 
 class Normalize a b where
-  type GEither a b :: *
+  type GEither a b :: Type
   gLeft :: a -> Proxy b -> GEither a b
   gRight :: Proxy a -> b -> GEither a b
   gEither :: GEither a b -> Either a b
@@ -91,8 +92,8 @@
 
 -- * fields
 
-class HasFieldsG (a :: * -> *) where
-  type Fields a :: *
+class HasFieldsG (a :: Type -> Type) where
+  type Fields a :: Type
   toEotFields :: a x -> Fields a
   fromEotFields :: Fields a -> a x
 
@@ -116,7 +117,7 @@
 -- * heterogenous lists
 
 class Concat a b where
-  type a +++ b :: *
+  type a +++ b :: Type
   (+++) :: a -> b -> (a +++ b)
   unConcat :: (a +++ b) -> (a, b)
 
diff --git a/test/Generics/Eot/Tutorial.lhs b/test/Generics/Eot/Tutorial.lhs
--- a/test/Generics/Eot/Tutorial.lhs
+++ b/test/Generics/Eot/Tutorial.lhs
@@ -466,11 +466,10 @@
 
 ``` haskell
 -- $ >>> putStrLn $ createTableStatement (Proxy :: Proxy A)
--- <BLANKLINE>
 -- ...
---     • No instance for (EotCreateTableStatement
+--     • No instance for ‘EotCreateTableStatement
 --                          Datatype
---                          (Either ([Char], (Int, ())) (Either (Int, (Bool, ())) Void)))
+--                          (Either ([Char], (Int, ())) (Either (Int, (Bool, ())) Void))’
 --         arising from a use of ‘createTableStatement’
 -- ...
 ```
diff --git a/test/Generics/Eot/TutorialSpec.hs b/test/Generics/Eot/TutorialSpec.hs
--- a/test/Generics/Eot/TutorialSpec.hs
+++ b/test/Generics/Eot/TutorialSpec.hs
@@ -1,9 +1,5 @@
-{-# LANGUAGE CPP #-}
-
 module Generics.Eot.TutorialSpec where
 
-#if MIN_VERSION_base(4,9,0)
-
 import           Test.DocTest
 import           Test.Hspec
 
@@ -14,14 +10,3 @@
 
   it "doctests" $ do
     doctest (words "test/Generics/Eot/Tutorial.lhs -isrc -pgmL markdown-unlit")
-
-#else
-
-import           Test.Hspec
-
-import           Generics.Eot.Tutorial ()
-
-spec :: Spec
-spec = return ()
-
-#endif