diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+# 0.3.3.0
+
+- Enable `PolyKinds` to generalize `Proxy`, `Tagged`, and `Const` instances.
+
 # 0.3.2.0
 
 - Introduce instances from `aeson-0.11.1.0`: `Const`, `Tagged`, `Proxy` and `NonEmpty`
diff --git a/aeson-compat.cabal b/aeson-compat.cabal
--- a/aeson-compat.cabal
+++ b/aeson-compat.cabal
@@ -1,9 +1,9 @@
--- This file has been generated from package.yaml by hpack version 0.11.2.
+-- This file has been generated from package.yaml by hpack version 0.13.0.
 --
 -- see: https://github.com/sol/hpack
 
 name:           aeson-compat
-version:        0.3.2.0
+version:        0.3.3.0
 synopsis:       Compatibility layer for aeson
 description:    Compatibility layer for @aeson@
 category:       Web
@@ -32,7 +32,7 @@
   build-depends:
       base                     >=4.6  && <4.10
     , base-compat              >=0.6.0 && <0.10
-    , aeson                    >=0.7.0.6 && <0.11.2
+    , aeson                    >=0.7.0.6 && <0.11.3
     , attoparsec               >=0.12 && <0.14
     , bytestring               >=0.10 && <0.11
     , containers               >=0.5  && <0.6
@@ -62,7 +62,7 @@
   build-depends:
       base                     >=4.6  && <4.10
     , base-compat              >=0.6.0 && <0.10
-    , aeson                    >=0.7.0.6 && <0.11.2
+    , aeson                    >=0.7.0.6 && <0.11.3
     , attoparsec               >=0.12 && <0.14
     , bytestring               >=0.10 && <0.11
     , containers               >=0.5  && <0.6
diff --git a/src/Data/Aeson/Compat.hs b/src/Data/Aeson/Compat.hs
--- a/src/Data/Aeson/Compat.hs
+++ b/src/Data/Aeson/Compat.hs
@@ -1,6 +1,7 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PolyKinds #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 -----------------------------------------------------------------------------
 -- |