diff --git a/bench/Benchmark.hs b/bench/Benchmark.hs
--- a/bench/Benchmark.hs
+++ b/bench/Benchmark.hs
@@ -2,14 +2,10 @@
 {-# LANGUAGE PolyKinds #-}
 module Main (main) where
 
-import Control.DeepSeq
 import Control.Lens
 import Criterion.Main
 import Data.Dynamic
 import Data.Union
-
-instance NFData (Proxy (a :: k)) where
-  rnf Proxy = ()
 
 union1 :: OpenUnion '[(), Proxy 0, Proxy 1]
 union1 = openUnion # ()
diff --git a/union.cabal b/union.cabal
--- a/union.cabal
+++ b/union.cabal
@@ -1,5 +1,5 @@
 name:                union
-version:             0.1.1.0
+version:             0.1.1.1
 synopsis:            Extensible type-safe unions
 description:
 
@@ -52,7 +52,7 @@
   build-depends:       base
                ,       union
                ,       lens
-               ,       deepseq
+               ,       deepseq >=1.4.2
                ,       criterion
   hs-source-dirs:      bench
   default-language:    Haskell2010