diff --git a/pkgs/development/libraries/haskell/transformers/0.4.1.0.nix b/pkgs/development/libraries/haskell/transformers/0.4.2.0.nix
similarity index 81%
rename from pkgs/development/libraries/haskell/transformers/0.4.1.0.nix
rename to pkgs/development/libraries/haskell/transformers/0.4.2.0.nix
index d705040387b..3557941a9a8 100644
--- a/pkgs/development/libraries/haskell/transformers/0.4.1.0.nix
+++ b/pkgs/development/libraries/haskell/transformers/0.4.2.0.nix
@@ -4,8 +4,8 @@
 
 cabal.mkDerivation (self: {
   pname = "transformers";
-  version = "0.4.1.0";
-  sha256 = "0jlnz86f87jndv4sifg1zpv5b2g2cxy1x2575x727az6vyaarwwg";
+  version = "0.4.2.0";
+  sha256 = "0a364zfcm17mhpy0c4ms2j88sys4yvgd6071qsgk93la2wjm8mkr";
   noHaddock = self.stdenv.lib.versionOlder self.ghc.version "6.11";
   meta = {
     description = "Concrete functor and monad transformers";
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index 2a08bdf4847..02271e27f8a 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -2628,7 +2628,7 @@ self : let callPackage = x : y : modifyPrio (newScope self x y); in
   tostring = callPackage ../development/libraries/haskell/tostring {};
 
   transformers_0_3_0_0 = callPackage ../development/libraries/haskell/transformers/0.3.0.0.nix {};
-  transformers_0_4_1_0 = callPackage ../development/libraries/haskell/transformers/0.4.1.0.nix {};
+  transformers_0_4_2_0 = callPackage ../development/libraries/haskell/transformers/0.4.2.0.nix {};
   transformers = null;          # core package since ghc >= 7.8.x
 
   transformersBase = callPackage ../development/libraries/haskell/transformers-base {};