diff --git a/pkgs/development/libraries/haskell/attoparsec/0.12.0.0.nix b/pkgs/development/libraries/haskell/attoparsec/0.12.1.0.nix
similarity index 86%
rename from pkgs/development/libraries/haskell/attoparsec/0.12.0.0.nix
rename to pkgs/development/libraries/haskell/attoparsec/0.12.1.0.nix
index 6fd32736c4d8..72a58b1cce65 100644
--- a/pkgs/development/libraries/haskell/attoparsec/0.12.0.0.nix
+++ b/pkgs/development/libraries/haskell/attoparsec/0.12.1.0.nix
@@ -4,8 +4,8 @@
 
 cabal.mkDerivation (self: {
   pname = "attoparsec";
-  version = "0.12.0.0";
-  sha256 = "04wdb2i2yqybkfnjs3f25nf7xz1nq5sn8z23klbm4xnqaiajmkmr";
+  version = "0.12.1.0";
+  sha256 = "1y7sikk5hg9yj3mn21k026ni6lznsih0lx03rgdz4gmb6aqh54bn";
   buildDepends = [ deepseq scientific text ];
   testDepends = [
     deepseq QuickCheck scientific testFramework
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index daea93d3aa7d..803dc897eb7f 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -193,8 +193,8 @@ self : let callPackage = x : y : modifyPrio (newScope self x y); in
   attoparsec_0_10_4_0 = callPackage ../development/libraries/haskell/attoparsec/0.10.4.0.nix {};
   attoparsec_0_11_3_1 = callPackage ../development/libraries/haskell/attoparsec/0.11.3.1.nix {};
   attoparsec_0_11_3_4 = callPackage ../development/libraries/haskell/attoparsec/0.11.3.4.nix {};
-  attoparsec_0_12_0_0 = callPackage ../development/libraries/haskell/attoparsec/0.12.0.0.nix {};
-  attoparsec = self.attoparsec_0_12_0_0;
+  attoparsec_0_12_1_0 = callPackage ../development/libraries/haskell/attoparsec/0.12.1.0.nix {};
+  attoparsec = self.attoparsec_0_12_1_0;
 
   attoparsecBinary = callPackage ../development/libraries/haskell/attoparsec-binary {};