diff --git a/pkgs/development/libraries/haskell/io-streams/default.nix b/pkgs/development/libraries/haskell/io-streams/default.nix
index 4b5d9bab9be..6d1d3cbfb6b 100644
--- a/pkgs/development/libraries/haskell/io-streams/default.nix
+++ b/pkgs/development/libraries/haskell/io-streams/default.nix
@@ -8,8 +8,8 @@
 
 cabal.mkDerivation (self: {
   pname = "io-streams";
-  version = "1.1.4.6";
-  sha256 = "0vn6vlgfapmyd9y87i9i0y480w8w81xd3lnhh66a6lalskd4bjdw";
+  version = "1.2.0.0";
+  sha256 = "1lisvwy4pj0ywm1i61qan3vxisl4xazz7z8i8iybww1dv3j6mrn2";
   buildDepends = [
     attoparsec blazeBuilder network primitive text time transformers
     vector zlibBindings