diff --git a/pkgs/development/libraries/haskell/machines/default.nix b/pkgs/development/libraries/haskell/machines/default.nix
index 1b391739c20..98a6248899b 100644
--- a/pkgs/development/libraries/haskell/machines/default.nix
+++ b/pkgs/development/libraries/haskell/machines/default.nix
@@ -6,8 +6,8 @@
 
 cabal.mkDerivation (self: {
   pname = "machines";
-  version = "0.2.5";
-  sha256 = "0745lhmfwq27nna517q7b82q59pda587wgh6840nw65syaj2qfhp";
+  version = "0.4";
+  sha256 = "00qs1hv1sc4278hlwjfv9ykbhxg4hxb0kqyrglagb42sn8j35kyz";
   buildDepends = [
     comonad free mtl pointed profunctors semigroups transformers void
   ];