diff --git a/pkgs/development/libraries/haskell/machines/default.nix b/pkgs/development/libraries/haskell/machines/default.nix
index 02b2ec272b0..bb01e9f655e 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 = "0.4.0.1";
-  sha256 = "11h1b6hls7v4ifz3p7v1gdsgxqgyx92v978pjfyp81ianwjyclqg";
+  version = "0.4.1";
+  sha256 = "1wripnvpzfdnf7i2aygjyh33cp7srkb5638snwyn700bjbi2j7gb";
   buildDepends = [
     comonad free mtl pointed profunctors semigroups transformers void
   ];