diff --git a/pkgs/development/python-modules/marionette-harness/mozprocess.nix b/pkgs/development/python-modules/marionette-harness/mozprocess.nix
index e8130e8038fd..cfa0f7666201 100644
--- a/pkgs/development/python-modules/marionette-harness/mozprocess.nix
+++ b/pkgs/development/python-modules/marionette-harness/mozprocess.nix
@@ -6,11 +6,11 @@
 
 buildPythonPackage rec {
   pname = "mozprocess";
-  version = "0.26";
+  version = "1.0.0";
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "9f471c45bee9ff14e936c6ee216a6cc4941223659c01fa626bce628001d8485c";
+    sha256 = "a0fd8367e663d3cac74ee46bffa789667bc8d52f242d81a14522205fa6650cb2";
   };
 
   propagatedBuildInputs = [ mozinfo ];