diff --git a/pkgs/desktops/mate/mate-system-monitor/default.nix b/pkgs/desktops/mate/mate-system-monitor/default.nix
index c3f29dff631..5757f5eb9b4 100644
--- a/pkgs/desktops/mate/mate-system-monitor/default.nix
+++ b/pkgs/desktops/mate/mate-system-monitor/default.nix
@@ -2,11 +2,11 @@
 
 stdenv.mkDerivation rec {
   name = "mate-system-monitor-${version}";
-  version = "1.21.0";
+  version = "1.20.2";
 
   src = fetchurl {
     url = "http://pub.mate-desktop.org/releases/${mate.getRelease version}/${name}.tar.xz";
-    sha256 = "0filf6qyw4fk45br3cridbqdngwl525z49zn36r7q4agzhny4phz";
+    sha256 = "0f6sh23axzmcmyv0d837gbc0dixf1afh8951zrzp1y53rdgpa9qn";
   };
 
   nativeBuildInputs = [