gistfile1.txt

diff --git c/pkgs/applications/networking/instant-messengers/mattermost-desktop/default.nix i/pkgs/applications/networking/instant-messengers/mattermost-desktop/default.nix
index 6f4e7e5b677..f74cb3044b6 100644
--- c/pkgs/applications/networking/instant-messengers/mattermost-desktop/default.nix
+++ i/pkgs/applications/networking/instant-messengers/mattermost-desktop/default.nix
@@ -3,6 +3,8 @@ freetype, fontconfig, dbus, libX11, xorg, libXi, libXcursor, libXdamage,
 libXrandr, libXcomposite, libXext, libXfixes, libXrender, libXtst,
 libXScrnSaver, nss, nspr, alsaLib, cups, expat, udev }:
 let
+  pname = "mattermost-desktop";
+  version = "4.2.3";
   rpath = stdenv.lib.makeLibraryPath [
     alsaLib
     atk
@@ -36,20 +38,18 @@ let
   ];
 
 in
-  stdenv.mkDerivation rec {
-    pname = "mattermost-desktop";
-    version = "4.2.0";
-
+  stdenv.mkDerivation {
+    inherit pname version;
     src =
       if stdenv.hostPlatform.system == "x86_64-linux" then
         fetchurl {
           url = "https://releases.mattermost.com/desktop/${version}/${pname}-${version}-linux-x64.tar.gz";
-          sha256 = "0hka94gwpscjn61032c0grpjv5gjb0j8rkx6pgwci617n29xkyf6";
+          sha256 = "14xyn8dp0xxl4j9xdsjik9p6srqdxbirgcgym2sv64p01w3kc9wf";
         }
       else if stdenv.hostPlatform.system == "i686-linux" then
         fetchurl {
           url = "https://releases.mattermost.com/desktop/${version}/${pname}-${version}-linux-ia32.tar.gz";
-          sha256 = "1nx2sgbnr60h6kn56wv54m7cvyx27d64bfprpb94hqd5c2z21x80";
+          sha256 = "063rrxw76mjz71wp9xd3ppkq3s017vrzms879r2cilypmay7fhgs";
         }
       else
         throw "Mattermost-Desktop is not currently supported on ${stdenv.hostPlatform.system}";