diff --git a/pkgs/tools/admin/realvnc-vnc-viewer/default.nix b/pkgs/tools/admin/realvnc-vnc-viewer/default.nix
index 690c215471c..2e8eabfc1a3 100644
--- a/pkgs/tools/admin/realvnc-vnc-viewer/default.nix
+++ b/pkgs/tools/admin/realvnc-vnc-viewer/default.nix
@@ -2,18 +2,18 @@
 
 stdenv.mkDerivation rec {
   pname = "realvnc-vnc-viewer";
-  version = "6.21.406";
+  version = "6.21.920";
 
   src = {
     "x86_64-linux" = fetchurl {
       url = "https://www.realvnc.com/download/file/viewer.files/VNC-Viewer-${version}-Linux-x64.rpm";
-      sha256 = "0rnizzanaykqg1vfy56p8abc4fmgpbibj54j4c1v81zsj3kmahka";
+      sha256 = "1qghc5380h4b2pczksmky3kcffz5wn9shw033w4f969wl96p31fz";
     };
     "i686-linux" = fetchurl {
       url = "https://www.realvnc.com/download/file/viewer.files/VNC-Viewer-${version}-Linux-x86.rpm";
-      sha256 = "1rlxfiqymi1licn2spyiqa00kiwzhdr0pkh7vv3ai6gb9f6phk31";
+      sha256 = "034iwqxpqhnm6i292fakva7vkwrrzamwcvbm7xyccpd54adj0grn";
     };
-  }.${stdenv.system};
+  }.${stdenv.system} or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
 
   nativeBuildInputs = [ autoPatchelfHook rpmextract ];
   buildInputs = [ libX11 libXext ];