anchor.diff:  { lib, stdenv, unzip, fetchurl, electron_6, makeWrapper, geogebra }:
   let
     pname = "geogebra";
  -  version = "6-0-620-0";
  +  version = "6-0-631-0";
   
     srcIcon = geogebra.srcIcon;
     desktopItem = geogebra.desktopItem;
  
positive.code:     src = fetchurl {
        urls = [
          "https://download.geogebra.org/installers/6.0/GeoGebra-Linux64-Portable-${version}.zip"
          "https://web.archive.org/web/20210101214511/https://download.geogebra.org/installers/6.0/GeoGebra-Linux64-Portable-${version}.zip"
        ];
        sha256 = "0xxzmphbfvmhnxnc1pkjgdhccjndyzmlvvaa8xfdrvswwwk7zh43";
      };
  
      dontConfigure = true;
  
negative.code:     src = fetchurl {
        urls = [
          "https://download.geogebra.org/installers/6.0/GeoGebra-Classic-6-MacOS-Portable-${version}.zip"
          "https://web.archive.org/web/20210406084052/https://download.geogebra.org/installers/6.0/GeoGebra-Classic-6-MacOS-Portable-${version}.zip"
        ];
        sha256 = "0fa680yyz4nry1xvb9v6qqh1mib6grff5d3p7d90nyjlv101p262";
      };
  
      dontUnpack = true;
  