anchor.diff:  
   let
   
  -  major = "2020";
  -  minor = "11";
  -  patch = "23";
  +  major = "2021";
  +  minor = "03";
  +  patch.seriousproton = "30";
  +  patch.emptyepsilon = "31";
   
  -  version = "${major}.${minor}.${patch}";
  +  version.seriousproton = "${major}.${minor}.${patch.seriousproton}";
  +  version.emptyepsilon = "${major}.${minor}.${patch.emptyepsilon}";
   
     serious-proton = stdenv.mkDerivation {
       pname = "serious-proton";
  -    inherit version;
  +    version = version.seriousproton;
   
       src = fetchFromGitHub {
         owner = "daid";
         repo = "SeriousProton";
  -      rev = "EE-${version}";
  -      sha256 = "sha256-/gwJPlvvOCv5XIsiVgZ8Eb/7vgwG/V+s/soGVCfYrwo=";
  +      rev = "EE-${version.seriousproton}";
  +      sha256 = "sha256-wxb/CxJ/HKsVngeahjygZFPMMxitkHdVD0EQ3svxgIU=";
       };
   
       nativeBuildInputs = [ cmake ];
  
positive.code: 
  stdenv.mkDerivation {
    pname = "empty-epsilon";
    inherit version;
  
    src = fetchFromGitHub {
      owner = "daid";
      repo = "EmptyEpsilon";
      rev = "EE-${version}";
      sha256 = "sha256-HbF6xThR+ogNHbAcXF03DaBhwVhNEr5BJO7jeeVZH/o=";
    };
  
    nativeBuildInputs = [ cmake ];
  
negative.code: 
    cmakeFlags = [
      "-DSERIOUS_PROTON_DIR=${serious-proton.src}"
      "-DCPACK_PACKAGE_VERSION=${version.emptyepsilon}"
      "-DCPACK_PACKAGE_VERSION_MAJOR=${major}"
      "-DCPACK_PACKAGE_VERSION_MINOR=${minor}"
      "-DCPACK_PACKAGE_VERSION_PATCH=${patch.emptyepsilon}"
    ];
  
    meta = with lib; {
  