anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "cmdstan";
  -  version = "2.17.1";
  +  version = "2.29.2";
   
  +  # includes stanc binaries needed to build cmdstand
     src = fetchurl {
       url = "https://github.com/stan-dev/cmdstan/releases/download/v${version}/cmdstan-${version}.tar.gz";
  -    sha256 = "1vq1cnrkvrvbfl40j6ajc60jdrjcxag1fi6kff5pqmadfdz9564j";
  +    sha256 = "sha256-VntTH6c//fcGyqF+szROHftB6GmTyvi6QIdf+RAzUVM=";
     };
   
     buildFlags = [ "build" ];
  
positive.code: 
    doCheck = true;
    checkInputs = [ python3 ];
    checkPhase = "python ./runCmdStanTests.py src/test/interface"; # see #5368
  
    installPhase = ''
      mkdir -p $out/opt $out/bin
  
negative.code:     EOF
      chmod a+x $out/bin/stan
    '';
  
    # Hack to ensure that patchelf --shrink-rpath get rids of a $TMPDIR reference.
    preFixup = "rm -rf $(pwd)";
  
    meta = {
      description = "Command-line interface to Stan";
  