anchor.diff:             if stdenv.isi686 then "x86-32" else
              if stdenv.isAarch64 then "armv8" else
              "unknown";
  -    version = "13";
   
  -    nnueFile = "nn-62ef826d1a6d.nnue";
  +    nnueFile = "nn-3475407dc199.nnue";
       nnue = fetchurl {
         name = nnueFile;
         url = "https://tests.stockfishchess.org/api/nn/${nnueFile}";
  -      sha256 = "0qsy9rr4zgxrpgwhwbi96z01a2560am2b00q2klbj4bd39nq5vv2";
  +      sha256 = "sha256-NHVAfcGZc+pERnZ4Y0zOAj1iDkGXcMERzIk3/maJ7Ic=";
       };
   in
   
  -stdenv.mkDerivation {
  +stdenv.mkDerivation rec {
     pname = "stockfish";
  -  inherit version;
  +  version = "14";
   
  -  src = fetchurl {
  -    url = "https://github.com/official-stockfish/Stockfish/archive/sf_${version}.tar.gz";
  -    sha256 = "0qhxp2w543psanzhzn8jhfafx8aip57v9nsvafbwa5xynchlgl8m";
  +  src = fetchFromGitHub {
  +    owner = "official-stockfish";
  +    repo = "Stockfish";
  +    rev = "sf_${version}";
  +    sha256 = "sha256-fX0Tr1yqjmNRSxmisFRKUY1E5//qF3zAfJ8innAeyxA=";
     };
   
     # This addresses a linker issue with Darwin
     # https://github.com/NixOS/nixpkgs/issues/19098
  -  preBuild = optionalString stdenv.isDarwin ''
  +  preBuild = lib.optionalString stdenv.isDarwin ''
       sed -i.orig '/^\#\#\# 3.*Link Time Optimization/,/^\#\#\# 3/d' Makefile
     '';
   
  
positive.code: { lib, stdenv, fetchurl }:
  
  with lib;
  
  let
      # The x86-64-modern may need to be refined further in the future
  
negative.code: 
    enableParallelBuilding = true;
  
    meta = with lib; {
      homepage = "https://stockfishchess.org/";
      description = "Strong open source chess engine";
      longDescription = ''
  