``` environment = { systemPackages = let newerNixpkgs = import (pkgs.fetchzip { url = "https://github.com/NixOS/nixpkgs/archive/6a62663c601173e9cc2dd5bed91f1762415bb622.tar.gz"; sha256 = "0x8a43s9rb1jsfy8dnv01qg0jv07y46ks497q9i58w5g1pmhw20i"; }) { config = { }; }; in with pkgs; [ packages and stuff ]; }; ```