{
  description = "A very basic flake";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
    nixpkgs-old.url = "github:nixos/nixpkgs?ref=nixos-unstable";
  };

  outputs =
    {
      self,
      nixpkgs,
      nixpkgs-old,
    }:
    let
      forAllSystems =
        f: nixpkgs.lib.genAttrs [ "x86_64-linux" "aarch64-linux" ] (sys: let pkgs = import nixpkgs {system = sys; overlays = [self.overlays.default];}; in f pkgs);
      overlayBaseInstance = import ./overlay.nix nixpkgs.outPath;
      myOverlay =
        pkgs:
        overlayBaseInstance {
          inherit pkgs;
          oldPkgs = nixpkgs-old.legacyPackages.${pkgs.hostPlatform.system};
        };
    in
    {
      overlays.default = final: _: myOverlay final;

      legacyPackages = forAllSystems (pkgs: myOverlay pkgs);
    };
}