let requiredVersion = import ./lib/minver.nix; in if ! builtins ? nixVersion || builtins.compareVersions requiredVersion builtins.nixVersion == 1 then abort '' This version of Nixpkgs requires Nix >= ${requiredVersion}, please upgrade: - If you are running NixOS, `nixos-rebuild' can be used to upgrade your system. - Alternatively, with Nix > 2.0 `nix upgrade-nix' can be used to imperatively upgrade Nix. You may use `nix-env --version' to check which version you have. - If you installed Nix using the install script (https://nixos.org/nix/install), it is safe to upgrade by running it again: curl -L https://nixos.org/nix/install | sh For more information, please see the NixOS release notes at https://nixos.org/nixos/manual or locally at ${toString ./nixos/doc/manual/release-notes}. If you need further help, see https://nixos.org/nixos/support.html '' else import ./pkgs/top-level/impure.nix