Flake registry for Eviny Fornybar, registry entries point to latest stable relese/branch.
Add nixConfig.flake-registry = "https://raw.githubusercontent.com/bkkp/flake-registry/main/flake-registry.json";
to top of your flake.
Then add for example nixpkgs to inputs args to your output function. Then you will get nixpkgs to point
to latest nixos stable branch. If you want another branch for example nixos-unstable, you can add the following
to yout flake:
inputs.nixpkgs.url = "nixpkgs/nixos.unstable;