I’m new to NixOS. Do I have to do anything extra to update NixOS? Or do I just update my flake and run nixos-rebuild switch --flake like I normally do to update packages?
What if I just want to upgrade some packages? Like not change channel, but Firefox needs an update? I’m not op and don’t use flakes btw
If using flakes you could just for instance add another input. You can also set the input URLs to specific states of the nixpkgs repository by eg referencing specific commits. Then, you should be able to just, e.g., pick Firefox from unstable, another package from the current stable channel, and maybe a broken package from a pull request fixing said package.
If you are not using flakes you can also add system wide channels. IIRC you can then import these channels into your configuration.nix and select packages from the corresponding channels. But here the channels/inputs are not part of configuration itself in contrast to when using flakes.