If you want to stay up to date with a set of packages, it’s not very convenient to manually download the latest set of Nix expressions for those packages, use nix-pull to register pre-built binaries (if available), and upgrade using nix-env. Fortunately, there’s a better way: Nix channels. A Nix channel is just a URL that points to a place that contains a set of Nix expressions and a manifest. Using the command nix-channel you can automatically stay up to date with whatever is available at that URL. You can “subscribe” to a channel using nix-channel --add, e.g., $ nix-channel --add http://nixos.org/channels/nixpkgs-unstable subscribes you to a channel that always contains that latest version of the Nix Packages collection. (Instead of nixpkgs-unstable you could also subscribe to nixpkgs-stable, which should have a higher level of stability, but right now is just outdated.) Subscribing really just means that the URL is added to the file ~/.nix-channels. Right now there is no command to “unsubscribe”; you should just edit that file manually and delete the offending URL. To obtain the latest Nix expressions available in a channel, do $ nix-channel --update This downloads the Nix expressions in every channel (downloaded from url/nixexprs.tar.bz2) and registers any available pre-built binaries in every channel (by nix-pulling url/MANIFEST). It also makes the union of each channel’s Nix expressions the default for nix-env operations. Consequently, you can then say $ nix-env -u '*' to upgrade all packages in your profile to the latest versions available in the subscribed channels.