[rgoulter]

> The point is entirely different: if you update the channel-list you need the network for any changes to the configuration and I don't know of a way to go back to an earlier channel state.

`nix-channel` does have a `--rollback` flag to it.

However, I feel that Nix Flakes would allow you a better experience. With nix flakes, the revision of the nixpkgs input is persisted in a lockfile. You could check this file in somewhere, and then getting your working directory back to a known working state is much easier.