Nix-channel: unstable behind release-18.03?

I have been running NixOS on the unstable channel for a couple of months now.

These days, I was puzzled to discover that my Firefox was still running on version 59, even though Firefox 60 was long released and even already showing up on NixOS Search - Loading....

Now I found out that in fact the unstable-aarch64 branch indeed still has Firefox 59

…, whereas release-18.03 is already on Firefox 60:

Is this a general problem with the unstable channel or just a specific one with the firefox package?

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The channels are branches in another repository, named nixpkgs-channels.

nixpkgs-unstable has firefox at nixpkgs-channels/packages.nix at nixpkgs-unstable · NixOS/nixpkgs-channels · GitHub and it’s version 60.

What does your sudo nix-channel --list say? And did you ever run sudo nix-channel --update?

Also, unstable-aarch64 is no channel, just a branch in nixpkgs repository. They’re not run by hydra, afaik. See also the list at

I’ve noticed the same with nixos-unstable. These two issues mention being blockers for recent evaluations, though whether there are others too I can’t say:

Fingers crossed! Particularly as Firefox 60.0.2 is noted in PRs as the fix version for a CVE.

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Before, it was saying this:


Now I have this:


To be honest, I was always running nixos-rebuild --upgrade build (which I expected to update the channel) and then nixos-rebuild boot (if there were no warnings).

Thanks for the clarification, I must have mixed up those two repos.

I just verified that nixos-unstable has an older git-revision than nixos-18.03:

BTW, nixos-unstable not really “behind” 18.03, as it also contains lots of changes that are newer than 18.03. For checking recent history of channel updates you can also use It occasionally happens that unstable is stuck for a week or two; that’s less common for the stable branch(es), as there are fewer and less intrusive changes.

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It’s advanced today! openzwave: disable format hardening · NixOS/nixpkgs-channels@4b649a9 · GitHub

Is there a way that I could for instance pick a commit from master and local checkout
nixpkgs and use that as a channel? And still have binary cache and stuff.

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You can make any nix command use a local nixpkgs by passing -I nixpkgs=path/to/your/checkout or putting nixpkgs=path/to/your/checkout in the NIX_PATH environment variable for the command. Binary caches will be used according to availability, i.e. everything that has been built successfully by hydra will be downloaded from the binary cache rather than built locally.