Channels for 13.10, 14.04, 14.12 return 404 with a CloudFlare error page.
Go to https://nixos.org/channels/
Try to download the versions mentioned in the description.
n/a
cc @edolstra
To be clear, one needs really good reasons to use that much old channels. For now you can use branches from https://github.com/nixos/nixpkgs-channels – binaries themselves should be still obtainable from the cache automatically.
For the record @sevcsik tried the old channels to upgrade from 14.04 to unstable: https://botbot.me/freenode/nixos/2017-12-18/?msg=94772225
Yes, unfortunately RamNode ships a 14.04 ISO only, and this made it was a bit baffling to me as a newcomer why nix-channel --update didn't work, as it failed with a rather cryptic error.
Closing, by now those channels are _really_ outdated
Most helpful comment
For the record @sevcsik tried the old channels to upgrade from 14.04 to unstable: https://botbot.me/freenode/nixos/2017-12-18/?msg=94772225