I don't think we should simply remove backup software from our repo. While people should certainly not do any new backups using obnam, there are probably still people relying on it for restoring their old ones. Therefore, I vote to revert this change. We might want to mark obnam as broken or insecure and provide a link to the announcement.

I don't think it's our responsibility to slowly phase out software after the upstream project has been officially dead for a year.

There are probably still people relying on it for restoring their old ones.

Nothing's really deleted from git. Anyone who really needs the package can just copy the expression locally and build it locally.

But feel free to revert if you disagree.

After updating my NixOS channel I have realised that it's time to find a new backup program. :-)

I think removing it from nixpkgs reflects the author's wishes because he asked for it to removed from the next release of Debian.

Lucky Nix users can run nix run -f channel:nixos-18.03 obnam, which should work for years to come.