I have a system running for ~80 days without any update. When I try to update it with nixos-rebuild --upgrade boot the configuration is built but no new paths are copied from the nix store. Installing new software works fine without errors. I’m on 19.09.2520.289466dd6a1 (Loris).
What’s going on here?
If you check https://status.nixos.org/ you can see that 19.09.2520.289466dd6a1 is indeed the latest version of NixOS 19.09 (check the commit hash). According to the release notes support for 19.09 ended April 2020. The best thing to do is probably going just upgrading to 20.03 ASAP.
Someone more familar with the releases might know more about the ‘mysterious’ update 2 months ago.
Doh. That was too simple. I better gonna build myself something which notifies me about the EOL of the current release…