My first NixOS Upgrade
NixOS 25.11 was released recently. So it was time to see how easy an upgrade for my NAS would be.
There are official upgrade instructions but I also found this reddit comment which gave a bit more advice.
So here is what I did. First I updated the channel:
# nix-channel --list nixos https://nixos.org/channels/nixos-25.05 # nix-channel --add https://nixos.org/channels/nixos-25.11 nixos # nix-channel --list nixos https://nixos.org/channels/nixos-25.11 # nix-channel --update unpacking 1 channels...
Next the reddit post recommends reading through the changelog and updating the nixos config.
In my case the Postfix config changed. nixos-rebuild will complain about some settings, but not all. I fiddled with the settings until it no longer complained, then rebuild and rebooted:
# nixos-rebuild boot --upgrade # reboot
The machine came up again correctly. But my postfix daemon wasn't working correctly. It took a bit more fiddling until I finally fixed it.
The whole upgrade took me about half an hour. Not too bad, but I am glad I am running most of my services via Docker compose, isolating them from the OS.