nixos-and-flakes-book/docs/nixos-with-flakes/update-the-system.md

Updating the System

With Flakes, updating the system is simple. Just run the following commands in /etc/nixos( or any other place where you keep the configuration.):

# Update flake.lock
nix flake update
# Apply the updates
sudo nixos-rebuild switch

Sometimes, you may encounter a sha256 mismatch error when running nixos-rebuild switch. This can be resolved by updating flake.lock through nix flake update.