Updating channel 'guix' from Git repository at 'https://git.guix.gnu.org/guix.git'...
Building from this channel:
  guix      https://git.guix.gnu.org/guix.git	12197aa
Computing Guix derivation for 'x86_64-linux'... |warning: 'abjad' is deprecated, use 'python-abjad' instead
warning: 'abjad' is deprecated, use 'python-abjad' instead
|
nothing to be done

hint: After setting `PATH', run `hash guix' to make sure your shell refers to
`/root/.config/guix/current/bin/guix'.

guix system: warning: Consider running 'guix pull' before 'reconfigure'.
guix system: warning: Failing to do that may downgrade your system!
guix system: error: aborting reconfiguration because commit 21ce6b392ace4c4d22543abc41bd7c22596cd6d2 of channel 'guix' is not a descendant of a9fb5fa2b9e9f36f8d6f601966d775fe4fe9a47b
hint: Use `--allow-downgrades' to force this downgrade.