# become root
su -

# update to the last version of guix that works
# with older daemons
guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/afd532337.tar.gz

# update root's profile to get a new "guix" package
# including a new daemon
guix package -u

# edit the systemd unit to use the new daemon
sed -i "s|ExecStart=.*|ExecStart=/root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild" /etc/systemd/system/guix-daemon.service

# reload the unit file
systemctl daemon-reload

# restart the daemon
systemctl restart guix-daemon

# now become a regular user and run "guix pull"
exit
guix pull