downgrade issue on guix system

[Alexander Asteroth]

Dear all,

I just wanted to install cups service on my guix system. I recofigured
the system without an error one hour ago (introduced seperate home
filesystem) and now, when I try to add the cups service (I did a guix
pull in between as well) I get:

> guix system: error: aborting reconfiguration because commit 
> bd2aa8031babdca5f574fca52e025d6794f08d82 of channel 'guix' is not a 
> descendant of 7f974548ac20cab88b9bb589a5e1d85ee3b8d337
> hint: Use `--allow-downgrades' to force this downgrade.

I have no clue what caused that error therefor I also don't know if it's
a good idea to allow downgrades. ... or what es to do to resolve the
issue.

Cheers,

Alex