I recommend you do not reconfigure any systems that are important based
on the current core-updates branch.

After applying the proposed fix for GPM [0], I reconfigured my headless
GuixSD system using core-updates.

After rebooting, I found that my user's numerical ID had changed, so I
no longer owned any of my files. Not being able to read ~/.ssh means you
can't log in remotely.

Additionally, several of root's "dotfiles" had been replaced with their
default versions, erasing my modifications. For example,
~root/.bash_profile no longer contained my modifications.

Finally, my users's password no longer worked. I fixed this as root
before I noticed that my user's files were inaccessible; I don't know if
I could have avoided the password reset by re-chowning my files.

[0] <https://bugs.gnu.org/29975>