Dom0 update fails

[unman]

You can free up space from logs:

journalctl --vacuum-time=1d

If you want to increase the size of dom0 to avoid this happening in the
future, you can also increase the space allocated to dom0. For example:

sudo lvresize --size 40G /dev/qubes_dom0/root
sudo resize2fs /dev/mapper/qubes_dom0-root

I never presume to speak for the Qubes team. When I comment in the Forum I speak for myself.