Detect template updates available?

[joev...@gmail.com]

In Qubes 4.0 (RC4)

How does Qube Manager (or previous Qubes Manager) detect when a template VM has an available update?

I understand that qubes-update-check.service is on the VMs that are running so it can report back to dom0 to let it know there is an update available for its template (or itself if standalone VM).

But on dom0, is there a file or flag that shows which VMs? How does the manager app know?
After the UpdateVM (qubes.InstallUpdatesGUI) is run successfully on the template, and it completes a shutdown... how is this flag cleared.


Thanks.


P.S.
I found /var/lib/qubes/qubes.xml and its "updates-available" feature tag. A couple of my templates are set to 1, but after an update, this doesn't change.

[joev...@gmail.com]

Looks like qvm-features reads from /var/lib/qubes/qubes.xml... and they both show, "updates-available" set to 1.

But it appears that this value doesn't get cleared after a qubes.InstallUpdatesGUI is run.