BubbleUPNP losing settings on kernel update

Hi,

Maybe someone here can either answer this question or point me in the right direction. I've been running BubbleUPNP Server on an intel NUC for some years. It can be used to create an OpenHome / DLNA renderer on the network for a ChromeCast device. (So you will have both a ChromeCast and an OpenHome/DLNA renderer for that device on the network.)

This is working fine, except for one minor annoyance. When I upgrade the Linux-kernel of the NUC and then reboot, BubbleUPNP loses all of its settings. I have to re-create all the OpenHome/DLNA renderers (6 renderers => 4 speakers and 2 groups) and redo all their settings.

I have not been able to find where BubbleUPNP stores its settings. There's nothing in the Home-folder or ~/.config or ~/.local as far as I can see. BubbleUPNP is installed in /opt, but the settings aren't there either.

It does have to save settings however, because on all other updates and / or reboots (when necessary) it just comes up and everything is as it should be. It only loses settings on kernel-upgrades, which makes me think it saves its settings in some non-standard place (/tmp? /var?) which is wiped when the kernel is upgraded.

Does anybody have any idea?