@Valer Thanks for the report and the writeup, that’s a good catch. You’re right about the cause. Debian 13 dropped the sysv-rc-conf package since it’s fully on systemd now, so the installer chokes trying to apt-get it. We never actually use that tool on a systemd system anyway, it only ever got called on the old non-systemd paths, so it was just dead weight on Trixie.
I pushed a fix to working-1.6. It leaves the package off the list on Debian 13 and up, and it also strips it out of a cached .fogsettings so an in-place upgrade doesn’t drag it back in. Older Debian keeps installing it like before so nothing changes there.
If you want to get moving before you pull the update, you can either grab the latest working-1.6 and rerun the installer, or just open /opt/fog/.fogsettings and delete sysv-rc-conf from the packages line, then run the installer again. Either one gets you past it.
Let me know if you hit anything else on Trixie.