This issue remains present when going from 12.12 -> 13.1. Recap:
There is an order-of-operations issue when going from Debian 12 to Debian 13, where systemd has to be updated before mdadm. Not doing so triggers the error message about systemd missing. Minimal reproduction: * Prep system for bookworm->trixie upgrade as per release notes * sudo apt update && sudo apt install mdadm This will bring up the error screen about systemd being the only supported init system. I wanted to see how it behaved outside of full-upgrade so I had a smaller reproduction. Next I wanted to see whether this has anything to do with the order of upgrades. * Prep system for bookworm->trixie upgrade as per release notes * sudo apt update && sudo apt install systemd * sudo apt update && sudo apt install mdadm This does not cause the warning. Current conclusion: When mdadm is updated before systemd during apt full-upgrade, this causes a warning that the systemd init system cannot be found. A workaround can be to hold mdadm, run the full-upgrade, unhold mdadm, and run full-upgrade again. Alternatively, running an apt install systemd, then running full-upgrade, will also succeed. How to handle that is something you understand 100x better than I do. Systemd becomes a dependency so it’s always updated before mdadm? Trixie mdadm handles an older systemd as encountered during upgrade gracefully? Yours Thorsten Please see the important legal disclaimer at https://www.galaxy.com/email-disclaimer which must be read and considered in connection with the information in and attached to this email.

