You could flag it, ask if they want it updated and then proceed to update if they said yes. A no would be a install halt and they'd have to manually update it if they wanted to move forward.
You guys stopped supporting the older linux that didnt support systemd..same would be for supporting the boxes on the grsec kernel. I think this pops up enough to warrant that. You guys cant keep trying to fix these on a one-off basis which seems kind of you but a lot to keep on doing going forward.