I speculate that as the chips on the ID40 and ID41 are configured differently, the tasks shared between cards and main 861 boards may be different. This may mean it is a challenge to make them work in all combinations with the same firmware.

Making the ID41 a mandatory part of the upgrade isn't a disaster but it isn't the flexibility originally understood.

Am sure we'll get clarity on this topic over the coming days.

Rgds,
Nick