I need to en-masse change the membership of devices from their many pre-stages into one. All of these devices are in a single smart group. I’ve downloaded MUT, but this doesn’t seem to be able to do what I need to achieve, unless you know the existing pre-stage ID, (unless I’ve got that wrong!)
I guess that i could download all the serials from the smart group, remove them via DEP and then assign them back to the new pre-stage, but that seems clunky to me.
Has anyone managed to script this using the API?
Are you going to erase all of the devices after changing the prestage? That's the only way the smart groups would be updated (if the group is based on enrollment method). Changing the PreStage doesn't change how existing devices were enrolled in the past.
If the issue is determining the JSS ID for the different PreStage enrollments, just look at the URL in your browser. The URL will contain something like this: "mobileDevicePrestage.html?id=5" (where 5 is the ID). For MUT you also don't need to know the old ID, just the ID of the new PreStage where the devices will end up.
You figured out the way that I always do it. Whenever I need to bulk change prestages, I go the ASM/ABM route and just unassign the devices from our MDM, wait a few minutes, and then assign them all back.
It is a little clunky, but I have never run into any issues taking this route.