A dynamic group membership rule can be added with “devices.status equal 0”.
This would be very useful for e.g. Maps -> Device Group Dependencies
However, the device group membership is updated by the poller, and the poller code won’t update the device group membership for devices that are down :
includes/polling/functions.inc.php
if ($response['status'] == '1') {
// Update device_groups
I’d very much like to see the “Update device_groups” code to be run even for devices that are down.