Returns a list of devices (device ref) that have changed since the last call to this function. The ID is used to isolate the list of devices in the case other systems are making this call. The ID should be the same for all calls from a specific system. The ID is typically a GUID.
This call is typically used for UI apps that poll HomeSeer for updates and want to update only the devices that have changed. Getting the status for all devices can by time consuming and resource intensive.