Comment 2 for bug 1721843

A possible solution is to remove the decorator from send_instance_update_notification() as the called _send_versioned_instance_update() already has the decorator. This way the legacy notification is still emitted from send_instance_update_notification in every case.

This also shows the lack of our legacy notification test coverage. But I guess it is not something to want to improve now as we are focusing more on the versioned notifications.