I have the app installed on my iphone, and I can send notifications to it from the associated presence sensor, but it never sends any events at all. If I use the hub interface to set the device to departed, then click "Send geo event" on the phone app, it updates correctly at the hub. It never spontaneously updates it's status though.
I had renamed the device, and someone in a previous thread had suggested creating a new presence sensor, so now I have a new presence sensor currently. The old one has the same behavior.