app: 0.1.49 failed to start and showed an empty screen on every page. Anyone on 0.1.49 should upgrade; there is no workaround on that version and nothing about it was recoverable from the node itself.
Features
presence: You can define circular zones and the devices you want tracked against them, so presence becomes something the system knows about and can react to rather than something you wire up by hand.
presence: A phone can post its position in the background using a key issued per device, so it does not need to sign in, hold a session, or keep the app open. Standard location-feeder apps that use basic authentication work directly against it.