In Loco Engage depends on two processes in order to deliver push notifications through the UA platform: registration and message sending.
The registration step serves to create an endpoint between the Engage backend and your user's device, so Engage can send push notifications to the device through Urban Airship. This endpoint is represented by a Channel ID, generated and refreshed by Urban Airship. This step will guarantee that Engage always has the latest Channel ID.
The registration step takes place when the app opens. The Urban Airship SDK registers itself with the Urban Airship backend, thus generating a Channel ID. This Channel ID should be passed to the Engage SDK, which updates the Engage Backend.
The step above is repeated every time a Channel ID is refreshed by UA.
The message sending step includes the visit detection, visit processing and sending the push notification. The Engage SDK detects that a user is visiting a point of interest and communicates the Engage API. The Engage API then enhances the location information and checks if the push notification should be sent. Then the Engage API, using the Channel ID, publishes notifications via Urban Airship and the message is delivered to the user.