Many users ask the following question:
"I create an event in Attendance Tracker, and add participants to the event from the contacts on my device. If I update a device contact (change name or picture) will the participant in Attendance Tracker also get updated?"
Yes, Attendance Tracker is fully synced with your Android contacts: when you create a participant to an event using a device contact, the participant is kept in sync with the device contact.
Changes to the name or picture of the contact automatically appear in Attendance Tracker.
When you delete the contact from the device, Attendance Tracker transforms the participant in the event to become "app local". The sync is stopped, but you will still have the contact (and any associated historical data in Attendance Tracker). You can also re-link an app local contact to a Android contact again using the context menu in the event setup page.