It is possible to set up each push notification among the following targets :

1. You can send notifications to all or specific groups or all the participants.
2. You can select participants one by one.
3. You can send the notification to all attendees registered to one session at least or multiple sessions.
Thing to know : participants who registered to a session will automatically receive a notifications 10 minutes before the session begins.
See also: Which notifications are activated by default?
4. You can send notifications to all your exhibitors by selecting the groups "Exhibitors."
5. You can send notifications to selected exhibitors only.