Session Capacity

Sessions can now optionally have a 'capacity' added to them. By default the value is not set, meaning that any amount of people can add the session to their personal agenda and any amount of people can be added via managed schedules. If this value is set then it will be enforced when people try to favourite the session for personal agendas, and when people are added via managed schedules in the CMS. This can help to make sure the session is not over-subscribed via any method. The session should display the remaining places when viewed in the app.