When a new event is created or an existing event is edited, notifications are sent to all subscribers of a public calendar automatically.
For Public Calendars
When changes have been made within a public calendar, subscribers of the public calendar will receive messages in their inbox as well as a red circle on the public calendar icon within the app.
For Public Events
When changes have been made to a public event's description, date and time or location, people who have added the event to their calendars will have the event updated automatically within their shared/personal calendars.