After you sync your calendar, you can click on the Calendar Sync button to determine the last sync date and timestamp of the last request received from your personal calendar; see the current filters applied to this view; and an option to update your synced filters or add another external calendar.
If the Last Sync Date timestamp is older than 48 hours, it means that your personal calendar may be not up to date. To ensure that you have the most current information in your Calendar View, you should re-sync your personal calendar to ensure the event updates keep flowing (by repeating the sync set-up steps).
To update your filters and add new project events to your calendar, click on the Filters button (next to the Calendar View in the top menu tabs). The Filter menu will appear (as below). You can then select a new set of events.
Once finished, click on the Sync Settings button at the right, and then click on the Update button.
A message will appear (as above), confirming that you wish to replace your existing filters with the new ones you just selected. After you click Update, the current synced filters will be replaced by the newly applied filters and new events matching those criteria will be automatically added to your calendar during the next sync.