Yes, connactz synchronizes seamlessly with Google Calendar, Outlook and Apple Calendar. You can display your external calendars directly in connactz and, conversely, subscribe to the connactz calendar in your existing tools via a private iCal feed. You set up both from your avatar menu under Integrations - see Connect calendar. The subscription is read-only; when changes appear there depends on your calendar app's fetching schedule, so not necessarily immediately. If appointments are missing, Calendar synchronization: appointments are missing or do not update will help.