Option in setting to pick syncing App with iPhone Calendar both ways, or App-to-iPhone Calendar only, or the other way around—my wife and I share the same iPhone Calendar so we know each other's schedule, she does not like me putting everything into the Calendar; it is nice to have the option to sync iPhone Calendar items to the App, but not my clustered items from the App to iPhone Calendar; if I have items to share, I can put it straight into the iPhone Calendar