This feature might not be much to write home about, but still, it proves that the Notes Mail is evolving and continuously improving the user experience.
Typically when receiving invites to meetings, the invitations would not appear in the calendar, before it had been accepted and it could only be found and processed from the inbox. This has been changed with ghosted invites, which present the opportunity of showing new invites in the calendar, ghosted, with colors of your choosing. This
A very nice feature added to the Calender in 8.5 is the Calendar Overlay which makes it possible for you to add external calendars entries to your Notes Calendar. This feature supports the following calendar types