- Notification subscriptions: https://msdn.microsoft.com/en-us/library/office/dn458790(v=exchg.150).aspx and https://msdn.microsoft.com/en-us/library/office/dn458791(v=exchg.150).aspx
- Password change for accounts: https://support.office.com/en-us/article/Change-password-in-Outlook-Web-App-50bb1309-6f53-4c24-8bfd-ed24ca9e872c
- Support HTML body content. See http://stackoverflow.com/questions/20982851/how-to-get-the-email-body-in-html-and-text-from-exchange-using-ews-in-c
- Build up validations on all EWSElement fields. See example in Item.clean()
- CalendarItem recurrences: ecederstrand#37