I'm developing an integration with Outlook in Office 365 using the latest office.js api for add-ins.
What I have currently is an add-in, which displays a side pane on the appointment compose form. Inside that pane I have the functionality to create an object in our external based on the appointment, taking the start/end times, subject, location etc.
So I have appointment A in the calendar of an O365 account, and object A in an external system.
Is there a way to keep those in sync? I don't see it could be possible using the Outlook Add-In Javascript API, but maybe using ics files, or the Outlook REST API, or Exchange EWS? I see here plenty of issues with the credentials, as the user has separate credentials in our system.
Any tips? I tried to send from our system an ICS file with same iCal UID, but Outlook ignores it.