Getting properties from Appointments not exposed in the API

Question

Is it possible to retrieve properties not exposed by the office.js API for appointment items in the OWA in a HTML Add-In (e.g. Milage) hosted on an Exchange 2013 Server (otherwise I could use EWS from the offíce js, i think in ex2016) ?

Answer 1

No. We are not able to get the properties which not exposed by the Office API. But we can use EWS from the mail app directly by makeEwsRequestAsync.

And we can use GetItem operation to get the specified properties and contents of items from the Exchange store.

Here is the document reference for Call web services from an Outlook add-in.