How to set Importance to High in Outlook javascript add-in?

Question

I have an Outlook Javascript add-in that is used to generate a message.

Currently I am stuck with how to set an Importance to High using Office.js api.

There is a specification https://www.rfc-editor.org/rfc/rfc4021#page-32 that says to use a header in this case. So I tried to use Internet Headers ( https://docs.microsoft.com/en-us/javascript/api/outlook/office.internetheaders?view=outlook-js-1.8 ), but apparently this API is created for custom headers, not the default ones. And I can't find another suitable API as well.

So is it possible at all? Anyone succeeded?

Thanks in advance

Answer 1

This is currently not possible with the Office.js APIs. We track Outlook add-in feature requests on our user-voice page. Please add your request there. Feature requests on user-voice are considered, when we go through our planning process.

https://officespdev.uservoice.com/forums/224641-general/category/131778-outlook-add-ins

Answer 2

What existing API are you using to "generate a message"?

I have no problem in my Outlook add-in using EWS with this:-

<t:Importance>High</t:Importance>

(Using the Office.context.mailbox.makeEwsRequestAsync(xmlmail, ...) API)