How to fetch email headers with Office 365 Mail REST APIs?

Question

I can't seem to find a way to fetch raw RFC 2822 email headers from the message resource https://msdn.microsoft.com/office/office365/APi/complex-types-for-mail-contacts-calendar#RESTAPIResourcesMessage

All the standard headers To, From, Subject are available. How do I get a list of headers[] other than the standard once such as "Received", "Delivered-To", etc.. Is this feature not yet supported?

Answer 1

Igor - Office 365 REST API doesn't currently support returning the RFC 2822 email headers. This is on our roadmap to add, but we don't have a firm timeline yet.