I'm currently working on an office VSTO add-in, and one the requirements for the add-in is that it should place a custom button on the starting tab of the backstage. The overall goal is to make a user see that custom button as soon as he opens an office application.
The challenging part is that this should work for all versions of Office starting in Office 2016, and the starting tab the user sees when he opens an app changes from between Office versions.
So far, I've been trying to use the productReleaseId to identify the starting tab and load a custom Backstage UI accordingly. However, I haven't had much success with that approach as it seems that even product with the same productReleaseId might have different starting backstage tabs.
Any idea on how I can make a custom button appear on the starting tab independently of the office version used?