Microsoft has simplified the synchronization architecture used to connect Outlook mobile clients to Exchange. The new approach sets the scene for some new functionality, like support for S/MIME and access to shared mailboxes. It's all good and it marks the continued progress of Outlook mobile since the Acompli acquisition in 2014. https://www.petri.com/outlook-mobile-gets-new-architecture
Microsoft has refreshed the Outlook Mobile architecture. They suggest that you run some PowerShell to report clients connecting via the old and new architectures. Their code works, but we think ours is better.