Reporting the Connection Protocol Used by Outlook Mobile Clients

Knowing How an Outlook Mobile Device Connects

In my article about the new architecture Microsoft is deploying to connect Outlook for iOS and Android devices to Exchange Online, I mention a Microsoft FAQ on the topic. That FAQ includes some PowerShell code to help administrators know what protocol devices use to connect. The code is perfectly good, but being PowerShell, there are many ways to approach a problem and some to improve the solution. Here’s my attempt to do so.

The single-line command (always good) in the FAQ uses the Get-MobileDevice cmdlet to retrieve a list of devices that have connected to Exchange Online, extracts the devices running the iOS or Android client, and reports the protocol each device uses. All good, but the data would be more valuable if you knew who used the devices as well.

Mailboxes, Not Devices

My solution takes a user-centric approach to the question. The first step to know who is using Outlook for iOS or Android to connect to Exchange Online is to create a set of user mailboxes as they’re the only Exchange objects that can have mobile devices.

Next, we go through the list of mailboxes and use the Get-MobileDeviceStatistics cmdlet to examine details of mobile devices that have “partnerships” with each mailbox. We’re only interested in devices that report running Outlook for iOS or Android. If we find such a device, we grab the statistics like the O/S version running on the device and the date and time of the last successful synchronization. To know what architecture the device uses, we examine the ClientType property, which is “REST” if the device connects using the old architecture, or “Outlook” for the new.

Examining the Data

To see what data our code generates, we examine the $Report variable.

At the time of writing, clients in my tenant still use the REST protocol that’s soon to be replaced by the Outlook protocol. See the article for details.

Of course, if we need to do some deeper analysis, we can output the information to a CSV file with another command. The CSV file can then be loaded into Excel or Power BI to slice and dice the data, generate graphs, and so on.


For more information about Office 365 clients, read Chapter 10 of the Office 365 for IT Pros eBook, while Chapter 18 covers mobile devices.


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