How Microsoft Deploys New Outlook Mobile Features

Deploying Technology to 100-plus Million Users

After the note about the launch of shared mailbox and dark mode support for Outlook mobile appeared, several people commented that they had the latest client but couldn’t access the shared mailbox feature. This prompted me to have a conversation with Microsoft to find out how they deploy new features to what is now a very large (100+ million as of May 2019) installed base.

Outlook Mobile has both consumer and commercial (Office 365) users. Some features, like dark mode, are available to both sets while others, like shared mailboxes, are only available to commercial customers. The deployment mechanism needs to take account of these factors.

Random Selection During Roll-Out

When Microsoft releases a new Outlook mobile feature, they select a random percentage of the worldwide installed base as the initial roll-out target. For features like dark mode intended for use by any Outlook mobile user, the random selection is formed of individual commercial and consumer users. Commercial-targeted features like shared mailboxes begin deployment to a random selection of Office 365 tenants. If the selection is user-based, selected users can access the new feature immediately while others in the same tenant must wait until the roll-out reaches them. If the select is tenant-based, everyone in the selected tenants can access the new feature once the tenant is enabled.

Eventually the roll-out reaches 100% and everyone who has the latest version of the Outlook mobile app (iOS or Android) can access the new feature. The exact timing from start to finish of a roll-out varies across features and depends on factors such as bug reports or problems detected in the telemetry Microsoft gathers from Outlook clients.

No Control for Office 365 Tenants

Office 365 tenant administrators can’t influence the selection of their tenant or users within their tenant to receive new Outlook mobile features early. There’s no equivalent of the Targeted Release capability that exists for Office 365 features. There’s also no way for a tenant administrator to know who in the tenant might have been randomly selected to receive early access to a new feature. One way of looking at this is to say that random selection is fair to everyone; another is to say that Microsoft should give tenants some control over how new client technology is deployed to their users. On balance, it seems to me that Microsoft should provide some way to control deployment of commercial features, perhaps as a setting available through the Office 365 Admin Center.

There’s also no way to disable one or more Outlook Mobile features on a selective user-by-user basis. This might be useful for commercial features where some tenants don’t want people to use certain capabilities (like shared mailboxes) on mobile devices.

Testflight Makes a Difference

Those who sign up for the Outlook Insiders program and use the Testflight version of Outlook for iOS are not restricted by the random selection process and can use new features as Microsoft deploys them to Testflight. This can lead to an interesting situation where a tenant account can access a new feature through Testflight while another account in the same tenant can’t when using the production version of Outlook for iOS.

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Need to know more about Outlook Mobile and other Office 365 clients? The Office 365 for IT Pros eBook covers this topic in some detail!