Microsoft 365 Enterprise users will be automatically migrated to the new Outlook in April 2026

Microsoft has been adding a bunch of new features to the New Outlook for Windows app lately, including features that improve offline usability, something that Classic Outlook does much better. Basically, improving New Outlook is a top priority for the Redmond giant, as the company hopes to move all users to the new app platform as soon as possible.

In mid-July, Microsoft announced that the new Outlook email app for Windows would be available to commercial users on August 1. That timeline has arrived, and along with it, Microsoft also revealed that the new Outlook Windows app has reached the GA (general availability) level for businesses.

Today, more than four months after the new Outlook for Windows reached GA, Microsoft has officially announced the timeline for when commercial users of the Microsoft 365 Enterprise platform will automatically (mandatory) be migrated from Classic Outlook to New Outlook for Windows. The company said that businesses that move to the new Outlook for Windows will be able to receive more complete support from Microsoft, and of course, better performance and experience.

Microsoft also detailed the rollout process and stated that users will continue to have the option to revert to the old Outlook Classic experience:

“Starting in April 2026, Microsoft 365 for Enterprise users will be transitioned from classic Outlook for Windows to the new Outlook for Windows, with the option to revert if desired. This change is intended to improve the user experience with modern features. Organizations are notified to prepare, with automatic deployment that requires no admin action but allows for opt-out options.

Microsoft aims to provide more than 12 months of advance notice to help customers prepare. Starting in April 2026, users with Microsoft 365 for Enterprise licenses will be moved from classic Outlook for Windows to the new Outlook for Windows. Users will be moved to the new Outlook synchronously during this rollout, and of course will have the option to return to the classic Outlook experience.

The new One Outlook for Windows app will bring better integration with Microsoft Teams, along with a series of improvements to the Calendar widgets as well as the ability to automatically pin an important email to the top of the interface, etc. According to Microsoft's plan, the new Outlook will completely replace the current Outlook app.

In a customer survey conducted by third-party organization Forrester Consulting, results showed that users of the new Outlook Windows app expect to reduce support tickets by 65% ​​compared to using the "classic" Outlook Windows app. The survey also found that customers expect to cut both energy and storage costs by 27% when using the new Outlook Windows app.

System administrators will gradually receive emails about the conversion proposal.