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Updated February 20, 2026: We have updatedWe're making some changes to the timeline. Thank you for your patience.
Introduction
Microsoft is updating the opt‑out phase start date formigration from classic Outlook to new Outlook for Windows.
We aim to give more than 12 months of notice to help our customers prepare. Starting April 2026, users with Microsoft 365 for Enterprise licenses will be toggled from classic Outlook for Windows to new Outlook for Windows. Users will be toggled into new Outlook once with this roll-out, with potential to be toggled again in Enterprise environments from April 2026the future. Users will maintain the ability to March 2027.go back to and use classic Outlook.
Our goal with this change is to give users an opportunity to try new Outlook as millions of users already have. New Outlook gives users the most modern experience with Copilot features, theming, and a wave of valuable time-saving features like Pinning and Snoozing mails. Users are also welcome to give us feedback on new Outlook using Feedback in the Help ribbon, so we can tailor the best email and calendar experience.
When this will happen:
General Availability (Worldwide): We will begin rolling out phase for April 2026.
How this will affect your organization:
You are receiving this message because our reporting indicates one or more users in your organization are using Microsoft 365 Enterprise environmentslicenses.
Users will now beginhave notice in March 2027 (previously April 2026), providing organizations with 12 monthsthe application prior to being toggled and will have the option to opt out of lead time to prepare.
Why is there a change to the timeline?
We’re seeing strong and accelerating adoption ofexperience in Outlook Options > General. Users who are toggled into new Outlook as organizations progress on timelines that match their readiness. At the same time, we continue to invest heavily in expanding capabilities and addressing feedback from customers who want to go further with new Outlook. To ensure organizations have the time they need to prepare—and to fully realize the value of ongoing innovation—we’re extending the opt-out timeline and providing 12 months of lead time as we continue delivering key features and improvements.
How this affects your organization:
Who is affected:
What will happen:
Users will not be migratedtoggled if one or more of the following is true:
User-facing article: Switch to new Outlook for Windows - Microsoft Support. We will continue to update this article as we get closer to April 2026.
What you canneed to do to prepare:
Prepare your organization for the opt-out phase thatThis rollout will begin March 2027. Evaluate and use the Admin-controlled migration policyhappen automatically with no admin action required starting April 2026. You may want to the stage and schedule that is right for your organization.
Take preparatory steps to:
Be sure to communicate withnotify your users about whatthis change and update any relevant documentation as appropriate. When this change takes effect, if you choose to expect, and leverage Microsoft’s adoption resources to makeexclude users from the experience smooth.
Resources and Support:
Microsoft is committed to helpingexperience, you manage this transition effectively. Refer tocan use the following resources for detailed guidance and tools:
Later, this policy will also be presented with a user-friendly onboarding experienceavailable via Group Policy Objects (GPO), Cloud Policy, and will have the option to switch back to classic Outlook. Microsoft recommends starting with new users in your organizations and those piloting and using Copilot as early target audiences. Policy for Admin-Controlled Migration to new Outlook for Windows | Microsoft Learn; User-facing article.
Compliance considerationsIntune.