M365 Customers Can Keep Classic Outlook Until at Least 2029

• Customers have at least two years before new Outlook replaces classic Outlook in the Microsoft 365 Apps for enterprise suite.
• Enterprises can stay on classic Outlook until at least 2029 by downloading and deploying Outlook separately from the suite.
• Moving from classic to new Outlook will disrupt business processes if customers have not prepared.

Apr. 12, 2025: The report has been updated with status of new Outlook features and plans to support Exchange Server through IMAP.

Customers who license the Microsoft 365 Apps for enterprise Office suite will be switched to a radically different “new Outlook” sometime in the next few years. However, organizations will be able to keep using “classic” Outlook until at least 2029, as long as they are willing to download and deploy the app separately. New Outlook still lacks features and drops some much-used development technologies from the current classic Outlook on Windows, so the change could break business processes and confuse some users as well. Customers licensing Office in Microsoft 365 plans should get ahead of the change and understand their options.