We have been notified of the following by Microsoft and only affects Outlook for Mac users.
After October 2025, Microsoft 365 subscriptions associated with a Microsoft 365 account (personal, work, or school) will no longer be able to use legacy Microsoft Outlook for Mac. This transition marks a significant step towards a more robust, feature-rich, and secure email experience for all users.
The latest version of Outlook for Mac has been part of the Microsoft 365 suite for the last four years. More than 95% of Microsoft 365 users have already moved from legacy Outlook for Mac to the new version.
Users will no longer be able to switch back to legacy Outlook for Mac after this change is implemented.