For several months now Microsoft has been giving users of the Web version of Outlook an option to preview their next version by turning on “The new Outlook” in the top-right corner of the interface. Microsoft is now rolling out this updated user interface to all users. It will no longer be optional and all users will be switched automatically to the new Outlook. Use this link to get more information about the new Outlook on the Web: https://techcommunity.microsoft.com/t5/Outlook-Blog/Faster-with-a-modern-design-and-new-features-the-new-Outlook-on/ba-p/735222