Microsoft is beta testing the third redesign to Outlook.com during the products five-year life span. Changes include putting an emphasis on search, improving smart inbox features such as adding restaurant locations and rating when mentioned by name, attachment previews in the inbox, and animated GIFs.
https://www.notebookcheck.net/Outlook-com-beta-shows-a-redesigned-look-with-useful-new-features.240820.0.html