Microsoft was long rumored to be working on a unified Outlook Mail and Calendar platform. A singular backend that was easier to develop, maintain, and troubleshoot. Although delayed, the “One Outlook” platform, also codenamed “Project Monarch”, is still under development, and could arrive later this year as an Optional Update for Windows. However, it would also be cross platform, arriving on macOS, iOS, and Android as well.
Microsoft Outlook is one of the oldest and most widely used email clients. However, it is also one of the most fragmented. Microsoft currently maintains multiple different versions of Outlook. There’s one for Windows, another for Mac, iOS, and Android devices. Then there’s MS Outlook for the Web.
Project Monarch was rumored to arrive as One Outlook last year. Just like every other major project, this one too got delayed, presumably due to the pandemic. According to Mary Jo Foley over at ZDNet, the One Outlook project will be christened as Outlook. The One Outlook project should eliminate the confusion in the front as well as the backend.
Windows 10 and Windows 11 already have a native Mail and Calendar app. It appears Microsoft is planning to gradually release the unified version of Outlook in the second half of 2022, presumably as a part of the 22H2 Cumulative Feature Update. It could appear as an Optional Update at first. Although there’s no official confirmation, it is quite likely that Microsoft could eventually replace the existing Mail and Calendar app with the new One Outlook platform.
The One Outlook platform should work identically on the Windows Desktop (Win32/UWP; Intel and ARM), on the Web, the macOS Desktop, as well as Android. And the only way to achieve this level of uniformity would be to model the new One Outlook on the current Outlook for the Web iteration. This would mean Microsoft could develop and deploy server-side updates, allowing quick access to users.