Microsoft's 'One Outlook' email client may arrive in preview this spring

Outlook Web App
Outlook Web App (Image credit: Windows Central)

What you need to know

  • One Outlook (Project Monarch) is almost ready for preview.
  • It could arrive as soon as this March.
  • This is Microsoft's (eventual) replacement for Mail & Calendar on Windows 11.

Last year, Windows Central reported that Microsoft was working on a new Outlook client, codenamed "Monarch" and based on Microsoft's Outlook Web experience. Originally, Microsoft expected to begin shipping the app in preview in the summer of 2021, and replace the Mail & Calendar apps on Windows 11 later this year. For whatever reason, that initial preview never arrived.

Now, a report from ZDNet's Mary-Jo Foley has shed some light on the whereabouts of Project Monarch, stating that the app is still in development and may arrive in preview as soon as this spring. Microsoft does still intend to replace the Mail & Calendar apps, though that may not happen this year. Instead, Microsoft will place the new Outlook client alongside the Mail & Calendar apps while users get used to the new experience.

Microsoft has been testing Monarch/One Outlook for several months internally with increasingly large rings of employees. My sources say the company is planning to make an official announcement about One Outlook this spring. Microsoft could be ready to get a test version of the new Outlook to Windows Insiders in the Dev and Beta channels by late March or early April 2022, my contacts say. By late July or August this year, Microsoft is hoping to be able to get it to Insiders in the Slow Channel, though this target date could slip until the fall, my contacts said.

Microsoft has been hard at work on its new One Outlook client for well over a year at this point. It's Microsoft's goal to consolidate and unify the Outlook app experiences on desktop with a single client that's powered by the web. Microsoft hopes that this new client will eventually replace Mail & Calendar as well as Outlook Win32, though that plan is much further out.

For now, we're getting close to the first preview release of One Outlook, which Foley states will roll out first to Insiders in the Dev and Beta Channels in late March or early April. It'll then make its way to the Insider Slow Channel sometime in the summer.

Zac Bowden
Senior Editor

Zac Bowden is a Senior Editor at Windows Central. Bringing you exclusive coverage into the world of Windows on PCs, tablets, phones, and more. Also an avid collector of rare Microsoft prototype devices! Keep in touch on Twitter and Threads