Microsoft 365: First Windows Mail and Calendar users will be migrated to the new Outlook at the end of August 2023

[English]Microsoft plans to gradually migrate first users of Windows apps Mail and Calandard to the new Outlook app starting in late August 2023. I'm not sure how excited users are about this.


1st announcement in June 2023

I had't mentioned it here in my blog, but reported on the announcement here. Joao Ferreira reports on Microsoft's plans to replace the Windows Mail and Calendar apps with the new Outlook for Windows. The article says that the switch should happen starting in September 2024.

Until that date, users should notice little of this move, but may receive a notice (mail tip) in the Mail and Calendar app informing them of the change. After the changeover, the following should apply:

  • Users can no longer use or download the Mail and Calendar apps from Windows.
  • Users with a Microsoft 365 or Office 365 subscription with access to the Microsoft 365 desktop apps can use the new Outlook for Windows.
  • Users without such a subscription can also use the new Outlook for Windows with any personal email account (, Gmail, etc.) without a subscription.

Microsoft published a post Outlook for Windows: The Future of Mail, Calendar and People on Windows 11 hat vaguely described these plans for "2024" and indicated that new Windows 11 installations would ship with the new Outlook as an app as early as 2024. But it said there that on existing systems, Windows Mail and Calendar (as well as the People app) would still be available until the end of 2024. So there would still be a year to go.

Migration to new Outlook starts end of August 2024

If I have noticed it correctly, it has then hailed user protests and Microsoft has made a backdown (see also this article). However, the article also points to where Rabia Noureen pulled text from the M365 changelog MC650424 titled Windows Mail and Calendar are becoming Outlook as of July 20, 2023.

MC650424 – The Mail and Calendar apps for Windows are being replaced with the new Outlook for Windows. At the end of 2024 Microsoft will be ending support for the Mail and Calendar apps for Windows. The new Outlook for Windows helps people be more productive and in control of their inbox. Microsoft is excited about this change that will provide users with great new productivity features such as Microsoft Loop, message reminders, as well as file and people suggestions while composing an email. The new Outlook also offers more ways to stay in control with drag and drop emails as tasks, work hours and location, pinning and snoozing messages and many others.


Important: In late August of 2023, Microsoft will also begin a process of auto-migrating Mail & Calendar app users to the new Outlook for Windows with an option to go back if they choose. Users can go back to the current Mail and Calendar apps by clicking the toggle in the new Outlook for Windows.

So also there the confirmation that the support for Windows Mail and Calendar will expire at the end of 2024. What is new, however, is the information that individual users will be switched from Windows Mail and Calendar to the new Outlook app as early as the end of August 2023.


Microsoft advertises to administrators that the new Outlook for Windows offers a higher level of control compared to Mail and Calendar. This includes, for example, the ability to adhere to conditional access policies, enable/disable integration of features like Dropbox, Linkedin, Google Drive, etc., enable/disable specific folders in Outlook, etc.

Outlook Schalter für Layout

Users within a tenant who have accounts logged into the Mail and Calendar app will get to see a Try the new Outlook option in the upper right corner in the app. This button will allow users to switch to the new Outlook for Windows.

In the coming weeks, users of the Mail and Calendar apps will see additional notices about the end of support in 2024, and will be told that they will then have to switch to the new Outlook for Windows.

Concerning the topic of "new Outlook", I would like to remind you of my post Microsoft is installing Outlook-Preview without permission. This already picked up on this option in mid-April 2023 and mentioned that this change may cause increased training efforts for Outlook users in companies.

In addition, in mid-May 2023, there was the blog post Microsoft is installing Outlook-Preview without permission, where first users (presumably in a test) were switched to the new Outlook (which is still in the preview phase). The users wasn't happy at all. So administrators, if the issue is not yet on their radar, should prepare for this changeover – even if Microsoft writes that you don't have to do it.

Addenum: I just read at Windows Latest, that Windows 11 users protests as Microsoft plans to force Outlook web app, replace UWP. Seems not a well appreciated move from Microsoft.


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