Once the apps reach end of support later this year, Microsoft warns that users who haven’t moved to the new Outlook app “will no longer be able to send and receive email using Windows Mail and Calendar.

Microsoft is ending support for its Mail and Calendar apps for Windows 11, as it moves to make the new online and free Outlook its only mail option.

It's time to ditch your Windows Mail, Calendar, and People apps if you use them. Microsoft is no longer supporting the Mail, Calendar, and People apps on Windows 11. Collectively, these apps offer functionalities found in the more streamlined,

Windows 11's Default apps section within Settings might be getting an overhaul soon. Here's how it could look.

According to Windows Latest, you can either choose to open the new Outlook when booting Mail & Calendar, or reject it with a "not now" prompt, but the new Outlook will still open regardless of the next boot. You can also downgrade the apps to prevent this from happening, but these will also stop working on December 31.

If you're still using either of these apps, you'll need to switch to the new Outlook or find alternatives soon.

Microsoft will discontinue the built-in Mail and Calendar apps in Windows 11 after December 31, 2024, urging users to switch to the web-based Outlook app instead.