Microsoft’s new web-based Outlook for Windows is set to replace the Mail, Calendar, and People inbox apps on Windows 11 in September 2024. Microsoft announced the change on its Microsoft 365 Admin Center yesterday, and more details about the transition can also be found on a support page.

“Beginning in 2024, new Windows 11 devices will be shipped with the new Outlook for Windows as the default mailbox application free for all to use,” Microsoft explained. The existing Mail and Calendar apps will soon display a message inviting users to try the new Outlook for Windows using a slider.

Microsoft’s new web-based Outlook for Windows app has been available in beta for quite some time, and the company had already announced that it would eventually replace its UWP-based Mail and Calendar apps. What was still missing was the timeline. On the Microsoft 365 Admin Center, Microsoft explained that users will no longer be able to use or download its Mail and Calendar apps after September 2024.

If you already use Outlook on the web (or Outlook.com for consumers), you’ll be in very familiar territory with the new Outlook for Windows. The new client does support multiple accounts, though it currently lacks the ability to create unified inboxes, which was probably the Mail app’s real killer feature.

While some Windows 11 users may likely miss the built-in Mail and Calendar apps when they eventually stop working next year, Microsoft making a new version of Outlook for Windows available for free on Windows 11 is quite a big deal. On a support page, Microsoft emphasized how users “will write better emails with advanced AI built into the new Outlook for Windows to help you write impactful, clearer, mistake-free messages.”

Microsoft will continue to support its classic Outlook for Windows desktop app, which requires a paid Office license or a Microsoft 365 subscription. The legacy app still has many features that power users rely on, so it’s likely not going away anytime soon.