Microsoft is working on an all-new Outlook for Windows, based on the Outlook.com web app. Now there's a new personalization feature coming to both versions that takes inspiration from the now-abandoned Windows 10 Mail app.

The official Microsoft 365 Roadmap has been updated with a listing for a new feature in development for Outlook. It will allow the new Outlook Windows app and the Outlook web app to have a background image in the reading pane, adding a splash of personalization to your inbox. The feature is expected to start rolling out in June 2023.

Microsoft explains on the roadmap, "To offer more personalization to end users, Outlook on the web and the new Outlook for Windows will now have the ability to display a background image in the reading pane whenever emails are not selected. This feature will be turned off by default for commercial customers. A user will be able to turn on a background image by going to Settings General Appearance from Outlook."

There's no screenshot of the promised functionality yet, but it sounds exactly like what is already available in the Windows 10-era Mail app. The older Mail app has a color picker to change the primary accent color (or it could use your system's default accent color), and you can choose a background from the built-in library or any custom image. The background can appear in the sidebar and reading pane, and when you open an email, the background in the reading pane goes away so you can focus on the message.

The new Outlook app is supposed to replace both Mail for Windows and the legacy Outlook client when it's complete, so it makes sense that Microsoft is porting over a few features from the Mail app. The new Outlook is currently in public preview, with no confirmed timeline for a final rollout.

Source: Microsoft 365 Roadmap