Since the major release of Microsoft Launcher 5.0 towards the end of last year, Microsoft has been pushing out a relatively steady stream of incremental updates to its home screen replacement for Android. Many of the updates seem to be pretty minor, and that seems to be the case with the new release heading to beta testers right now.
Microsoft is rolling out version 5.8 of Microsoft Launcher to those who have enrolled in the beta program through the Google Play Store, and it comes with just two changes. For enterprise users, the most notable one is that the launcher now supports fully managed devices in Microsoft Intune, which means IT admins can now completely customize the home screen experience for users. This includes choosing a wallpaper, home screen layout, and even the availability of the feed.
The only other change in this release is that app icons can now automatically be added to the home screen when a new app is installed. This already worked in some older versions of Android, but presumably because of API changes, it wasn't available for those on Android 8.0 or higher. With this new version, the functionality should be back.
If you'd like to try out the new features, you'll need to download Microsoft Launcher from the Play Store and enroll in the beta program from there. If you're not in the beta program and don't want to be, you should be getting version 5.7 of the launcher instead, which includes some design changes to the Feed and a more conversational UI for Cortana.