At the start of the year, Microsoft released Microsoft Launcher Preview, a new version of its home screen replacement for Android, built on a completely new codebase, which was version 6.0 of the launcher. Being significantly rebuilt, it was missing some features from the regular version of the launcher, and Microsoft spun it off into its own Play Store listing, leaving the current version of Microsoft Launcher, as well as the regular beta, untouched.
That's beginning to change though, as Microsoft is now rolling out Microsoft Launcher version 6 to users enrolled in the beta program for the regular version of Microsoft Launcher. The change was first spotted by Dr. Windows, and we've been able to confirm that this is indeed the case, though the beta version is a few builds behind.
There are a few visual changes with this version of Microsoft Launcher, with new icons all around, among other things. Over the past few months, Microsoft Launcher Preview received updates that brought it up to par with the previous stable version, adding support for hidden apps and re-enabling backup and restore. Notably, however, Microsoft Launcher Preview added support for landscape mode, and the version released for beta users doesn't seem to support it based on our testing. Presumably, it will be added before a general release. It's also worth noting that if you backup your settings in Microsoft Launcher Preview, it's currently not possible to restore them in the beta release, seemingly due to the small difference in version numbers.
Microsoft Launcher 6 is expected to be the version that ships with the Surface Duo, optimizing the experience for dual-screen devices. With reports suggesting the device is coming soon, it makes sense that this version is getting closer to being ready for primetime. If you'd like to try out the new version, you can install Microsoft Launcher from the Play Store, then scroll down to find the option to join the beta program. The latest version should be available as an update shortly afterwards.