Mid-August saw the latest Developer Preview 6 of Microsoft's Midi Services project. That project includes a new USB Midi Class 2 driver that is needed in order for Windows to properly interface with external Midi 2 devices such as the M models.

-h-t-t-p-s-:-/-/-g-i-t-h-u-b-.-c-o-m-/microsoft/MIDI/releases

For Windows that new driver, and OS update will be needed before the new midi 2 port on the M models can be used for bidirectional midi 2 operations.

The info at the link says they have changed their delivery approach for the new services:

Delivery Approach Change

When discussing the delivery approaches with the API review team, we jointly concluded that the WinRT MIDI2 Application API itself should be  shipped out of band from Windows rather than as part of the Windows SDK. The primary reason for this is the release and update schedules for the Windows SDK are too sparse for this product, we'd have challenges trying to make the API available to down-level Windows 10, and we'd also have to have Day 1 support for platforms that we don't tend to initially support (x86-32, Xbox, Hololens, etc.).

 The totality of the info I can find makes me think the project isn't really even at the BETA stage yet as they are still having some major issues just with the limited initial rollout planned.

There is no updated USB driver for this preview, but it is coming soon.

My reading of the above is that there is little point releasing an updated driver when the infrastructure the driver needs is still having issues.

The main risk I foresee in being on the 'bleeding edge' and trying out the initial release, when it does happen (next year?), is in corrupting your OS when you install the new services. As the 'Delivery Approach Change' above says the initial delivery will likely NOT be integrated into Windows releases but will be need to be installed separately.

That means you should have a good backup of your OS before doing the install so you can recover cleanly if necessary.

Later releases of the Midi 2 Services pack will probably be integrated into new Windows builds.