Microsoft has released Windows 10 SDK Preview Build 17692

MSIX Support
It’s finally here! You can now package your applications as MSIX! These applications can be installed and run on any device with 17682 build or later.

To package your application with MSIX, use the MakeAppx tool. To install the application – just click on the MSIX file. To understand more about MSIX, watch this introductory video: link

  Windows 10 SDK Preview Build 17692 released