Didn't see this announced but they have an insider program
FAQ Link
Do you share our passion for flight? Are you interested in working directly with us to deliver the next generation of Microsoft Flight Simulator? The Insider Program is for you! Join your fellow aviation enthusiasts to get exclusive behind-the-scenes updates from developers and partners, gain access to preview builds, and advanced content updates before the general public. Best of all, you'll become part of the Microsoft Flight Simulator team responsible for providing feedback and recommendations critical to helping deliver the very best experience! You, matter.
FAQ Link