The Sim Update 9 Public Beta is now live, and should be available for users on all platforms within an hour.
If you are interested in joining the open beta, please see our post here on details how:
https://forums.flightsimulator.com/t/read-first-welcome-to-sim-update-9-beta/507612/1
Release notes for the beta are available for viewing here:
https://forums.flightsimulator.com/t/sim-update-9-release-notes-1-25-4-0/507653