Microsoft Flight Simulator will go into closed beta at the end of this month.
Closed beta testing for Microsoft Flight Simulator is scheduled to begin on July 30 once the build goes through final testing.
Those who participated in the alpha will be granted access to the closed beta, and recently, more alpha invites have been sent out to those who signed up. More invitations to the closed beta will be set out to Insiders as things roll on.
If you get an invite, be sure to look over the the minimum and recommended specs.
The latest update, Alpha 5 build 188.8.131.52, has also been deployed. The update fixes some bugs, improved the flight model, tweaked some of the weather, made some changes to some of the airports, planes, and more.