Posted on 31 March 2016
Hello Developers!
We’re pleased to announce that our Universal Windows Platform module is now ready to be released. All owners of GameMaker: Studio Master Collection will now be able to select UWP as an export target.
In order to receive this update, users must update their license from within studio:

Upon restarting, GameMaker will download any modules you are missing, including UWP.
We hope you enjoy developing games for UWP with GameMaker!
Be sure to let us know what you’re working on by contacting us on Twitter, Facebook or by submitting to our Showcase!
Thanks!
-YoYo Games