Developer Plain Vanilla Games is now allowing some people who signed up to test the upcoming Windows Phone version of their trivia app QuizUp to download a private beta version of the app. The company announced its plans to release QuizUp for both Windows Phone and Windows 8.1 in February.

As we reported earlier this month, these testers will be under a pretty strict Non-Disclosure Agreement which, among other things, forbids them from posting any public screenshots or reviews of the QuizUp Windows Phone beta. In other words, don't expect a lot of info about the app to leak out before it is officially released.

The actual development of the Windows Phone QuizUp version is being handled by Gateway Apps. QuizUp already has 32 million users worldwide with its iOS and Android versions, and lets gamers play online trivia matches with friends and strangers.

Thanks to William, Trambak and the many other folks who tipped us!