Windows Phone Central/xs2K/The Verge

Looking for the latest unreleased smartphone or smartphone OS? Well, aside from the random watering hole, Craigslist might be your best bet.

Someone by the screen name of xs2K claims, in a post on the Windows Phone Central site, to have purchased a phone off Craigslist that's running an as-yet-unreleased update to the Windows Phone 8 OS called General Distribution Release 3 (GDR3).

That's an update that will let Win Phone 8 look nice and pretty on big-screen devices such as mini tablets and phablet-type gadgets like Nokia's allegedly upcoming big-screen Lumia 1520 phone.

Screenshots posted by xs2K (and picked up by The Verge) show several new features for Win Phone 8, including:

a Driving Mode feature that allows for automatic muting of calls and texts,

the ability to close apps in the multitasking view,

screen rotation,

support for custom sounds on text, voice mail, e-mail, and reminders, and

the ability to restore from backup using Wi-Fi during initial setup.

The Verge says it has confirmed that the screen shots and new features are the real deal. It also says GDR3 will debut first on the Lumia 1520 and an HTC Harmony device, and that it's expected to start moving to existing devices later this year.

GDR3 is expected to be the last Windows Phone 8 OS update Microsoft releases before it introduces Windows Phone Blue, the Win Phone update designed to bring the Win 8, Win RT and Win Phone 8 app models and developer platforms more into sync. Supposedly the Windows Blue update includes new programming interfaces, kernel updates, and some user interface enhancements.