Some guy that chose to remain anonymous, claims he has bought the AT&T's Developer Edition of Nokia Lumia 920 from Craig's List and it was running on the upcoming WP8 GDR3 Bittersweet Shimmer update.
He shot a video of the new features, while wearing a PSY mask with a hateful message to Apple. Anyway, the new features he found so far include the added notifications on the Glance screen (the one that always shows the clock on AMOLED Lumia phones).
The next major features is the option to close apps in the task switching interface.
Other major update supposed to come with the GDR3 firmware is the support for quad-core processors and 1080p displays.
Here is the video:
The Bittersweet Shimmer update is supposed to hit the compatible WP8 Lumia smartphones by the end of the year. Let's hope Microsoft will speed those updates a little bit after the Nokia acquisition.
Source (http://www.youtube.com/watch?v=ZCNlDXICySw) | Via (http://www.phonearena.com/news/New-video-shows-off-a-couple-of-features-from-the-GDR3-and-Bittersweet-shimmer-update_id47214)
GSMArena.com