Nokia Lumia 830 and Nokia Lumia 930 will soon receive Lumia Denim update?19
Not all of the phones being updated will be able to run such features. The Lumia 830, for example, won't be able to film in 4K. While it can do Moment Capture, it only does so with lower 2MP images. The feature allows users of certain Lumia models to long press on the camera button, which starts 4K recording at 24 frames per second. Each frame can be saved as an 8.3MP photograph.
While the Lumia Denim update was originally rumored to start rolling out in the fourth quarter, the latest buzz has the update being disseminated starting this month, and taking two months to complete. Besides the Lumia Denim firmware changes, the Lumia handsets will also receive Windows Phone 8.1 update 1. Among some of the features being added is the ability to wake up Cortana by saying, "Hey Cortana." It also adds Bing Weather and Bing Health and Fitness data to the Glance Screen. The camera will be faster between shots, and low-light image processing will be improved.
source: NPU via WMPoweruser