In September 2014, Microsoft took the wraps off "Denim," the latest firmware update for Lumia phones that officials said would be available in the fourth quarter of 2014.
On December 17, Microsoft began making Denim available to Lumia 520, 720 and 1320 users in China, according to Windows Central. And on December 18, Microsoft officials told Lumia customers to expect Denim to start rolling out soon to more Lumia phones.
From that post:
"The Lumia Denim update has started rolling out to a limited number of devices in selected markets, and will continue arriving in waves by device. A wider rollout of Lumia Denim to all Lumia smartphones running Windows Phone 8.1 is expected to begin in early January, following partner testing and approvals."
Users need to have the previous firmware update, Cyan, installed in order to install Denim. (And yes, as a Verizon user, I know Verizon has still not pushed Cyan or Windows Phone 8.1 to us. The latest rumors suggest Verizon is now planning to provide Denim, along with Windows Phone 8.1, 8.1 Update and Cyan, some century soon.)
Update (December 19): Microsoft's Joe Belfiore tweeted on December 19 that Icon users should be getting Denim (plus the 8.1, Update and Cyan rollup of updates) in "early 2015."
Denim includes a number of imaging/camera features, including camera quality and speed improvements; a new "Moment Capture" feature for 4K video recording on some of the higher-end Lumia phones; and support for new imaging algorithms, providing for crisper photos in daylight or low light. These imaging/camera enhancements are specifically for Lumia 830, Lumia 930, Lumia Icon, and Lumia 1520 models.
Denim also adds, as promised, live folders, SMS merging and voice activation for Cortana.
Before anyone asks, I do not know when Microsoft is planning to roll out a second General Distribution Release (GDR) update for Windows Phone 8.1. There were rumors earlier this year this would happen in the fall of 2014. I haven't heard a new target date.
On the mid- to low-end phone front, Microsoft has expanded carrier billing support to several new markets, including China (through China Mobile); India (with Idea); and Brazil (via Claro); and the U.S. (via Verizon Wireless). Carrier billing allows users to purchase apps through the Windows Phone Store without a credit card and instead via their wireless providers.
Following today's announcement, Microsoft now has carrier billing arrangements with 81 carriers in 46 markets, which officials say represents 46 percent of all subscribers worldwide, based on Ovum World Cellular Information Service data.
Earlier this week, Microsoft also made available an updated version of its free Windows App Studio tool, which enables app creation in a simpler way. The updated version adds support for the TouchDevelop touch-centric programming language; support for universal Web App Template (WAT) creation; and compatibility with the recently announced free Visual Studio 2013 Community Edition product. The new version of Windows App Studio is phasing out support for Windows Phone 8.0, however.