If you've recently updated your Nexus device from Jelly Bean to KitKat, there's a chance you're already being notified of an OTA update to KRT16S. If you're wondering what's changed, the collected list of source commits has been posted by Al Sutton. Most of the tweaks are pretty minor, including an improvement to the backup service, a few updated APNs for assorted carriers, and code to handle rare issues with the 3G Nexus 7 (2012) radio.
The first notable update for KitKat has just been released across most of the major AOSP and Nexus channels. According to Google software engineer Conley Owens, the KRT16S build includes bugfixes for the original Nexus 7 and Nexus 7 2013 (WiFi and mobile versions), Nexus 4, and Nexus 10. The binaries have already been added to the Nexus repository.
Screenshot credit: Tron87, Nathan Sparrow
Google has also updated the factory images for the relevant Nexus devices.
Back on Halloween, Google promised that proprietary binaries and factory images for the Nexus 4, Nexus 7, and Nexus 10 would arrive shortly after devices received their OTA updates. Even though some OTAs haven't even rolled out yet, as of a few minutes ago, all modern Nexus devices now have Android 4.4 KRT16O factory images and drivers available for download.
This means you can flash stock Android 4.4 onto any supported device, even if an OTA either wasn't available yet or wouldn't work for some reason.
Following closely behind the 2012 and 2013 Nexus 7 KitKat OTA updates, it's finally the Nexus 10's turn to receive the same treatment. You can now flash the 219MB KRT16O Android 4.4 build without having to wait for your tablet to alert you, no matter what your rooting/bootloader situation is. Of course, if you've modified the system partition in such a way that the OTA won't apply cleanly anymore, you have to either revert those changes or wait for the factory image.
In a pair of exciting tweets (and a Google+ post), the Android team has announced that the WiFi Nexus 7 (both 2012 and 2013 models) will begin getting updated to Android 4.4 KitKat today, while the mobile data-enabled Nexus 7 and Nexus 4 will get the update "soon."
Starting today, Nexus 7 (2012 and 2013) and Nexus 10 will be getting a tasty update to Android 4.4, KitKat
— Android (@Android) November 13, 2013
Did you know it's possible to unlock your Nexus 5 bootloader without wiping user data? If your device has already been rooted and relocked for optimal security, then unlocking is just a button tap away thanks to the latest update to BootUnlocker. Support for Google's latest flagship phone was just added with an update to version 1.4 of the app from XDA member segv11. Sadly, both generations of the Nexus 7 from ASUS remain unsupported.
Just a quick note to anyone waiting for full OS factory images and drivers for existing Nexus devices (outside of the Galaxy Nexus, which bit the dust with KitKat) - as is customary, they will follow over-the-air updates released according to Google's favorite timeline: "in the coming weeks."
The Nexus 5 factory images will be out later today, but don't sit there hitting F5 expecting factory images for the Nexus 4, 7 (new and old), or 10 to pop up any time soon.
Update: Here's an official Google Support answer stating the GNex will indeed be stuck in 4.3-land for eternity.
At the bottom of Google's official Android 4.4 announcement post on the company's blog, some rather pertinent information for current Nexus / GPE device owners is thrown in: OTA update news!
KitKat will be coming to the Nexus 4, Nexus 7 (presumably both models, but not explicitly stated), Nexus 10, and the Google Play Edition Galaxy S4 and HTC One.
We've featured various incarnations of the Nexus 10 on dozens of deals at this point. If you want a cheap, powerful, 10-inch AOSP tablet and you don't have one by now, you've got no one to blame but yourself. That said, if you're looking for one last chance at a deal, we've got your back. Woot has the 32GB version of the Nexus 10 available for $329.99 plus $5 shipping.