Google has posted binary images and hardware support files of Android's version 4.4.4 KitKat in their Google Developers domains, for the use of restoring your Nexus model's original factory firmware and for users of the Android Open-Source Project, respectively. The new update is here with the build number, reading as KTU84P. The lately release fresh images and drivers are available for Google Nexus devices including, LG Google Nexus 5 or "hammerhead" (GSM/LTE), ASUS Nexus 7 2013 or "razor" (WiFi), ASUS Nexus 7 2013 or "razorg" (Mobile), Samsung Galaxy Nexus 10 or "mantaray", LG Google Nexus 4 or "occam", ASUS Nexus 7 or "nakasi" (WiFi) and ASUS Nexus 7 or "nakasig" (Mobile).
So, whats new in this build of Android KitKat? As reported by Android Police, this brand new update will deal with security fixes, which is related to CVE-2014-0224, that is an OpenSSL bug, basically allowing a man-in-the-middle attack. This is something much alike the Heartbleed bug, which is already fixed in the Android 4.4.3 KitKat update, earlier. We also hear some of the members from the XDA-Developers forum reporting on receiving a 2.5 megabytes light OTA update of the build on their Nexus 5 smartphones.
Source: Google Developers 1, 2, Android Police, XDA-Developers