Google is currently updating their LG Nexus 5 smartphone with the new build of Android 4.4.4 KitKat version. The new software update roll out is only limited to a number of countries, from Australia, New Zealand to India, as reported. Users in the region will be receiving an over-the-air update to their Nexus 5 handsets, which will bring the new refurbish, with build number, KTU84Q, bringing new radio image and fixes to the networks in the aforementioned regions. This version of Google's build is dubbed as Android 4.4.4_r2.
Alongside, Google has also posted factory images and binaries for the new build on their official Google Developers webpage, that'll some in handy for the use of restoring your Nexus 5's original factory firmware and binary hardware support files, for users of Android Open-Source Project. Factory images and binaries for Nexus 5 "hammerhead" (GSM/LTE) is read as Android 4.4.4 Release 2 (KTU84Q).
Source: Google Developers 1, 2, Android Police, Pocketnow