A purported screenshot from a Sony Xperia Z Ultra (C6833) allegedly shows the first picture of the Android 4.4.2 KitKat firmware update. The picture shows that Android 4.4.2 will arrive with build number 14.3.A.0.681, although if this is true, the final release is unlikely to have the exact same version number.
We can’t verifiy the authenticity of the picture but given the current Android 4.3 Jelly Bean firmware runs build number 14.2.A.1.136, there is every chance that KitKat will come with the 14.3.A.X.XXX build template. If true, it could mean that the update may be launched within weeks. We will keep you posted on further developments.