The build version is KRT16S and some users have already received it, but the rollout appears to be rather slow. The update is 238MB in size, but we don’t have the full picture yet, as it’s unclear whether the Nexus 4 will get all the features found in the Nexus 5 – we know it won’t get some.
KitKat is also expected to land on Nexus 7 devices shortly, but once again the rollout is slow. Classic Google.