According to T-Mobile support, the Nexus 4 is scheduled to receive a new build of Android 4.3 any day now. The build number is JWR66Y, which differs slightly from the JWR66V that rolled out a few weeks ago. The only improvement they list is for “security,” so this likely is incredibly minor. Also, the jump from “V” to “Y” shouldn’t get you all that excited anyway.
The update should become available today, at least in some form, probably a staged rollout. The update is 1.8MB in size.
Via: T-Mobile Support