New Android 4.3 versions found on Nexus devices

According to a report by, Android 4.3 versions JWR66D and JWR53F have been spotted running on Nexus 4 and Nexus 7 devices.

If you break down the build numbers (JWR66D and JWR53F,) this is what they tell us:

  • ‘J’ tells us that they are Jellybean builds from the second quarter of this year
  • ‘R’ and the final number is x-th day in the quarter, in this case the 66th and 53rd.
  • The final character remarks the build of the day, the D is the fourth build, the F is the sixth build of that day.
  • What the ‘W’ means is so far unclear. This means both versions are from the end of May, beginning of June.

Myce found traces of these new Android 4.3 builds by monitoring the user agent strings, which is used by browsers to identify themselves.  Thanks to their tracking abilities, they found the following strings with the devices they were running on respectively: JWR66D – Nexus 7 and JWR53F – Nexus 4.






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