Xperia Z C6602, ZL Android 4.2.2 10.3.1.A.0.244 firmware update ftf

A month back on June 24, Xperia Z was officially update to  Android 4.2.2 Jelly Bean 10.3.A.0.423 firmware and some days back we saw another Jelly Bean 10.3.1.A.0.236  firmware OTA update being rolled on Xperia Z but only on developer handsets, which was a lot curious why such a firmware was rolled and users reporting it were very few.

http://www.xperiaguide.com/2013/07/30/download-xperia-z-c6602-10-3-1-a-0-244-firmware-update-ftf-file/