Last month Sony Xperia ZR LTE received a software update to Android 4.2.2, while 3G model owners were left on Android 4.1.2. But this will change as of this week, because Sony has started pushing out Android 4.2.2 to the 3G Sony Xperia ZR variant.
The new software updates the device to firmware build 10.3.1.A.2.67 making the transition from Android 4.1.2 to Android 4.2.2 which fixes some problems, adds Quick Setup feature in the notification bar, lockscreen widget option and improves the overall performance of the phone.
The latest firmware is rolling out through Sony PC Companion or OTA (over the air). Enjoy!