Now sony has started rolling out much awaited Android Jelly bean update for Sony Xperia J (ST26i) Model.Sony Xperia J is the third of its kind to get updated to Android Jelly bean version 4.1.2 ( Build number 11.2.A.0.21 ).
Here is a screenshot of jelly bean updated updated Sony Xperia J.
As you can see the Jelly bean provides a power saver option which enables your device to cutoff data usage,Wifi and other powers consuming features when the phone is ideal.
How to Update ?
Just connect your phone to your PC or Mac and start the PCC or Mac bridge and you will get a option to upgrade.