Sony has made available the Android 4.1.2 Jelly Bean platform for its Xperia S devices, but it has been already brought to commercially available handsets, it seems, and is now up for grabs for all those interested in getting it for a spin.
The OS comes with firmware version 6.2.B.0.68, and it appears that it can be installed only on Xperia S (LT26i) devices.
According to a recent post on the XDA-Developers forum, users should not try cross-flashing it, as it might brick their devices.
Those who would like to download and install the leaked software will find all the necessary instructions in the aforementioned forum post.
They should back up all the data on the device before proceeding with the installation, so as to make sure that nothing is lost. However, we would recommend waiting for the official release to arrive from Sony.