The Ice Cream Sandwich update that is rolling out to some of the 2011 Sony Xperia family brings with it Android 4.0.3 using the 2.6.32 kernel. Many have been wondering why Sony Mobile is taking so much longer to release ICS for its 2012 flagship, the Xperia S. Well judging from a snapshot of a leaked ROM the reason is likely to be that Sony is updating the Xperia S to Android 4.0.4 rather than 4.0.3.
The snapshot of the leaked ROM comes from the Xperia NX (SO-02D) – the Japanese equivalent of the Xperia S. It shows that the handset is running Android 4.0.4 and an updated 3.0.8 kernel. The firmware build number of this version is 6.1.A.0.405. Hopefully the firmware will bring with it better power management and hence longer battery life.

Via xda-developers.