If you have a Sony Xperia U have good news, as it is already officially deployed worldwide an update of this model that improves stability and performance. Yes, the version of your operating system remains in Ice Cream Sandwich (Android 4.0.4).
The new version of firmware is deployed 6.1.1.B.1.100 (which replaces the 6.1.1.B.1.89) and is certified PTCRB, as you can see in this link , and at Therefore you can be sure that it is official and no problem when you attempt to install. Incidentally, the version of the operating system kernel and remains unchanged in 3.0.8, which has a fairly high reliability, it must be said.
The particular model that receives the update is the ST25 , which corresponds with the Sony Xperia U, so it has been known so far are some Asian countries which have already Begin to get the update (in all cases by specific computer software Sony PC Companion). Yes, it is confirmed that improving service also comes through OTA (Over The Air), which is easier because the process is performed directly in the terminal.
Improvements that some users have indicated that they are present
As they have said some of those who have already installed the new update (especially in Malaysia), some improvements that seem to be included in the new firmware for the Sony Xperia U are a better battery management, fewer failures when run several applications simultaneously, and also that the operation of the terminal can be seen more fluid . Yes, no new applications or existing inclusions. Come maintenance improvement in form.
Obviously, installation is highly recommended, as all official firmwares is important to have installed as it always improves the reliability and stability of the corresponding terminal. In this case the penalty is that the Android version does not improve (or the kernel), but when you get 6.1.1.B.1.100 version it is best to proceed with the upgrade . In Spain in particular has not confirmed the date to be deployed.
Via: Xperia Blog