Sony Mobile released the new Android 4.0 Ice Cream Sandwich Beta ROM for selected Xperia range. Sony has made a number of improvements to the ROM, including an updated UI, improved lockscreen, activated GSM modem and FM radio and a quick dial.
Google Mobile Services (GMS) apps (for example Gmail, Google Maps and Face Unlock), Bluetooth and Wi-Fi are NOT included in the beta release due to that they are still waiting for the certification and type approval to be finalised.
This beta update from Sony Mobile is only released for three handsets (the Xperia arc S, Xperia neo V and Xperia ray). You need to be running software version number 4.0.2.A.0.42 before upgrading and must have bootloader unlocked .
For more information visit Sony Mobile Developer Blog