Sony has made good on its promise to start delivering the Ice Cream Sandwich update to its 2011 Xperia smartphones. As of right now, Ice Cream Sandwich is available for the Xperia arc S, Xperia neo V and the Xperia ray. If you own one of these devices and happen to live in either Sweden, Iceland, Demark, Finland or Norway, feel free to start the update process now.
When Sony first revealed its intentions to update the line of Xperia smartphones, it also mentioned why the update won't be pushed out over-the-air. Due to hardware limitations on the 2011 Xperia devices, Sony wants users to decide whether it's worth upgrading. Sony said Gingerbread is very stable, but the extra power required to run Ice Cream Sandwich may cause some devices to take a performance hit.
In order to determine if the update is available for your specific carrier and device, remove the battery from your phone and make a note of the eight-digit SI number. Once you do that, check out the chart Sony created to make sure the update is available to you. From there, it's just a matter of going to the Sony Mobile site and downloading your respective update.
Source: Sony Mobile