Hi and welcome to the community! Since you're new please be sure that you have checked out our Discussion guidelines.
I suggest that you download and install our program PC Companion at your PC:
http://www.sonymobile.com/global-en/tools/pc-companion/
When you have installed PC Companion, connect your phone via USB-cable and PC Companion will tell you if you have an available update. You will also receive a step-by-step guide in PCC that guides you through the update.
