Q: I have already Unlocked Bootloader, does i can get 4.3 update?
A: Yes, you can get it but you can't install it via OTA or PCC (See this)
Q:What happen when I root my devices, but i dont have unlocked bootloader.Can i get update too?
A: Yes you can update it
Q:How to update while my device has not to get it?
A: Just wait FTF and flash it.
Q: If i get update, how to i can backup my contact, sms and games?
A: You can backup it use Sony Backup and Restore app [Restore 4.3 Method*] ( Or Use App Backup & Restore) in your phone/or used PC Companion to backup
Q: I have rooted my devices, what happen after I update?
A: Your devices will lost root, so you must root again.See second thread
More question you can add in comment section below.
*Only for update 4.3, Install manual apk if you want to restore backup from 4.1.2