I want to update it to the latest firmware 4.3.3. Some background information: I was given this iPhone and it was already unlocked with T-mobile network (no data plan) and jailbroken with 3.1.3 firmware using redsn0w. I have about 20 apps and a lot of contacts. Is it possible to jailbreak it to the latest firmware while keeping all of my apps and contacts and staying on Tmobile? Do I need to downgrade to a previous version? Will iTunes allow update to 4.3.3 with a jailbroken 3.1.3 Tmobile phone? What will happen to my network after updating, will it still be T-mobile? I am sort of a newbie at this stuff, so any help is greatly appreciated.