Hello all, My nephew just gave me his iphone 4s last week (he just bought a new one). Anyway, his ... my 4s iphone is running on 5.1.1 iOS, it also was unlocked from AT&T to use on T-Mobile network, and jail broken. My question is does it worth updating it to the new iOS, and do I have to re-unlock it for it to work with T-Mobile. I understand that I still need to re jail-breaking it after any update. The reason I want to update is that I can't use the Facetime aps on the phone due to old version of iOS. Any suggestion or recommendation is very appreciated. Thank you all in advance.