I have Iphone 4 , and it has IOS 5.5.1 , I want to update it to IOS 8 because viber whatsapp all other applications didn't work on it anymore , it is jailbroken , I don't know about these issues and I want to ask if I updated the IOS through Itunes , does the jaibreak fail and the sim lock ? or what should I do please help.
Best
Best