First of all, I don't own an iphone, my wife has one but I've never really used one other than messing around a little bit with my wife's, so please bear with me. We live in Venezuela, because of the economy getting good phones is rather hard. My wife has three sisters, two of them live abroad (in Germany and Switzerland). They both had iPhones 5, they eventually got iPhones 6 (I think one of them a 7 now), so the 5's went to my wife and the other sister that lives in Venezuela. This year, however, when iOS 10 came out, my wife's sister upgraded her phone and it got blocked, she said it asked her for a number that was given at the time of purchase basically bricked itself when she didn't know it... thing is, both iPhone 5's were bought used, so we're the third owners, the original owner said that she had a number given on a piece of paper when she bought it, but so long ago that she lost it and has no idea what could it be. So basically now my wife's sister has a bricked iPhone that can't do anything with, my wife doesn't want to upgrade her phone at all in fear of getting it blocked as well, and I really don't know what number or code they mean so haven't been able to find anything about it (I'm guessing it's not the PIN number). Anyone have any idea about what that number might be, and what to do about it to unlock the bricked one and just in case, prevent it from happening to my wife's?