Hello, I have an iPhone 4s, 16 gb and 5.1.1 version of iOS. Is it possible to upgrade it to 7.x.x? I have tried, but I did not manage to do it, as iTunes keeps telling me that "This device isn't eligible for the requested build". I've already tried what the support page of apple tells, still no result. So, is it possible or not? If not, can I upgrade to 8.1? I've tried this too, with iTunes, and got the same message "This device isn't eligible for the requested build". From what I've read, 8.1.2 is available for jailbreaking only with Taig, which works only on windows, and I've got a Mac, so I can't go this way. (yes, it's jailbroken) Help, please. Thanks.