How to downgrade iPhone 5S from iOS 10 to 7?

As others have mentioned, there are a couple reasons you should not waste your time with such an effort:

1. This is no small hurdle to overcome, but, honestly, I don't know of any way to downgrade iOS. Many years ago, you could move between versions quite freely. For the past few years, though, Apple has made it necessary for the iTunes Store to approve the re-loading of iOS on a device… It will not approve an older version. I know of no way to bypass that process. Must Read:How to put mp3 on iPhone ?
2. If you were successful in downgrading, you would effectively be loading a less secure version of iOS. You could be opening yourself to vulnerabilities with your security and privacy.
3. You may find that some recently released/updated apps either no longer run, or you're stranded on an old version of the app and there's no way to upgrade. For example, I believe Chase Banking is one such app. If you're on iOS 7, the current version of Chase won't run and you get a message that you need a newer iOS. DirecTV is another and there are many more. As time goes on, the list of apps you'll be able to run will continue to diminish. Must Read:iPhone contacts disappear

So, no, I would not recommend downgrading even if you found a way to do it.

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