There was a class action lawsuit filed just a few months after an upgrade was released: http://mashable.com/2015/12/31/iphone-4s-ios-9-lawsuit/#l.Zf4TnDvaqi ht

There was a class action lawsuit filed just a few months after an upgrade was released: http://mashable.com/2015/12/31/iphone-4s-ios-9-lawsuit/#l.Zf4TnDvaqi http://mashable.com/2015/12/31/iphone-4s-ios-9-lawsuit/#l.Zf... Edit: I'm not sure if this has been fixed with the later iOS 9 versions.