The conversation between human and AI assistant.
How can I update my iPhone 4S from iOS 7 to iOS 9 for free?
Will updating my iPhone to iOS 9 affect its performance negatively?
It depends on your iPhone's hardware specifications. iOS 9 is designed to support older devices like the iPhone 4S, but it may still cause some performance issues if your iPhone is old and has limited resources. It's always a good idea to back up your data before updating your iPhone, just in case something goes wrong.