Software update
Please help me to update my iPhone 6S with software 12.5.6
iPhone 6s Plus, iOS 11
If your device is running iOS 12.5.6, it cannot be an iPhone 6S Plus. Instead, it has to be an iPhone 5S, 6, or 6 Plus. Neither can be updated further.
2 replies
If you have an iPhone 6s, it can run iOS 15.6.1
Software update