Update your iPhone, iPad, or iPod touch Plug your device into power and connect to the Internet with WiFi Tap Settings > General > Software Update Tap Download and Install If a message asks to temporarily remove apps because iOS needs more space for the update, tap Continue or Cancel To update now, tap InstallA link to download the iOS 936 has been added to this post iOS Firmware for iPhone 4 S can be downloaded from here Signed IPSW files work well with iTunes but unsigning them may result in a device that cannot currently be restored by the iTunes program alone – you'll need to plug your iPhone or iPad into iTunes before proceeding The problems start with sheer physics The iPhone 4s is an anachronism in our big smartphone world — iOS 9 is made for bigger phones That makes doing most things on the 35inch diagonal display
Ios 9 2 1 Improves Iphone Speeds