Download iOS 6.1.1 for iPhone 4S. Apple has just released iOS 6.1.1 update with a build number 10B145 to the iPhone 4S users only, which fixes the iPhone 4S reliability, 3G connectivity issues and other bugs. You can download the iOS 6.1.1 from the given link below…
iPhone 4S owners can update their devices over-the-air update, by going to Settings > General > Software Update!
Release notes: This update fixes an issue that could impact cellular performance and reliability for iPhone 4S.
Note: This iOS 6.1.1 update is only for iPhone 4S owners! Stay away from updating to iOS 6.1.1 if you depend on Ultrasn0w, Gevey SIM or wanna jailbreak your device.
Download iOS 6.1.1
iPhone 4S – iPhone4,1_6.1_10B142_Restore.ipsw