Apple has put out a patch for iOS 6.1 that’s just for the iPhone 4S. It’s intended to fix a problem with cellular-wireless networking on this smartphone.
The changelog from Apple is just a single line: “This update fixes an issue that could impact cellular performance and reliability for iPhone 4S”.
iOS 6.1.1 was released after the wireless carrier Vodafone warned its customers to not install iOS 6.1 on their devices. With the update, Vodafone has withdrawn this advisory.
Getting the Update
Those with an iPhone 4S have two options for installing iOS 6.1.1; they can hook their smartphone up to a computer running iTunes, or they can download the new version directly to their handset by going to Settings > General > Software update.