iOS 6.1.1, which was sent to developers last Wednesday, was made available yesterday to owners of iPhone 4S. In the release notes accompanying the software update, Apple says that it "fixes a problem that could affect the performance and cell communication reliability for the iPhone 4S."
The update is not for other Apple devices running iOS, including the latest iPhone 5 or even the 3G models of the iPad, but only the iPhone 4S.
iOS 6.1 was release in late January to provide a set of fixes and enhancements including support for mor 4G LTE mobile networks operators for the latest Apple devices and also a feature that allows you to buy movie tickets with Fandango service. Apple has also added an option for subscribers to iTunes Match to download songs individually from iCloud.
The software update also bring other changes such as new behaviors for the Passbook app, the virtual card holder from Apple; improvements for Safari and improved controls for music playback from the locked screen. And finally a change of background in "Maps", an Apple-made mapping app.
Despite the rapid adoption of iOS 6.1 by iPhone, iPad and iPod Touch owners, this version of the software has been source of problems for some companies and even mobile operators such as Vodafone in the USA. In the American press, we learned that last week, the mobile operator has sent a message to its subscribers asking them to not update their devices with the latest vesion Apple iOS because of "trouble connecting to the network, to make or receive calls or texts, or connect to the Internet." that it trigger.
Aside from the problems of 3G networks connexion on the iPhone 4S because of iOS 6.1, there's also a synching issue between Mail app and Microsoft Exchange mail servers, which has forced some companies using Exchange to block access to the mail service from iOS 6.1 devices.