Apple has released an update to iOS to fix performance problems that led Vodafone in the UK and 3 in Austria to warn iPhone 4S owners against upgrading to the new software.
Vodafone warned iPhone 4S owners about possible 3G performance problems caused by iOS 6.1, the mobile operating system update that Apple released last month. The problems were believed to be intermittent but apparently hard to diagnose.
Apple has quickly released a 6.1.1 update for iOS, saying that the update fixes an issue that could impact cellular performance and reliability for iPhone 4S.
iOS 6.1 was released on January 28th and included several minor new features for PassBook and for music playback, improvements to Wi-Fi and security fixes.