Available as a free download now, iOS 6.1 adds LTE (long-term evolution, marketed as 4G LTE) capabilities to 36 additional iPhone carriers and 23 additional iPad carriers.
"iOS 6 is the world's most advanced mobile operating system, and with nearly 300 million iPhone, iPad and iPod touch devices on iOS 6 in just five months, it may be the most popular new version of an OS in history," said Apple's senior vice president of Worldwide Marketing Philip Schiller.
"iOS 6.1 brings LTE support to more markets around the world, so even more users can enjoy ultrafast Safari browsing, FaceTime video calls, iCloud services, and iTunes and App Store downloads."
Additional updates include the ability to use Siri to buy movie tickets via Fandango in the US. iTunes Match subscribers can now also download individual songs to their iOS devices via iCloud.
iOS 6.1 is compatible with iPhone 5, iPhone 4S, iPhone 4, iPhone 3GS, iPad (third and fourth generation), iPad mini, iPad 2 and iPod touch (fourth and fifth generation), though some features may not be available on all these products.
Features included on iOS 6 include Siri with multi-language support, Maps and Facebook integration with the ability to post from Notification Centre, Siri and Facebook-enabled apps.
Other features include Shared photostreams via iCloud and Passbook.