In an unexpected move, Apple has released a new version of iOS exclusively for iPhone 5 owners. iOS 6.1.4 upgrades the audio profile for the device's speakerphone, and so far doesn't appear to make any other changes. The update applies to both GSM- and CDMA- equipped iPhones.
The download is just 11.5MB, and should be available either through iTunes or by selecting Software Update under the iOS Settings app's General tab. 6.1.4 appears to be solidifying a recent trend with Apple, in which the company puts out quick point releases meant to fix problems, often on only one or two devices. iOS 6.0.2, for example, was only available for the iPhone 5 and iPad mini