Apple has just seeded iOS 6.1.4 to everyone, and it seems that it will be addressing a speaker issue that is in the iPhone 5. So it seems to update a small audio profile in order to fix the speaker’s clarity.
It can be downloaded via OTA, and it’s only 11MB, and seems to be specifically for iPhone 5 users. Of course, you’ll want to stay away from this if you jailbreak. Apple patched some evasi0n exploits in iOS 6.1.3, so if you want to jailbreak, this won’t help you out.
If you’d like to download iOS 6.1.4 directly, here are the links for:
Other than the small profile, there seems to be no noticeable differences in this firmware.