Winocm and iH8Sn0w hackers working on untethered jailbreak iOS 6.1.3-6.1.5finally released a finished product. The utility is named p0sixspwn.
P0sixspwn can be used to untethered jailbreak of devices with any chips running on iOS 6.1.3, 6.1.4 and 6.1.5. The utility is free, you can download it from this link. While only the Mac version of p0sixspwn has been released, work on the Windows version continues.
In the near future, we will post detailed instructions on how to untethered jailbreak iOS 6.1.3-6.1.5 using the p0sixspwn utility.