i0n1c, the hacker who discovered the exploits on the basis of which the solution was launched jailbreak for iOS 4.1.x, has a vulnerability through which iDevices can be jailbroken on iOS 6.1.3. The hacker demonstrated the functionality of the vulnerability, so it's pretty clear that it exists, but unfortunately we won't ever have it available to do jailbreak pe iOS 6.1.3. i0n1c is strongly against releasing untethered iOS jailbreak solutions for free, so don't expect to see any for iOS 6.1.3.
