To add on, if we're talking about the iPhone 3GS and 4, iOS 6.1.3 is tethered jailbreakable, always will be (for the iPhone 4 at least). iOS 7 is not released, it's beta seeded, a huge difference. 6.1.3 and 6.1.4 are almost guaranteed to not see an untethered jailbreak outside of the 3GS old bootrom on 6.1.3. The 4S and iPad 2 and newer devices will never see the light of any type of jailbreak for 6.1.3 or 6.1.4 considering that the dev teams and major players are attempting to save exploits and delivery methods in hopes that they'll work on iOS 7 despite the completely restructured security and sandboxing.