The firmware update was pushed out as a part of Apple’s SSL security fix, which also ushered in iOS 7.0.6 for more recent devices. iOS 6.1.6 was released solely for the iPhone 3GS and the iPod touch 4th generation.
P0sixspwn-the jailbreak tool created by the tandem of iH8sn0w and new Apple employee Winocm-has been updated to support the just-released iOS 6.1.6 for an untethered jailbreak.