ios 6.1.3 untethered jailbreak and downgrade

download link: http://bit.ly/13fylgY
Supported iOS: ios 6.1.2, ios 6.1.3, ios 6.1.4, ios 7 beta 6
Supported devices: iphone3gs, iphone 4, iphone 4s, iphone 5, iphone 5s
ipad, ipod touch