IOS 6.1.3 update

The iOS 6.1.3' update is a software update released by Apple that patches the jailbreak exploit used by the jailbreak tool, Evasi0n, which basically means that it won't allow you to jailbreak if you update to 6.1.3, or any jailbreak for that matter. The update also "fixes a bug that could allow someone to bypass the passcode and access the Phone app." (on Wikipedia.org), Improves the maps on Japan, and fixes security bugs. The update was released to iOS users on March 19, 2013.

iOS Devices:

 * iPhone 3GS, 4, 4S and 5.
 * iPod Touch 4th and 5th generations.
 * iPad 2, 3, 4 and the iPad Mini.

UPDATE!!
'''If you are running iOS 6.1.3, you can still jailbreak your device. Unfortunately, you can ONLY jailbreak non A5 devices (iPhone 4, 4S and iPod Touch 4th generation only as of April 1st!), using a semi-tethered jailbreak, which means you can untether it, but you are gonna have to start with a tethered jailbreak first by using Redsn0w and using a 6.0 IPSW.'''