As you know, iOS 6.1.3 update was released by Apple yesterday in order to fix the Lockscreen Passcode bug, and it brings several Maps enhancements in the Japan region. As it was predicted, the update contains patches for Evasion exploits used to perform jailbreak on iOS 6 devices.
With the iOS 6 released, users were happy because they were able to perform an untethered jailbreak on their iPhone, iPad or iPod Touch using Evasion jailbreak tool. As you know, when Evasion was revealed, the Evaders team confirmed the fact that the tool uses several security exploits in order to perform an untethered jailbreak. And now, with the new update that patches some of these exploits, we still do not know if we will be able to perform jailbreak in the future on our iOS 6.1.3 devices.
Recently, MuscleNerd sent a tweet confirming what we already know; the fact that the new update released by Apple kills the untethered jailbreak performed by Evasion. He also mentioned the fact that the kernel is available for iPhone 3GS and later, iPod Touch 4th generation and later, iPad 3 and later.
As a comfort, the Evad3rs team mentioned the fact that they still own certain major exploits ready to use, besides what they have already used when creating Evasion. I assume that this means that we will be able to see an Evasion update capable of performing untethered jailbreak on the new iOS update, sooner or later.
If you rely on iOS 6 jailbreak on your device, then you should stay away from the new update, at least for some time. Moreover, if you do not encounter any problems with the lockscreen security bug and you do not need the Japan Maps update, then you definitely should not upgrade your device to the latest iOS 6.1.2, at least for now.
As a mention, you should hurry to prepare your jailbreak device for the future update. This means than you need to save your SHSH blobs, to use Safe Mode and to wait to see if there will be something new in this respect.