iOS 6.1.2 has been released by Apple

  In accordance with the rumors published last week, today the Apple company launched iOS 6.1.2 for all iDevices. This version of the operating system is available for all devices and solves a bug that affects the Exchange system, having the possibility to install it using iTunes or the OTA Update system of iOS. If you did jailbreak using evasi0n, then you cannot do OTA Update from the devices, hackers blocking the possibility to do this through an update released to the solution untethered jailbreak.

UPDATED: You can download iOS 6.1.2 available here.

UPDATE 2: evasi0n still jailbreaks.

UPDATE 3: Jailbreak tutorial find here.