This is the untethered exploit installed by the Pangu 8.0-8.1 jailbreak tool. If you jailbroke your device with Pangu 8.0-8.1, this untether has already been automatically installed for you.
Version 0.4 of this package fixes the issue where, on 32-bit devies (iPod 5, iPhone 4S/5, iPad 2/3/4, iPad Mini 1), applications (particularly Safari) would randomly crash while being used.
Note: before installing updates to this package (which will require a reboot), if, after the first time you ran Cydia on this device, you used the iTunes "restore from backup" feature (or otherwise used iTunes or iCloud to put old data back on you device), please now reinstall Cydia Installer (by going to that package and tapping Modify, Reinstall, and Confirm) to make sure your device can safely reboot with a passcode enabled.
You can update your Pangu Untether from Cydia. If you haven't jailbroken already, you can be instruction on how to jailbreak your specific device via the iClarified Jailbreak Wizard.
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