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.

Note: Upgrading this package will require a reboot. Older versions of Cydia Installer (1.1.14 and 1.1.15) had a bug where, after using the iTunes "restore from backup" feature, rebooting while a passcode is enabled on your device would cause the device to not be able to boot. This can be fixed by reinstalling Cydia Installer after restoring the backup (by going to that package and tapping Modify, Reinstall, then Confirm) or by upgrading to a recent version of Cydia (1.1.16 or later).

Version 0.4 of this package fixes the issue where, on 32-bit devices (iPod 5, iPhone 4S/5, iPad 2/3/4, iPad Mini 1), applications (particuarly Safari) would randomly crash while being used.

Version 0.3 of this package fixes the issue where, on 32-bit devices (iPod 5, iPhone 4S/5, iPad 2/3/4, iPad Mini 1) a specific background process (launchd) would sometimes "spin", burning CPU and battery, or even heating up.

Please also note that rebooting can surface other problems unrelated to the untether or Cydia. For example, having incompatible tweaks installed can cause problems upon rebooting.

Version 0.2 of this package fixes an issue that caused Cydia Substrate to not fully load into many processes immediately after rebooting. After installing this untether update, you no longer need to respring after rebooting to make Cydia Substrate work.

The 0.2 update also solves the Safari and iMessage bugs that some users reported. (For developers: the issue with RWX pages was also fixed.)

As this update makes Substrate work more consistently, installing this update exposed bugs in Substrate 0.9.5013 for many users. It is important to also use the latest versions of Substrate (at least version 0.9.5014) with this new untether.

Please don't try to uninstall this package. If you want to remove your jailbreak, you need to restore your device with iTunes.

If you're curious, you can learn more about the name "Pangu" - "the first living being and the creator of all in some versions of Chinese mythology".

This 8.0-8.1 untether is nicknamed "Xuan-Yuan Sword", which refers to a powerful weapon in a series of video games based on Chinese mythology. See Xuan-Yuan Sword on Wikipedia.

This follows in the theme of the nickname of the 7.1-7.1.2 untether, which was "Pangu Axe", the powerful weapon used by the mythological Pangu to separate the earth and the sky.