It appears that today's iOS 8.1.3 update Fixes many of the Exploits that were Used for the iOS 8 TaiG jailbreak, which worked up until iOS 8.1.2. The earlier Pangu Jailbreak was disabled with the iOS 8.1.1 update that was released on **vember 17.
At the current time, Apple is still signing iOS 8.1.2 so it's possible to downgrade from iOS 8.1.3 back to iOS 8.1.2 or upgrade to iOS 8.1.2 from an earlier version of iOS, but that could end at any time.
Released this morning, iOS 8.1.3 includes a range of bug Fixes including a repair for a lingering Wi-Fi issue, and it also reduces the amount of storage space required to perform an iOS update.