The software blocks this exploit.
Apple recently released iOS 8.4.1 for all supported devices, it was expected that the new software might patch the exploit that TaiG uses in order to jailbreak the device. It brings the usual improvements and bug fixes as well as a security patch which ensures that TaiG can’t be used to jailbreak iOS 8.4.1.
Those who are on a previous version of iOS 8.4 and have it jailbroken using TaiG should steer clear of iOS 8.4.1, because updating to this latest version means that they are going to lose the jailbreak. TaiG will no longer work with the device so any and all customizations installed courtesy of the jailbreak will be removed for good.
iOS 8.4.1 patches the exploit that TaiG used for the jailbreak and unless the team can find a new one there will be no way to jailbreak this version or the ones that come after it. Thus the safe bet for people who need a jailbreak on their iOS device is to not upgrade to iOS 8.4.1 under any circumstances.
TaiG team has not yet said if they’re working on breaking iOS 8.4.1 as well which would eventually enable users to once again jailbreak their iOS devices.