Recently, we wrote a tutorial on how to downgrade from iOS 8.1.3 to iOS 8.1.2, and even suggested if you wanted to keep your jailbreak, you ought hurry up, because anytime Apple would stop sign iOS 8.1.2.
Well, the time has come, from now on, all you have updated any reason to iOS 8.1.3 or later (some beta), will not be able to downgrade to iOS 8.1.2, since jailbreak can no longer be performed for these people until further notice.
It was to be expected, Apple recently given some time for people to revert to a previous version of iOS and if possible do the jailbreak, but spends else, is that the release of iOS 8.2 is imminent, and Apple will afford to keep iOS 8.1.2, 8.1.3 and 8.2 at the same time, why else, have decided to stop signing the older version even if it means ending the chance to go back to benefit from this process .
Time you had, it must be said, now everything is in the hands of those who are working to find new exploits, although most likely not a jailbreak at least appears to the release of iOS 8.2 in March, because if now launched allow Apple fix the vulnerabilities in time for iOS 8.2 and would have wasted valuable exploits a minor update.
It is also possible (little but) they even wait for iOS 8.3, which as we know is already in beta or beta for developers, which means it should not be long before this is released, at most two months.
Apple maintains two versions to allow some continue to enjoy the jailbreak, and also to avoid fiascos like what happened with iOS 8.0.1, if so, by failing jailbreak for iOS 8.1.3 in March, along with the output of iOS 8.2, Apple should not take more than a couple of days to stop signing 8.1.3, doing in the latest versions already many confirming that such long periods that Apple is making to stop sign in the previous version would be to allow the downgrade.
If it does not do mean nothing, this more than anything are suspicions without official base, and whatever be the reason leading Apple to maintain two possible versions when restoring, it is appreciated as it is very support for the jailbreak community.
Returning to the main issue, that you have iOS 8.1.3, have currently impossible to perform the jailbreak, yes, as a new jailbreak is released, we will let you know instantly