Every time, the game of cat-and-mouse between Cupertino and jailbreakers goes like this. Apple releases a new version of iOS, patching existing jailbreak exploits. Jailbreakers poke and prod at the code for a few months, until they find a new exploit. They hold off on revealing the nature of this exploit to anyone for as long as humanly possible, lest Apple get wind of it and close the hole in a point release. Then, when the finished jailbreak is finally released, Apple’s programmers sniff out the exploit, patch it, and the whole game starts anew.
When Team Evasi0n released the iOS 7 jailbreak, then, it was only a matter of time before Apple fixed the exploit that allowed it to happen to begin with. Surprisingly, though, Cupertino did not patch Evasi0n in the developer betas of iOS 7.1… until now.