Surprisingly, Apple has released a new version of its mobile operating system in the last hour: iPhone OS 5.1.1. As you can guess, this is a minor release, determined only by small defects in the previous version. However, think twice before making a hasty update: If you are interested to jailbreak the situation is always a bit 'more complicated than when you are away from Cydia.
First, here is what are the difference between iPhone OS 5.1 and iPhone OS 5.1.1:
As you can see, the update does not introduce anything new: it is only a number of bug fixes.
Now for the part relating to the jailbreak. As we all know the jailbreakers, in most cases, Apple provides to fixare bugs on which the tools of leverage to allow jailbreaking to install third party applications.Currently it is not known exactly when the exploits of hackers that are working are only compatible with iPhone OS 5.1 or even on iPhone OS 5.1.1. What is certain is that the tethered jailbreak, long available on iPhone OS 5.1, is compatible with iPhone OS 5.1.1.
However, if you're interested in untethered jailbreak of nature, on which the hackers are working for some time, and that no one knows yet if and when it is released, you should not upgrade. If, however, prefer to install iPhone OS 5.1.1 , you can still use the tethered jailbreak by following this guide , remembering that it is only compatible with iPhone 3G, iPhone and iPad 4 of the first generation.