I upgraded my already jailbroken iphone 4s from 5.0.1 to 6.1 then jailbroke it again using Evasi0n. Had been holding off waiting for a new jailbreak which was timely as I was finding more and more apps weren't backwards compatible to 5.0.1.
Was simples and the only issue to date is the Apple wx app didn't work for me. I see there is a new release of the jailbreak so I will probably do that again at some stage and sort that out.
As with all of these things just take a backup prior to jailbreaking and you can always go back and reinstall if needs be.
Last edited by MCDU2; 8th February 2013 at 10:01.