The Dev-Team has just updated their post about the new redsn0w jailbreak (which allows the ability to jailbreak iOS 4.2.1) saying that you should be on version 10.1 of iTunes to have the best jailbreaking results. They just added the disclaimer to the bottom of their current post.
Dev-Team Says Upgrade to iTunes 10.1 for Best Jailbreaking Results
November 23, 2010 by