An update to the EVO 4G hit the internet recently. As always the people over at XDA have gotten their hands on the software, rooted it, and are currently in the middle of the investigative process to see what has been changed.
According to joeykrim the update included changes to the hboot, Recovery.img, kernel, and many of the .jar files within the overall framework. The update is new and may not yet be ready for the masses so it may be a smart idea to hold off unless you're feeling adventurous and want to experience for your self and even doing some investigative work.
[Via XDA Forums]