Do I need the newest ATV software?

I have a macbook pro that I bought in June 2011 and the ATV 2. I installed mountain lion today and see the airplay icon in the bar on top, but am not able to stream my computer to the screen. My ATV is jailbroken and I do not want to lose the jb, so I do not have the newest software. Is that needed in order to get mirroring?

The ATV apparently requires iOS 5.1 beta 2 or later for this to work.
How to Use AirPlay Mirroring on a Mac with OS X 10.8 Mountain Lion

ok, thanks a lot

I upgraded to the newest software and re-jailbroke and the mirroring works perfectly. The only odd thing is that when I exit mirroring, I have no sound until I go into the display preferences and uncheck airplay and re-check internal speakers.