Nope. Works fine for everyone else on the planet. Must just be you.
All sarcasm aside, your post really doesn't give much to go on. What version of software did you upgrade to? Which Apple TV version do you have? What content are you playing that you aren't getting surround sound from? (iTunes store content? homemade content?)
There were issues many versions ago with dolby digital content, but those were all with home conversions where the files weren't converted properly. It wasn't an Apple TV problem, it was a user problem.