There's an avalanche of character tweakings from the amount of damage done to frame reductions. This Version 2013 update is entirely free from Capcom. It's a system change KO.
Frankly there are way too many alterations to be listed here, so if you want to peruse the changelog you'll need to visitfor the full stat heavy details.
The Version 2013 update for Street Fighter x Tekken is expected to release by the end of 2012 for all platforms.