While the new Yankee Stadium's fence distances have not changed significantly from the classic version, the heights of the fences are different. Whereas the previous ballpark had varying fence heights, ranging from 10 feet down to seven, with plenty of divergence in between, the new Yankee Stadium has a uniform height of eight feet. According to Greg Rybarczyk of Hit Tracker, adding a foot of height to a fence is equivalent to adding 0.84 feet of distance. This means that in some places you can tack on (or subtract) anywhere from 2.5 to 0.8 feet to the actual distance of the fences, if you're looking to compare their new digs to the old ones.
1dMike Vorkunov for REDEF