If you have one of these cameras the upgrade 2.0.3 is available on the following link -

http://web.canon.jp/imaging/eosd/firm-e/eos5dmk2/firmware.html

In short the upgrade is more to do with videography than phototography changing the video frame rate to comply with TV production standards & enhancing the audio capabilities for professional use...but it may be of use to you.

If you want  more information simply visit: http://www.usa.canon.com/dlc/controller?act=GetArticleAct&articleID=3287