Fix for horizontal line noise in high ISO images using flash, and some additional language choices.

http://www.dpreview.com/news/0412/04120701canoneos20dfw110.asp

Has anyone tried this firmward update yet? I have yet to update my 20D.

Works fine. I can't say it solved all of my horizontal banding issues at high ISOs, but IMO you might as well update to the latest firmware. It's painless to do so.