What regulations changed between the 2004 publication 587 and the 2009 publication 587?

Here's a link to the 2004 version:
http://www.irs.gov/pub/irs-prior/p587--2004.pdf

And the 2009 version:
Publication 587 (2009), Business Use of Your Home

There doesn't seem to be much difference, but it would help to know what you are specifically interested in.