I agree with the qualification to earlier editions train of thought, but maybe the poster was simply looking for the changes in D1.1 since 1998's edition.
How would one go about collecting that data, without buying the years in between(2000, 2002, and 2004) and copy checking each year for changes? (Not to mention that the edition for 2006 is about to come out)
The codes have been underlined where changes have occurred from the previous year, so you would need those years in between to find all the underlined texts to compare.
John Wright