Differences between R5 and R6 server document fields

Is there some reference document or book that compares the differences between the R5 server document fields and the R6 server document fields (i.e., changes, additions, etc.)? Thanks.
Here is a good place to start: DominoSecurity.org -- click on Upgrading to R6.

Keep in mind that there is more to the R5 --> R6 upgrade than just some new fields in the server doc. There are new features and concepts as well.

This was first published in October 2003