I was trying to track down the cause of a problem with a clients database behaving differently between R5.0.4 and R5.0.7a (web view form formula oddities), and thought I'd check the release notes to see if anything had changed / been fixed.
Except they've gone!
"Oh just one more thing Mr IBM. I noticed you've got all the release notes lined up in a row, R4, R6, R7 but I don't quite understand why there is no R5. Perhaps you could explain that to me sir?"