I am sorry, I'm not sure if the prequel changes were mentioned before, but this page has interesting information about the BluRay changes of Episode I :
http://www.movie-censorship.com/report.php?ID=123195
Episode II
http://www.movie-censorship.com/report.php?ID=929191
Episode III
http://www.movie-censorship.com/report.php?ID=879092
Did they release for a very first time the THEATRICAL version on a digital video format ? Or have they done some audio changes ?
Plus the old trilogy, but that one was pretty much covered already
Episode IV
http://www.movie-censorship.com/report.php?ID=17542
Episode V
http://www.movie-censorship.com/report.php?ID=913207
Episode VI