There is no changes. They released at the same time on a limited run of digital projectors. IMAX ATOC released well after the theatrical release (so minor changes would entice those that have seen it to come back out), is on a totally different format (being the screen is almost square) and there is only one IMAX theatre per location necessitating shorter run time to show the 3 other films that have a daily run in the theatre. I saw the digital version at Camelot in Greenville, SC and it was mind-boggling on a 60' screen with a Digital Christie projector...stark difference. I saw Batman at IMAX last week and the difference was not nearly as stark. Of course Star Wars is mostly CG and therefore digital at inception vs. film being converted over to digital. Even still I'd take Camelot over Imax any day...of course this is why I am going to see War of the Worlds there tonight and I will drive over 2 hours to do it. (I drove 3.5 to Charleston to see Batman at IMAX).