Just curious, the app and website seem to have all the bat man series, excluding the knight fall series. Any reason why?
Unless Im misunderstanding what you are talking about, it has Knightfall. Knightfall wasn’t a its own series, it was a story that took place across multiple titles featuring Batman. If you go to Storylines, you should be able to find Batman: Knightfall, Batman: Knightquest, and Batman: KnightsEnd there. Those aren’t complete, but they’re close enough.
If you look up a reading order online, you’ll see that it was all told in various series that were running at the time, and you can hop around using that. I tend not to use DCU’s reading orders all that often, but when I have, those have generally been fairly complete and accurate too.