The current versions of the original Attendance app and the new Attendance2 app both run fine on iOS 6 as far as I can tell with my testing. Both should also run fine on the new iPhone 5 and new iPod Touch, but will have the black letterbox at the top and bottom of the screen. I have submitted a new version of Attendance2 (version 1.2.2) to Apple that should expand to use the entire screen. I want the original Attendance app to continue to run on iOS 4 so I am not certain if I will be able to update it so that it can use the entire screen of the new devices with taller screens. I need to read more about this so at least for now the original Attendance app will run letter boxed on the taller screens.
So far, I do not have any reports of of the data bug occurring in a file that was opened successfully at least once with version 1.2.1 of the Attendance2 app. While I cannot be certain it is fixed, if I do not receive any new reports in the next few weeks, that will be a good sign that version 1.2.1 seemed to fix the problem.