iOS 9 has just been released and many students/parents may want to update their iPads. While the DLSZ E-Reader App and the e-books are already compatible with iOS 9, the school still recommends all students, especially those with iPad4 and iPad Air, to hold-off updating.
Some students with the models above have experienced iOS9 update issues, causing their iPads to display a blank, unresponsive white screen with the text “slide to upgrade” written at the bottom.
Currently, this problem can only be remedied with a full restoration of iOS 8.4.1. All data on the iPad will be erased with this procedure.
Several other users have reported the same bug as relayed in the Apple Forums. See the link: https://discussions.apple.com/thread/7218562?start=0&tstart=0
