What are the procedures when the information that the iris scanner has recorded is no longer valid?
The procedure will be that the student is blocked from entering the main entrance and required to report to the nurse's office within 45 seconds for mandatory drug testing.
Until the result of the drug test comes back from the lab, the nurse will issue the student with a pre-scanned animal eye in a jar to act as a temporary key. Also the kid in the wheelchair, the student with a bad case of cross-eyes, and the tenured Professor with macular degeneration, will be given their own permanent animal eye in a jar for accessibility reasons.
Everybody else, they will just do as they normally do when security gets too difficult, and they'll just leave the windows unlocked and the back doors propped open, just to make sure that they can come back into their building/dormitory, and/or to give a way for their own friends to get in (thus nullifying any kind of security against unknown outsiders).