You can enable popup warning messages if a pet is missing or has expired vaccines.
In File, System Options. For every module except Petsitting, check the box to Show vaccine warnings. This must be done on every computer.
Now you will get a popup message when you scroll through the days on the schedule.
You can also turn on the Vaccine column on the schedule. If the box is checked, that pet has missing or expired vaccines.
You can disable/enable this column for Boarding, Grooming and Daycare. Training and Special Services has this column and there isn't an option not to show it.
You can also turn on vaccine warnings if you open the pet card or add an appointment.
In File, System Options, Global tab, check the box to Show vaccination warnings.
You will get this message when opening the pet card or clicking to add an appointment.