I have a parent who has an iPhone. Her PowerSchool mobile app is still pointing to the 2019-2020 school year. She is not receiving any option to change school years. Everything is setup correctly in our PowerSchool SIS. Is there something wrong with the mobile app?
If it is just one parent, I would recommend they delete the app and reinstall. I run the mobile app on my phone and iPad to monitor a student in each grade level to make sure everything is working. It sounds like that parent's app is not refreshing.