my son is no where near that age yet... but my step daughter is nearly 6. she still had occasional accident at 4, reminding her to go pee honestly helped. like giving her times, at lunch, or snack time etc
The school shouldn't be making an issue of it. It could be the anxiety of using a new toilet, there is no harm in the school reminding him for the first few weeks. I've helped to toilet train lots of children and we were often reminding them.
My stepdaughter is 6 and hasn’t had an accident in maybe* 5 months. She had several accidents last year in kindergarten where her teacher required all students bring an extra change of clothes just in case. Not sure I have tips but just know the school is overreacting. Yes children need to learn to potty train but having an occasional accident at 4 is common.
I will say we remind her often. We will pause tv shows, ask her to go try, make sure she goes regularly before we leave the house, before bed, before new activities. Sometimes she will whine that she doesn’t need to go but I can count on 1 hand how many times she didn’t need to go when asked.
My son is 5 and about to start kindergarten and I've just finally got him to stop peeing his pants on a regular basis. I have no advice.