Before a child can be enrolled into kindergarten and go to kindergarten the child must be potty trained and be out of diapers.
If the child comes to kindergarten wearing diapers then the teacher will likely call the parents to have them pick them up.
Unless the child has incontinence issues and a medical need for wearing diapers then they must be potty trained and out of diapers before attending kindergarten and even preschool.
A preschooler can come to preschool wearing pull ups but they must be in the midst of potty training.
The preschooler might wear diapers but they must be able to use the potty.
But kindergarten children must be out of diapers before attending kindergarten and also other kids can be cruel and will make fun of your child if they come to school wearing diapers.