Compulsory Education Act Article 8

Before the end of May each year, primary schools shall compile and submit a list of students due to graduate to the competent education authority for further distribution. Before July 15, the nationals listed shall be notified to enroll in a junior high school in their school district.
中文原文 強迫入學條例第8條
國民小學應於每年五月底前,造具當年度畢業生名冊,報請主管教育行政機關辦理分發,並於七月十五日前按學區通知入國民中學。

English translation for reference only; the Chinese text prevails. Not legal advice.