You from Vietnam have 1 small request. Bind the minimum number of lessons to 2 for all teachers, is it possible to add all teachers and subtract special cases?
Sadly you can't do that right now, but there is a trick possible for those teachers: Just give them one (or more) pseudo activity. So only a activity with a teacher, but no students and no room. (If it is conflicting with a teacher home room, then add a pseudo teacher name also, since teacher hoom rooms are not used if there are 2 teachers in an activity.
Can you change it in the upcoming official version?
No, it is too complicated, sorry. It was not thought of from the start, and now it is too difficult to change.