They still have a paper planner. :) But checking the app each morning is mandatory. And in my son's case, there are changes every couple of days.
I'm not sure that was much better than just telling the students in advance when you know a schedule will change and sending them to the library to study or etc.
If this is your blog please add "Show HN: " to the title here.
> you've made something that other people can play with. HN users can try it out, give you feedback, and ask questions in the thread. [1]
but afaik nothing in the guidelines [2] requires it.