Collaboration
The course conversation, inside the course
Channels per course and per subject, threads, attachments and moderation, with a history that does not vanish when you change phones.
In short
One channel per course
Created on its own when the school year opens. Nobody has to manage groups by hand.
Threads, not an endless list
Each topic has its thread, so a question from October is still findable in March.
Real moderation
An inappropriate message is withdrawn, and it is on record who withdrew it and why.
In detail
Who can write and who can only read
It depends on the channel. In the school announcements channel the administration writes; in a course channel, its teacher and its students.
The history does not live on a phone
Changing your number or your device does not erase what was said. That is the difference from a messaging group, and usually the one people notice most.
Attachments with a limit and a checked type
The server inspects the file before storing it, not just its extension.