In the most recent build there is an option to "post assignment notifications to this channel".
This allows me to create an assignment and notify only the relevant students. However, it doesn't bring up private channels as an option to post to. I regularly use private channels to preserve information about students' individual education plans.
Can private channels be added as an option to post to?
If Private Channels are not presented as an option, then they are not supported. Private Channels do not provide the same features you have in regular channels...as an example, you cannot add a Planner Plan to a Private Channel