Is your suggestion related to a problem? Please describe.
For some rooms, I want the other room members to know which messages I have seen; for other rooms, I do not want the members to know when I have (or not yet have) seen a message. It looks like I currently don't have that choice.
Describe the solution you'd like
I would like to be able to choose per room whether the other room members can see up to which message I have read the conversation.
A bonus feature would be a choice of default behaviour for newly joined rooms.