Yes, via a scheduled job that runs on the server. It looks for messages that are still unread about 10 minutes after they were posted: for a customer message it emails your kitchen address (unread message admin template, linking to the proposal's Messages tab) and notifies any proposal team members; for an admin message it emails each attached customer (new proposal unread message customer template) with a link to /proposals/{id}#messages. If the recipient opens the thread and marks it as read within that window, no email is sent. Because the check targets a narrow time window, the job must run every minute on the server for notifications to be reliable.