Thanks for the response.The idea is when we close a ticket in OSTicket then the response should be sent to main user and collaborators in one email. currently, sending email to main user and collaborators separately. e.g.-Ticket closer/post response e-mail should be delivered as-From: Support (OsTicket)To: Main UserCC: cc'd Users (Collaborators)Aside, for Incoming emails/Ticket, it's working fine and automatically adding/showing all cc's users in Ticket collaborators.