Hello,

On ODOO V11 for example, an automated action on the "mail.message" model. Check in the application domain that the author is not an internal user and that the document template is helpdesk.ticket. And in Python code, you have to put for example:

if record:

tickets = env ['helpdesk.ticket']. search ([('message_ids', '=', record.id)])

for ticket in tickets:

ticket.write ({'kanban_state': 'done'})