At the moment, there is no way to reference an external emails subject response to a ticket, to be able gather or parse information from it, such as an external ticket ID - which can help when communicating outbound with other helpdesks.

In this scenario:

• A ticket is created in Deskpro with subject "Foo 123"
• An email is triggered to an external mail system or helpdesk, with the subject set in Deskpro "Foo 123"
• The external helpdesk responds with an email, however the subject has been changed to "Bar 456: Foo123" as the external helpdesk has prepended their own ticket referencing system.
• Deskpro is able to detect this change, and correctly adds the response into the Deskpro ticket. It references an embedded unique bit of code in the mail body to do this.
• A Deskpro agent responses, however the subject remains "Foo 123"
• The external service desk does not recognise this new email, and creates a new ticket in the external system.

This does not necessarily disrupt the ticket Deskpro side, however it causes new tickets to be created in the external service desk.

The solution would be some sort of trigger, regex and variable to parse the NEW incoming subject "Bar456: Foo123" and set the Deskpro  subject to this, as to work better with the external service desk. At the moment, no variable is available in the system outside of {{ ticket.subject }} or {{ ticket.id}} which refer only to the data Deskpro side, the system does not grab the subject of the response email.