jerrylanejohns Last message is the most recent message received from the ticket owner or one of the collaborators.
Last response is the last message entered by an agent.
Last Update is the time of the last message received from the owner or a collaborator.
Key points really are the difference between last message and last response (user vs agent) and that 'last updated' isn't modified when an agent replies,
You can add the Last Updated time into your templates with the %{ticket.last_updated.x} variable (replace x with the format you want it in, such as 'long', 'short', etc...)