Hi, I've been using the default cfg file as a starting point and added my stuff on top. But I don't think I understand the use of t_newtran/t_release and when they should be used. Read the documentation but still not clear. For example, for presence: t_newtran is called before handle_publish/subscribe and t_release called afterwards. And in route[LOCATION], t_newtran is called before sending 4xx responses. Could someone help explain please what they do and when they should be used please? Thank you! Yufei -- Yufei Tao Red Embedded This E-mail and any attachments hereto are strictly confidential and intended solely for the addressee. If you are not the intended addressee please notify the sender by return and delete the message. You must not disclose, forward or copy this E-mail or attachments to any third party without the prior consent of the sender. Red Embedded Design, Company Number 06688253 Registered in England: The Waterfront, Salts Mill Rd, Saltaire, BD17 7EZ