Hi David, I am always very cautious when using msg_apply_changes() – e.g. there are some implications with Record-Route, afaik I do it this way: set_body("--outer\r\nContent-Type:application/sdp\r\n\r\n$rb" + "\r\n--outer\r\nContent-Type:application/vnd.3gpp.mcptt-info+xml\r\n\r\n" + "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\r\n" + ………… "\t</list>\r\n</resource-lists>" + "\r\n--outer--\r\n", "multipart/mixed;boundary=\"outer\""); Hope this helps, and sorry for slow reaction. I am scanning the mailing list in rather low frequency. Kr From: David Villasmil via sr-users &lt;sr-users(a)lists.kamailio.org&gt; Sent: Tuesday, March 5, 2024 7:08 PM To: Kamailio (SER) - Users Mailing List &lt;sr-users(a)lists.kamailio.org&gt; Cc: David Villasmil &lt;david.villasmil.work(a)gmail.com&gt; Subject: [SR-Users] Re: Add XML to INVITE Hello guys, Anyone on this? Regards, David Villasmil email: david.villasmil.work@gmail.com<mailto:david.villasmil.work@gmail.com> phone: +34669448337 On Sun, Mar 3, 2024 at 4:01 AM David Villasmil <david.villasmil.work@gmail.com<mailto:david.villasmil.work@gmail.com>> wrote: Hello guys, I'm trying to add an xml with a boundary to an outgoing INVITE. But if i do: set_body_multipart("$rb", "application/sdp", "delimiter"); msg_apply_changes(); append_body_part("$var(something)", "application/pidf+xml"); msg_apply_changes(); but kamailio adds the SDP, but NOT the second $var(something). If i switch them and add firs the var, and then the SDP. kamailio adds the contents of $var(something) but NOT the SDP.... point is it doesn't add the second append Thanks!!! Regards, David Villasmil email: david.villasmil.work@gmail.com<mailto:david.villasmil.work@gmail.com> phone: +34669448337