Hi, I got an assertion failure about the 100rel module, which I indeed do not have initialized and do not want to use, when calling pjsip_inv_create_uac. It contains the following lines: 662 /* Create 100rel handler */ 663 pjsip_100rel_attach(inv); I think maybe the options need to be checked to see if the user even requested use of the 100rel functionality. Ruud Klaver AG Projects