Hello, I have found a bug in function int_parse_status_line in file sip_parser.c. I was trying to use attended call transfer and trace status of the transfer via event subscription (pjsua-lib's on_call_transfer_status). But with each client I tested I was getting "Warning: received NOTIFY with invalid message/sipfrag content", even with pjsua. After few hours of debugging I found out the bug is in int_parse_status_line function. Suppose NOTIFY message "SIP/2.0 200 OK". On line 1570 parse_sip_version(scanner); would eat "SIP/2.0" from the scanner buffer. Then pj_scan_get( scanner, &pconst.pjsip_DIGIT_SPEC, &token); throws an exception because the scanner->currptr points to the whitespace in front of status code "200". I solved the problem by adding pj_scan_skip_whitespace: parse_sip_version(scanner); pj_scan_skip_whitespace(scanner); pj_scan_get( scanner, &pconst.pjsip_DIGIT_SPEC, &token); - Vali