diff -urN asterisk-16.3.0.orig/res/res_pjsip/pjsip_message_filter.c asterisk-16.3.0/res/res_pjsip/pjsip_message_filter.c
--- asterisk-16.3.0.orig/res/res_pjsip/pjsip_message_filter.c	2019-04-04 16:49:57.000000000 +0200
+++ asterisk-16.3.0/res/res_pjsip/pjsip_message_filter.c	2019-06-18 14:46:57.784000000 +0200
@@ -341,6 +341,10 @@
 			}
 		}
 
+		/* set new sdp version */
+		ast_debug(5, "increment SDP version\n");
+		sdp->origin.version+=1;
+
 		pjsip_tx_data_invalidate_msg(tdata);
 	}