diff -ru pjproject-2.8/pjsip/src/pjsip-ua/sip_inv.c pjproject-2.8_mod/pjsip/src/pjsip-ua/sip_inv.c
--- pjproject-2.8/pjsip/src/pjsip-ua/sip_inv.c	2018-08-01 11:22:26.000000000 +0200
+++ pjproject-2.8_mod/pjsip/src/pjsip-ua/sip_inv.c	2018-11-26 14:21:54.000000000 +0100
@@ -4185,6 +4185,32 @@
 
 	    if (tsx->status_code != 100) {
 
+		if (inv->role == PJSIP_ROLE_UAC) {
+			pjsip_rx_data *rdata = e->body.tsx_state.src.rdata;
+		        pjsip_allow_hdr *allow = NULL;
+			pjsip_msg *msg = NULL;
+			msg = rdata->msg_info.msg;
+			if (msg) {
+			        allow = (pjsip_allow_hdr*) pjsip_msg_find_hdr(msg, PJSIP_H_ALLOW,
+                                 NULL);
+    			}
+			if (allow) {
+				unsigned i;
+				const pj_str_t STR_UPDATE = { "UPDATE", 6 };
+
+				for (i=0; i<allow->count; ++i) {
+				    if (pj_stricmp(&allow->values[i], &STR_UPDATE)==0)
+					break;
+				    }
+					if (i != allow->count) {
+					    /* UPDATE is present in Allow */
+					    inv->options |= PJSIP_INV_SUPPORT_UPDATE;
+					}
+
+    			}
+		}
+
+
 		if (dlg->remote.info->tag.slen)
 		    inv_set_state(inv, PJSIP_INV_STATE_EARLY, e);