diff --git a/miniupnpd/Changelog.txt b/miniupnpd/Changelog.txt
index eb908e3..a010c37 100644
--- a/miniupnpd/Changelog.txt
+++ b/miniupnpd/Changelog.txt
@@ -1,6 +1,7 @@
 $Id: Changelog.txt,v 1.421 2016/02/12 12:34:37 nanard Exp $
 
 2016/02/12:
+  return error 729 - ConflictWithOtherMechanisms if IGD v2 is enabled.
   add iptc_init() check in iptcrdr.c/init_redirect()
 
 2016/02/11:
diff --git a/miniupnpd/upnpredirect.c b/miniupnpd/upnpredirect.c
index 7e3a6cb..4e1c037 100644
--- a/miniupnpd/upnpredirect.c
+++ b/miniupnpd/upnpredirect.c
@@ -1,7 +1,7 @@
-/* $Id: upnpredirect.c,v 1.85 2014/12/09 09:17:54 nanard Exp $ */
+/* $Id: upnpredirect.c,v 1.90 2016/02/12 12:59:41 nanard Exp $ */
 /* MiniUPnP project
  * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
- * (c) 2006-2014 Thomas Bernard
+ * (c) 2006-2016 Thomas Bernard
  * This software is subject to the conditions detailed
  * in the LICENCE file provided within the distribution */
 
@@ -254,6 +254,7 @@ int reload_from_lease_file()
  *          -1 failed to redirect
  *          -2 already redirected
  *          -3 permission check failed
+ *          -4 already redirected (other mechanism)
  */
 int
 upnp_redirect(const char * rhost, unsigned short eport,
@@ -299,7 +300,7 @@ upnp_redirect(const char * rhost, unsigned short eport,
 	} else if (port_in_use(ext_if_name, eport, proto, iaddr, iport) > 0) {
 		syslog(LOG_INFO, "port %hu protocol %s already in use",
 		       eport, protocol);
-		return -2;
+		return -4;
 #endif /* CHECK_PORTINUSE */
 	} else {
 		timestamp = (leaseduration > 0) ? time(NULL) + leaseduration : 0;
diff --git a/miniupnpd/upnpsoap.c b/miniupnpd/upnpsoap.c
index 1eb64e6..759bde9 100644
--- a/miniupnpd/upnpsoap.c
+++ b/miniupnpd/upnpsoap.c
@@ -1,7 +1,7 @@
-/* $Id: upnpsoap.c,v 1.142 2015/12/15 11:12:37 nanard Exp $ */
+/* $Id: upnpsoap.c,v 1.144 2016/02/12 12:35:03 nanard Exp $ */
 /* MiniUPnP project
  * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
- * (c) 2006-2015 Thomas Bernard
+ * (c) 2006-2016 Thomas Bernard
  * This software is subject to the conditions detailed
  * in the LICENCE file provided within the distribution */
 
@@ -474,7 +474,7 @@ AddPortMapping(struct upnphttp * h, const char * action, const char * ns)
              ExternalPort must be a wildcard and cannot be a specific port
              value (deprecated in IGD v2)
      * 728 - NoPortMapsAvailable
-             There are not enough free prots available to complete the mapping
+             There are not enough free ports available to complete the mapping
              (added in IGD v2)
 	 * 729 - ConflictWithOtherMechanisms (added in IGD v2) */
 	switch(r)
@@ -484,6 +484,11 @@ AddPortMapping(struct upnphttp * h, const char * action, const char * ns)
 		                   action, ns/*SERVICE_TYPE_WANIPC*/);
 		BuildSendAndCloseSoapResp(h, body, bodylen);
 		break;
+	case -4:
+#ifdef IGD_V2
+		SoapError(h, 729, "ConflictWithOtherMechanisms");
+		break;
+#endif /* IGD_V2 */
 	case -2:	/* already redirected */
 	case -3:	/* not permitted */
 		SoapError(h, 718, "ConflictInMappingEntry");