do not send 501 to out of dialog BYE, but rather 481.

NEWS

 linphone-3.7...??
+	Liblinphone level improvements thanks to belle-sip new SIP stack:
 	* multiple SIP transports simualtaneously now allowed
 	* IP dual stack: can use IPv6 and IPv4 simultaneously
 	* fully asynchronous behavior: no more lengthly DNS or connections 
@@ -7,8 +8,8 @@ linphone-3.7...??
 	* better management of network disconnections
 	* SIP/TLS handled through lightweighted polarssl library (instead of openssl)
 	* SIP transaction state machines improved (RFC6026)
-	* Privacy API
-	* Full support of rich presence
+	* Privacy API (RFC3323, RFC3325)
+	* Full support of rich presence in (RFC4480)
 
 
 linphone-3.6.1 -- June 17, 2013

coreapi/bellesip_sal/sal_impl.c

@@ -208,6 +208,10 @@ static void process_request_event(void *sal, const belle_sip_request_event_t *ev
 		resp=belle_sip_response_create_from_request(req,481);/*INFO out of call dialogs are not allowed*/
 		belle_sip_provider_send_response(((Sal*)sal)->prov,resp);
 		return;
+	}else if (strcmp("BYE",method)==0) {
+		resp=belle_sip_response_create_from_request(req,481);/*out of dialog BYE */
+		belle_sip_provider_send_response(((Sal*)sal)->prov,resp);
+		return;
 	}else {
 		ms_error("sal process_request_event not implemented yet for method [%s]",belle_sip_request_get_method(req));
 		resp=belle_sip_response_create_from_request(req,501);