diff --git a/hlr/HLR_Tests.ttcn b/hlr/HLR_Tests.ttcn
index 8b21626..90a00bf 100644
--- a/hlr/HLR_Tests.ttcn
+++ b/hlr/HLR_Tests.ttcn
@@ -480,6 +480,10 @@
 		sub.msisdn := new_msisdn;
 		setverdict(pass);
 		}
+	[] GSUP.receive(tr_GSUP_ISD_REQ(sub.imsi, sub.msisdn)) {
+		log("received ISD req with old MSISDN");
+		setverdict(fail);
+		}
 	[] GSUP.receive { repeat; }
 	[] T.timeout {
 		setverdict(fail, "Timeout waiting for ISD.req");