diff --git a/OneM2M_Types.ttcn b/OneM2M_Types.ttcn
index 515230fbabe8a804fc88e00ca19ffbedf78570da..c3119e166f0186125ea15ad84933430455c2747d 100644
--- a/OneM2M_Types.ttcn
+++ b/OneM2M_Types.ttcn
@@ -4901,7 +4901,7 @@ type record MgmtCmd
 			ExecInstance execInstance,
 			Subscription subscription
 		} choice_list
-	} choice
+	} choice optional
 }
 with {
   variant "name as uncapitalized";
@@ -5120,7 +5120,7 @@ type record Notification_1
 	} notificationEvent optional,
 	XSD.Boolean verificationRequest optional,
 	XSD.Boolean subscriptionDeletion optional,
-	XSD.AnyURI subscriptionReference optional,
+	XSD.AnyURI subscriptionReference,
 	XSD.ID creator optional,
 	XSD.AnyURI notificationForwardingURI optional,
 	XSD.ID notificationTarget optional,