diff --git a/OneM2M_Types.ttcn b/OneM2M_Types.ttcn
index 2d4a784349fa1d57a01718b5bd4bfb50ade9b89a..1642857d81311fbd11f6b21cff5b673f93cb4048 100644
--- a/OneM2M_Types.ttcn
+++ b/OneM2M_Types.ttcn
@@ -6133,9 +6133,9 @@ type record EventNotificationCriteria
 	Timestamp expireAfter optional,
 	XSD.NonNegativeInteger sizeAbove optional,
 	XSD.PositiveInteger sizeBelow optional,
-	record length(0 .. 5) of Operation operationMonitor_list,
+	record length(0 .. 5) of Operation operationMonitor_list optional, //It should be optional
 	AttributeList_1 attribute optional,
-	record length(0 .. 5) of NotificationEventType notificationEventType_list,
+	record length(0 .. 5) of NotificationEventType notificationEventType_list optional, //It should be optional	
 	MissingData missingData optional,
 	FilterOperation filterOperation optional
 }