diff --git a/v3_15_0/CDT-notification-v3_15_0.xsd b/v3_15_0/CDT-notification-v3_15_0.xsd
index 95fd91511115e73f104890fa9b8d200279125235..2273f9b8ef4aa3a7539e294b0f307fa6407358cc 100644
--- a/v3_15_0/CDT-notification-v3_15_0.xsd
+++ b/v3_15_0/CDT-notification-v3_15_0.xsd
@@ -74,8 +74,8 @@ oneM2M EXPRESSLY ADVISES ANY AND ALL USE OF OR RELIANCE UPON THIS INFORMATION PR
                         </xs:element>   
                     <xs:element name="AERegistrationPointChange" type="xs:boolean" minOccurs="0"/>
                     <xs:element name="AEReferenceIDChange" type="xs:boolean" minOccurs="0"/>
-                    <xs:element name="trackingID1" type="m2m:ID" minOccurs="1"/>
-                    <xs:element name="trackingID2" type="m2m:ID" minOccurs="1"/>
+                    <xs:element name="trackingID1" type="m2m:ID" minOccurs="0"/>
+                    <xs:element name="trackingID2" type="m2m:ID" minOccurs="0"/>
                     
                 </xs:sequence>
         </xs:complexType>