diff --git a/v3_30_0/CDT-notification-v3_30_0.xsd b/v3_30_0/CDT-notification-v3_30_0.xsd
index 1fc4eb53a611a12a9d30fc33f6f699a293486ec1..233d3c3df24d785a548d431ec3bcdd0f2c67cb01 100644
--- a/v3_30_0/CDT-notification-v3_30_0.xsd
+++ b/v3_30_0/CDT-notification-v3_30_0.xsd
@@ -58,7 +58,7 @@ oneM2M EXPRESSLY ADVISES ANY AND ALL USE OF OR RELIANCE UPON THIS INFORMATION PR
                         </xs:element>                      
                     <xs:element name="verificationRequest" type="xs:boolean" minOccurs="0"/>
                     <xs:element name="subscriptionDeletion" type="xs:boolean" minOccurs="0"/>
-                    <xs:element name="subscriptionReference" type="xs:anyURI" minOccurs="0"/>
+                    <xs:element name="subscriptionReference" type="xs:anyURI" />
                     <xs:element name="creator" type="m2m:ID" minOccurs="0"/>
                     <xs:element name="notificationForwardingURI" type="xs:anyURI" minOccurs="0"/>
                     <xs:element name="notificationTarget" type="m2m:ID" minOccurs="0"/>