diff --git a/xsd/siri_model/siri_situation-v2.0.xsd b/xsd/siri_model/siri_situation-v2.0.xsd
index ef5fa89a..519c2e78 100644
--- a/xsd/siri_model/siri_situation-v2.0.xsd
+++ b/xsd/siri_model/siri_situation-v2.0.xsd
@@ -586,7 +586,7 @@ Rail transport, Roads and road transport
      <xsd:restriction base="VerificationStatusEnumeration"/>
     </xsd:simpleType>
    </xsd:element>
-   <xsd:element name="Progress" type="WorkflowStatusEnumeration" default="open">
+   <xsd:element name="Progress" type="WorkflowStatusEnumeration" default="open" minOccurs="0">
     <xsd:annotation>
      <xsd:documentation>ProgressStatus. One of a specified set of overall processing states assigned to SITUATION. For example, 'Draft' for not yet published; 'Published' for live SITUATIONs; 'Closed' indicates a completed SITUATION.</xsd:documentation>
     </xsd:annotation>