Version der Versichertenkarte

Command 'tree' could not render: Invalid resource format: While building a POCO: Element 'url' must not repeat (at StructureDefinition.url[1])

Beispiel
    <extension url="http://fhir.de/StructureDefinition/gkv/version-egk">
        <valueString value="5.2.1" />
    </extension>