- <xs:attribute name="version" type="xs:string"/>
- <xs:attribute name="name" type="xs:string"/>
- <xs:attribute name="urn" type="xs:string"/>
- <xs:attribute name="data" type="xs:string"/>
+ <xs:attribute name="version" type="xs:string" use="required"/>
+ <xs:attribute name="name" type="xs:string" use="required"/>
+ <xs:attribute name="urn" type="xs:string" use="required"/>
+ <xs:attribute name="data" type="xs:string" use="required"/>