<xsd:group name="PositionIdAndVersion.model" >
  <xsd:annotation>
    <xsd:documentation xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en">A model group that includes a position ID and an optional version.</xsd:documentation>
  </xsd:annotation>
  <xsd:sequence>
    <xsd:element name="positionId" type="PositionId">
      <xsd:annotation>
        <xsd:documentation xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en">A version-independent identifier for the position, possibly based on trade identifier.</xsd:documentation>
      </xsd:annotation>
    </xsd:element>
    <xsd:element minOccurs="0" name="version" type="xsd:positiveInteger">
      <xsd:annotation>
        <xsd:documentation xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en">A version identifier. Version identifiers must be ascending, i.e. higher numbers imply newer versions. There is no requirement that version identifiers for a position be sequential or small, so for example timestamp-based version identifiers could be used.</xsd:documentation>
      </xsd:annotation>
    </xsd:element>
  </xsd:sequence>
</xsd:group>