diff --git a/xsd/netex_part_1/part1_ifopt/netex_ifopt_site_version.xsd b/xsd/netex_part_1/part1_ifopt/netex_ifopt_site_version.xsd
index 526a8bb5d..04f0c69aa 100644
--- a/xsd/netex_part_1/part1_ifopt/netex_ifopt_site_version.xsd
+++ b/xsd/netex_part_1/part1_ifopt/netex_ifopt_site_version.xsd
@@ -549,6 +549,11 @@ Rail transport, Roads and Road transport
 				<xsd:sequence>
 					<xsd:group ref="LevelGroup"/>
 				</xsd:sequence>
+				<xsd:attribute name="order" type="xsd:integer">
+					<xsd:annotation>
+						<xsd:documentation>Order of Levels. The levels numbers are not absolute, but only give a relative order.</xsd:documentation>
+					</xsd:annotation>
+				</xsd:attribute>				
 			</xsd:extension>
 		</xsd:complexContent>
 	</xsd:complexType>