diff --git a/repository/src/main/resources/xsd/repositorytypes.xsd b/repository/src/main/resources/xsd/repositorytypes.xsd
index 4c39fd2..73bedf4 100644
--- a/repository/src/main/resources/xsd/repositorytypes.xsd
+++ b/repository/src/main/resources/xsd/repositorytypes.xsd
@@ -407,6 +407,13 @@
 				</xs:documentation>
 			</xs:annotation>
 		</xs:attribute>
+		<xs:attribute name="baseFieldId" type="fixr:id_t">
+			<xs:annotation>
+				<xs:documentation>Identifies a related field such as a non-encoded field related to an encoded field
+				or an alternate tag derived from encoding rules. However, this is not intended to represent semantic relationships.
+				</xs:documentation>
+			</xs:annotation>
+		</xs:attribute>
 		<xs:attributeGroup ref="fixr:fieldAttribGrp"/>
 		<xs:attribute name="instanceName" type="fixr:Name_t">
 			<xs:annotation>
@@ -491,6 +498,13 @@
 				</xs:documentation>
 			</xs:annotation>
 		</xs:attribute>
+		<xs:attribute name="baseFieldId" type="fixr:id_t">
+			<xs:annotation>
+				<xs:documentation>Identifies a related field such as a non-encoded field related to an encoded field
+				or an alternate tag derived from encoding rules. However, this is not intended to represent semantic relationships.
+				</xs:documentation>
+			</xs:annotation>
+		</xs:attribute>
 		<xs:attribute name="discriminatorId" type="fixr:id_t">
 			<xs:annotation>
 				<xs:documentation>Identifies a field used as a discriminator for this field's domain