diff --git a/DER/RateDerivatives/RateDerivatives.rdf b/DER/RateDerivatives/RateDerivatives.rdf
index 7a9d9c446..db0fca113 100644
--- a/DER/RateDerivatives/RateDerivatives.rdf
+++ b/DER/RateDerivatives/RateDerivatives.rdf
@@ -51,11 +51,12 @@
 		<owl:imports rdf:resource="https://spec.edmcouncil.org/fibo/ontology/IND/InterestRates/InterestRates/"/>
 		<owl:imports rdf:resource="https://spec.edmcouncil.org/fibo/ontology/SEC/Securities/Baskets/"/>
 		<owl:imports rdf:resource="https://www.omg.org/spec/Commons/AnnotationVocabulary/"/>
-		<owl:versionIRI rdf:resource="https://spec.edmcouncil.org/fibo/ontology/DER/20240101/RateDerivatives/RateDerivatives/"/>
+		<owl:versionIRI rdf:resource="https://spec.edmcouncil.org/fibo/ontology/DER/20240901/RateDerivatives/RateDerivatives/"/>
 		<skos:changeNote>The https://spec.edmcouncil.org/fibo/ontology/DER/20180801/RateDerivatives/RateDerivatives.rdf version of this ontology was extended to include foreign exchange rates, forward rate agreements, and revise definitions to be unambiguous and ISO 704 compliant.</skos:changeNote>
 		<skos:changeNote>The https://spec.edmcouncil.org/fibo/ontology/DER/20201201/RateDerivatives/RateDerivatives.rdf version of this ontology was modified to eliminate the dependency on NonPhysicalUnderlier, which was redundant.</skos:changeNote>
 		<skos:changeNote>The https://spec.edmcouncil.org/fibo/ontology/DER/20210801/RateDerivatives/RateDerivatives.rdf version of this ontology was modified to use the Commons Ontology Library (Commons) Annotation Vocabulary rather than the OMG&apos;s Specification Metadata vocabulary, to move the definition of an underlier and the related property, has underlier, to financial instruments so that these concepts are also available for use in relation to pool-backed securities.</skos:changeNote>
 		<skos:changeNote>The https://spec.edmcouncil.org/fibo/ontology/DER/20230201/RateDerivatives/RateDerivatives.rdf version of this ontology was modified to replace content that is now available in the OMG Commons Ontology Library (Commons) v1.1 (FND-380).</skos:changeNote>
+		<skos:changeNote>The https://spec.edmcouncil.org/fibo/ontology/DER/20240101/RateDerivatives/RateDerivatives.rdf version of this ontology was modified to deprecate ForeignExchangeRateObservable after other changes that eliminated its usage in currency derivatives and made it obsolete (DER-143).</skos:changeNote>
 		<fibo-fnd-utl-av:hasMaturityLevel rdf:resource="&fibo-fnd-utl-av;Release"/>
 		<cmns-av:copyright>Copyright (c) 2016-2024 EDM Council, Inc.</cmns-av:copyright>
 		<cmns-av:copyright>Copyright (c) 2016-2024 Object Management Group, Inc.</cmns-av:copyright>
@@ -87,15 +88,8 @@
 	</owl:Class>
 	
 	<owl:Class rdf:about="&fibo-der-rtd-rtd;ForeignExchangeRateObservable">
-		<rdfs:subClassOf rdf:resource="&fibo-der-rtd-rtd;RateBasedObservable"/>
-		<rdfs:subClassOf>
-			<owl:Restriction>
-				<owl:onProperty rdf:resource="&cmns-rlcmp;isPlayedBy"/>
-				<owl:someValuesFrom rdf:resource="&fibo-ind-fx-fx;QuotedExchangeRate"/>
-			</owl:Restriction>
-		</rdfs:subClassOf>
-		<rdfs:label xml:lang="en">foreign exchange rate observable</rdfs:label>
-		<skos:definition>rate-based observable that is an exchange rate, typically a quoted exchange rate</skos:definition>
+		<owl:deprecated rdf:datatype="&xsd;boolean">true</owl:deprecated>
+		<owl:equivalentClass rdf:resource="&fibo-der-rtd-rtd;RateBasedObservable"/>
 	</owl:Class>
 	
 	<owl:Class rdf:about="&fibo-der-rtd-rtd;ForwardRateAgreement">