diff --git a/om-2.0.rdf b/om-2.0.rdf
index cf8e467..41f4c28 100644
--- a/om-2.0.rdf
+++ b/om-2.0.rdf
@@ -4,7 +4,7 @@
 
   <!-- Version 2.0 -->
 
-  <!-- (c) 2005-2023 Hajo Rijgersberg, Don Willems, Jan Top, Wageningen University and Research Centre, The Netherlands. This document is available under Creative Common License, version 4.0. You are free to Share — to copy, distribute, display, and perform the work and to Remix — to make derivative works; under the condition of Attribution: You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). The publisher does not accept any liability for the inaccuracies in this document. -->
+  <!-- (c) 2005-2024 Hajo Rijgersberg, Don Willems, Jan Top, Wageningen University and Research Centre, The Netherlands. This document is available under Creative Common License, version 4.0. You are free to Share — to copy, distribute, display, and perform the work and to Remix — to make derivative works; under the condition of Attribution: You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). The publisher does not accept any liability for the inaccuracies in this document. -->
 
   <!DOCTYPE rdf:RDF [
     <!ENTITY rdf     "http://www.w3.org/1999/02/22-rdf-syntax-ns#">
@@ -45,10 +45,10 @@
     <rdfs:label xml:lang="en">Ontology of units of Measure (OM)</rdfs:label>
     <rdfs:label xml:lang="nl">Ontologie van Maateenheden (OM)</rdfs:label>
     <rdfs:label xml:lang="ja">測定単位のオントロジー (OM)</rdfs:label>
-    <owl:versionInfo xml:lang="en">2.0.50</owl:versionInfo>
+    <owl:versionInfo xml:lang="en">2.0.51</owl:versionInfo>
     <!-- <dc:identifier>http://www.wurvoc.org/vocabularies/om-2.0/</dc:identifier> -->
     <dc:identifier>http://www.ontology-of-units-of-measure.org/vocabularies/om-2/</dc:identifier>
-    <dc:date>2023/10/10</dc:date>
+    <dc:date>2024/02/08</dc:date>
     <rdfs:comment xml:lang="en">The Ontology of units of Measure (OM) 2.0 models concepts and relations important to scientific research. It has a strong focus on units, quantities, measurements, and dimensions.</rdfs:comment>
     <rdfs:comment xml:lang="ja">測定単位のオントロジー (Ontology of units of Measure; OM) は，科学技術にとって重要な概念及び関係をモデル化する。OMは，単位・量・測定・次元に特に焦点を当てている。</rdfs:comment>
     <wv:logo>http://www.wurvoc.org/images/vocabularies/om-logo.jpg</wv:logo>
@@ -1581,9 +1581,9 @@
     <om:hasDimension rdf:resource="&om;length-Dimension"/>
   </om:Unit>
 
-  <owl:Thing rdf:about="&om;pathTravelledByLightInVacuumDuringATimeIntervalOf1299792458OfASecond">
+  <owl:NamedIndividual rdf:about="&om;pathTravelledByLightInVacuumDuringATimeIntervalOf1299792458OfASecond">
     <rdfs:label xml:lang="en">path travelled by light in vacuum during a time interval of 1/299 792 458 of a second</rdfs:label>
-  </owl:Thing>
+  </owl:NamedIndividual>
 
   <Length rdf:about="&om;lengthOfThePathTravelledByLightInVacuumDuringATimeIntervalOf1299792458OfASecond">
     <rdfs:label xml:lang="en">length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second</rdfs:label>
@@ -7186,9 +7186,9 @@
     <om:hasDimension rdf:resource="&om;time-Dimension"/>
   </om:Unit>
 
-  <owl:Thing rdf:about="&om;_9192631770PeriodsOfTheRadiationCorrespondingToTheTransitionBetweenTheTwoHyperfineLevelsOfTheGroundStateOfTheCesium133Atom">
+  <owl:NamedIndividual rdf:about="&om;_9192631770PeriodsOfTheRadiationCorrespondingToTheTransitionBetweenTheTwoHyperfineLevelsOfTheGroundStateOfTheCesium133Atom">
     <rdfs:label xml:lang="en">9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom</rdfs:label>
-  </owl:Thing>
+  </owl:NamedIndividual>
 
   <Duration rdf:about="&om;durationOf9192631770PeriodsOfTheRadiationCorrespondingToTheTransitionBetweenTheTwoHyperfineLevelsOfTheGroundStateOfTheCesium133Atom">
     <rdfs:label xml:lang="en">duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom</rdfs:label>
@@ -7914,9 +7914,9 @@
     <om:hasDimension rdf:resource="&om;mass-Dimension"/>
   </om:PrefixedUnit>
 
-  <owl:Thing rdf:about="&om;internationalPrototypeOfTheKilogram">
+  <owl:NamedIndividual rdf:about="&om;internationalPrototypeOfTheKilogram">
     <rdfs:label xml:lang="en">international prototype of the kilogram</rdfs:label>
-  </owl:Thing>
+  </owl:NamedIndividual>
 
   <Mass rdf:about="&om;massOfTheInternationalPrototypeOfTheKilogram">
     <rdfs:label xml:lang="en">mass of the international prototype of the kilogram</rdfs:label>
@@ -18370,9 +18370,9 @@
     <om:hasDimension rdf:resource="&om;thermodynamicTemperature-Dimension"/>
   </om:Unit>
 
-  <owl:Thing rdf:about="&om;triplePointOfWater">
+  <owl:NamedIndividual rdf:about="&om;triplePointOfWater">
     <rdfs:label xml:lang="en">triple point of water</rdfs:label>
-  </owl:Thing>
+  </owl:NamedIndividual>
 
   <ThermodynamicTemperature rdf:about="&om;_127316OfTheThermodynamicTemperatureOfTheTriplePointOfWater">
     <rdfs:label xml:lang="en">1/273.16 of the thermodynamic temperature of the triple point of water</rdfs:label>
@@ -28313,9 +28313,9 @@
     <om:hasDimension rdf:resource="&om;amountOfSubstance-Dimension"/>
   </om:Unit>
 
-  <owl:Thing rdf:about="&om;systemThatContainsAsManyElementaryEntitiesAsThereAreAtomsIn0.012KilogramOfCarbon12">
+  <owl:NamedIndividual rdf:about="&om;systemThatContainsAsManyElementaryEntitiesAsThereAreAtomsIn0.012KilogramOfCarbon12">
     <rdfs:label xml:lang="en">system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 122</rdfs:label>
-  </owl:Thing>
+  </owl:NamedIndividual>
 
   <AmountOfSubstance rdf:about="&om;amountOfSubstanceOfASystemThatContainsAsManyElementaryEntitiesAsThereAreAtomsIn0.012KilogramOfCarbon12">
     <rdfs:label xml:lang="en">amount of substance of a system that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12</rdfs:label>
@@ -39416,9 +39416,9 @@
     <rdf:type rdf:resource="&om;SingularUnit"/>
   </om:Unit>
 
-  <owl:Thing rdf:about="&om;oneBinaryDigit">
+  <owl:NamedIndividual rdf:about="&om;oneBinaryDigit">
     <rdfs:label xml:lang="en">one binary digit</rdfs:label>
-  </owl:Thing>
+  </owl:NamedIndividual>
 
   <InformationCapacity rdf:about="&om;informationCapacityOfOneBinaryDigit">
     <rdfs:label xml:lang="en">information capacity of one binary digit</rdfs:label>
@@ -42887,4 +42887,4 @@
   </bibo:Journal>
 
 
-</rdf:RDF>
\ No newline at end of file
+</rdf:RDF>