diff --git a/src/metaschema/oscal_assessment-common_metaschema.xml b/src/metaschema/oscal_assessment-common_metaschema.xml
index b2d2543690..59ee135aaf 100644
--- a/src/metaschema/oscal_assessment-common_metaschema.xml
+++ b/src/metaschema/oscal_assessment-common_metaschema.xml
@@ -62,16 +62,16 @@
          <field ref="remarks" in-xml="WITH_WRAPPER" min-occurs="0" max-occurs="1"/>
       </model>
       <constraint>
-         <allowed-values id="oscal-assessment-objective-types" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+         <allowed-values id="oscal-assessment-objective-types" target="part[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             <enum value="objective" deprecated="1.0.1">**(deprecated)** Use 'assessment-objective' instead.</enum>
             <enum value="assessment" deprecated="1.0.1">**(deprecated)** Use 'assessment-method' instead.</enum>
             <enum value="assessment-objective">The part defines an assessment objective.</enum>
             <enum value="assessment-method">The part defines an assessment method.</enum>
          </allowed-values>
-         <has-cardinality id="oscal-assessment-objective-cardinality" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('objective','assessment-objective')]" max-occurs="1" />
-         <has-cardinality id="oscal-assessment-method-cardinality" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('assessment','assessment-method')]/prop[has-oscal-namespace(('http://csrc.nist.gov/ns/oscal','http://csrc.nist.gov/ns/rmf')) and @name='method']" min-occurs="1" max-occurs="1" />
-         <has-cardinality id="oscal-assessment-objects-cardinality" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('assessment','assessment-method')]/part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('objects','assessment-objects')]" min-occurs="1" max-occurs="1" />
-         <has-cardinality id="oscal-assessment-method-id-cardinality" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('objective','assessment-objective')]/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='method-id']" min-occurs="1" />
+         <has-cardinality id="oscal-assessment-objective-cardinality" target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('objective','assessment-objective')]" max-occurs="1" />
+         <has-cardinality id="oscal-assessment-method-cardinality" target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('assessment','assessment-method')]/prop[has-oscal-namespace(('http://csrc.nist.gov/ns/oscal','http://csrc.nist.gov/ns/rmf')) and @name='method']" min-occurs="1" max-occurs="1" />
+         <has-cardinality id="oscal-assessment-objects-cardinality" target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('assessment','assessment-method')]/part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('objects','assessment-objects')]" min-occurs="1" max-occurs="1" />
+         <has-cardinality id="oscal-assessment-method-id-cardinality" target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('objective','assessment-objective')]/prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='method-id']" min-occurs="1" />
       </constraint>
    </define-assembly>
    <define-assembly name="assessment-method">
@@ -183,11 +183,11 @@
       </model>
       <constraint>
          <!-- TODO: Dave to double-check constraints here -->
-         <allowed-values id="oscal-activity-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+         <allowed-values id="oscal-activity-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             <enum value="method">The assessment method to use. This typically appears on parts with the name "assessment".</enum>
          </allowed-values>
-         <has-cardinality id="oscal-activity-type-cardinality" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='method']" min-occurs="1"/>
-         <allowed-values id="oscal-activity-type-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='method']/@value">
+         <has-cardinality id="oscal-activity-type-cardinality" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='method']" min-occurs="1"/>
+         <allowed-values id="oscal-activity-type-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='method']/@value">
             <enum value="INTERVIEW">The process of holding discussions with individuals or groups of individuals within an organization to once again, facilitate assessor understanding, achieve clarification, or obtain evidence.</enum>
             <enum value="EXAMINE">The process of reviewing, inspecting, observing, studying, or analyzing one or more assessment objects (i.e., specifications, mechanisms, or activities).</enum>
             <enum value="TEST">The process of exercising one or more assessment objects (i.e., activities or mechanisms) under specified conditions to compare actual with expected behavior.</enum>
@@ -1274,10 +1274,10 @@
                      <field ref="remarks" in-xml="WITH_WRAPPER" min-occurs="0" max-occurs="1"/>
                   </model>
                   <constraint>
-                     <allowed-values id="oscal-risk-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                     <allowed-values id="oscal-risk-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="type">The type of remediation tracking entry. Can be multi-valued.</enum>
                      </allowed-values>
-                     <allowed-values id="oscal-risk-prop-type-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='type']/@value" allow-other="yes">
+                     <allowed-values id="oscal-risk-prop-type-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='type']/@value" allow-other="yes">
                         <enum value="vendor-check-in">Contacted vendor to determine the status of a pending fix to a known vulnerability.</enum>
                         <enum value="status-update">Information related to the current state of response to this risk.</enum>
                         <enum value="milestone-complete">A significant step in the response plan has been achieved.</enum>
@@ -1308,13 +1308,13 @@
       </model>
       <constraint>
          <!-- REVIEW THIS -->
-         <allowed-values id="oscal-risk-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+         <allowed-values id="oscal-risk-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             <enum value="false-positive">The risk has been confirmed to be a false positive.</enum>
             <enum value="accepted">The risk has been accepted. No further action will be taken.</enum>
             <enum value="risk-adjusted">The risk has been adjusted.</enum>
             <enum value="priority">A numeric value indicating the sequence in which risks should be addressed. (Lower numbers are higher priority)</enum>
          </allowed-values>
-         <matches id="oscal-risk-priority-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='priority']/@value" datatype="integer" />
+         <matches id="oscal-risk-priority-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='priority']/@value" datatype="integer" />
       </constraint>
    </define-assembly>
 
@@ -1405,10 +1405,10 @@
                <field ref="remarks" in-xml="WITH_WRAPPER"/>
             </model>
             <constraint>
-               <allowed-values id="oscal-facet-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+               <allowed-values id="oscal-facet-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                   <enum value="state">Indicates if the facet is 'initial' as first identified, or 'adjusted' indicating that the value has be changed after some adjustments have been made (e.g., to identify residual risk).</enum>
                </allowed-values>
-               <allowed-values id="oscal-facet-prop-state-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='state']/@value"><!-- For values related to initial and residual (mitigated) risk -->
+               <allowed-values id="oscal-facet-prop-state-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='state']/@value"><!-- For values related to initial and residual (mitigated) risk -->
                   <enum value="initial">As first identified.</enum>
                   <enum value="adjusted">Indicates that residual risk remains after some adjustments have been made.</enum>
                </allowed-values>
@@ -1854,10 +1854,10 @@
          <field ref="remarks" in-xml="WITH_WRAPPER" min-occurs="0" max-occurs="1"/>
       </model>
       <constraint>
-         <allowed-values id="oscal-response-prop-name" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+         <allowed-values id="oscal-response-prop-name" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             <enum value="type">Risk Response Type</enum>
          </allowed-values>
-         <allowed-values id="oscal-response-prop-type-value" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='type']/@value">
+         <allowed-values id="oscal-response-prop-type-value" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='type']/@value">
             <enum value="avoid">The risk will be eliminated.</enum>
             <enum value="mitigate">The risk will be reduced.</enum>
             <enum value="transfer">The risk will be transferred to another organization or entity.</enum>
@@ -1937,11 +1937,11 @@
          <!-- <any/> -->
       </model>
       <constraint>
-         <allowed-values id="oscal-assesment-part-objective-name" target=".[@name='objective']/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+         <allowed-values id="oscal-assesment-part-objective-name" target=".[@name='objective']/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             <enum value="method">The assessment method to use. This typically appears on parts with the name "objective".</enum>
          </allowed-values>
-         <has-cardinality id="oscal-assesment-part-objective-cardinality" target=".[@name='objective']/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='method']" min-occurs="1"/>
-         <allowed-values id="oscal-assesment-part-objective-method-value" target=".[@name='objective']/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='method']/@value">
+         <has-cardinality id="oscal-assesment-part-objective-cardinality" target=".[@name='objective']/prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='method']" min-occurs="1"/>
+         <allowed-values id="oscal-assesment-part-objective-method-value" target=".[@name='objective']/prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='method']/@value">
             <enum value="INTERVIEW">The process of holding discussions with individuals or groups of individuals within an organization to once again, facilitate assessor understanding, achieve clarification, or obtain evidence.</enum>
             <enum value="EXAMINE">The process of reviewing, inspecting, observing, studying, or analyzing one or more assessment objects (i.e., specifications, mechanisms, or activities).</enum>
             <enum value="TEST">The process of exercising one or more assessment objects (i.e., activities or mechanisms) under specified conditions to compare actual with expected behavior.</enum>
diff --git a/src/metaschema/oscal_assessment-plan_metaschema.xml b/src/metaschema/oscal_assessment-plan_metaschema.xml
index 55a452b178..dd54bc8c95 100644
--- a/src/metaschema/oscal_assessment-plan_metaschema.xml
+++ b/src/metaschema/oscal_assessment-plan_metaschema.xml
@@ -91,7 +91,7 @@
                     </assembly>
                 </model>
                 <constraint>
-                    <allowed-values id="oscal-terms-and-conditions-part-name" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                    <allowed-values id="oscal-terms-and-conditions-part-name" target="part[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="rules-of-engagement">Defines the circumstances, conditions, degree, and manner in which the use of cyber-attack techniques or actions may be applied to the assessment.</enum>
                         <enum value="disclosures">Any information the assessor should make known to the system owner or authorizing official. Has child 'item' parts for each individual disclosure.</enum>
                         <enum value="assessment-inclusions">Defines any assessment activities which the system owner or authorizing official wishes to ensure are performed as part of the assessment.</enum>
diff --git a/src/metaschema/oscal_catalog_metaschema.xml b/src/metaschema/oscal_catalog_metaschema.xml
index 8b476aa612..6dd4d27c40 100644
--- a/src/metaschema/oscal_catalog_metaschema.xml
+++ b/src/metaschema/oscal_catalog_metaschema.xml
@@ -49,7 +49,7 @@
                   </assembly>
             </model>
             <constraint>
-                  <allowed-values id="oscal-catalog-metadata-prop-name" target="metadata/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-catalog-metadata-prop-name" target="metadata/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="resolution-tool">The tool used to produce a resolved profile.</enum>
                         <enum value="source-profile-uuid">The document-level <code>uuid</code> of the source profile from which the catalog was produced by <a href="https://pages.nist.gov/OSCAL/concepts/processing/profile-resolution/">profile resolution</a>.</enum>
                   </allowed-values>
@@ -141,10 +141,10 @@
                   <!--<any/>-->
             </model>
             <constraint>
-                  <allowed-values id="oscal-group-prop-name" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-group-prop-name" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             &allowed-values-control-group-property-name;
                   </allowed-values>
-                  <allowed-values id="oscal-group-part-name" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-group-part-name" target="part[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="overview">An introduction to a control or a group of controls.</enum>
                         <enum value="instruction">Information providing directions for a control or a group of controls.</enum>
                   </allowed-values>
@@ -222,14 +222,14 @@
                   <expect id="oscal-catalog-control-require-statement-when-not-withdrawn" target="."
                         test="prop[@name='status']/@value=('withdrawn','Withdrawn') or part[@name='statement']"/>
                   <allowed-values id="oscal-control-prop-name"
-                        target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         &allowed-values-control-group-property-name;
                         <enum value="status">The status of a <code>control</code>. For example, a
                               value of 'withdrawn' can indicate that the <code>control</code> has
                               been withdrawn and should no longer be used.</enum>
                   </allowed-values>
                   <allowed-values id="oscal-control-prop-status-value"
-                        target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='status']/@value">
+                        target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='status']/@value">
                         <enum value="withdrawn">The control is no longer used.</enum>
                         <enum value="Withdrawn" deprecated="1.0.0">**(deprecated)*** Use 'withdrawn'
                               instead.</enum>
@@ -252,7 +252,7 @@
                         <key-field target="@href" pattern="#(.*)"/>
                   </index-has-key>
                   <allowed-values id="oscal-control-part-name"
-                        target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        target="part[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="overview">An introduction to a control or a group of
                               controls.</enum>
                         <enum value="statement">A set of implementation requirements or recommendations.</enum>
@@ -265,14 +265,14 @@
                               over a set of assessment objects.</enum>
                   </allowed-values>
                   <allowed-values id="oscal-control-statement-part-subpart-name"
-                        target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='statement']//part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='statement']//part[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="item">An individual item within a control statement.</enum>
                         <remarks>
                               <p>Nested statement parts are "item" parts.</p>
                         </remarks>
                   </allowed-values>
                   <allowed-values id="oscal-control-statement-part-name"
-                        target=".//part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        target=".//part[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="objective" deprecated="1.0.1">**(deprecated)** Use
                               'assessment-objective' instead.</enum>
                         <enum value="assessment-objective">The part describes a set of assessment
@@ -282,7 +282,7 @@
                         </remarks>
                   </allowed-values>
                   <allowed-values id="oscal-control-objective-part-subpart-name"
-                        target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('assessment','assessment-method')]/part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('assessment','assessment-method')]/part[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="objects" deprecated="1.0.1">**(deprecated)** Use
                               'assessment-objects' instead.</enum>
                         <enum value="assessment-objects">Provides a listing of assessment
@@ -292,17 +292,17 @@
                         </remarks>
                   </allowed-values>
                   <allowed-values id="oscal-control-statement-part-prop-name"
-                        target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('assessment','assessment-method')]/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('assessment','assessment-method')]/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="method" deprecated="1.0.1">**(deprecated)** Use 'method' in the 'http://csrc.nist.gov/ns/rmf' namespace. The assessment method to use. This typically appears on parts with the name "assessment-method".</enum>
                   </allowed-values>
                   <allowed-values id="oscal-control-statement-part-rmf-prop-name"
-                        target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('assessment','assessment-method')]/prop[has-oscal-namespace('http://csrc.nist.gov/ns/rmf')]/@name">
+                        target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('assessment','assessment-method')]/prop[has-oscal-namespace('http://csrc.nist.gov/ns/rmf')]/@name">
                         <enum value="method">The assessment method to use. This typically appears on
                               parts with the name "assessment-method".</enum>
                   </allowed-values>
-                  <expect level="WARNING" id="oscal-method-part-has-method-prop" target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('assessment','assessment-method')]" test="prop[has-oscal-namespace(('http://csrc.nist.gov/ns/oscal','http://csrc.nist.gov/ns/rmf')) and @name='method']"/>
+                  <expect level="WARNING" id="oscal-method-part-has-method-prop" target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('assessment','assessment-method')]" test="prop[has-oscal-namespace(('http://csrc.nist.gov/ns/oscal','http://csrc.nist.gov/ns/rmf')) and @name='method']"/>
                   <allowed-values id="oscal-control-objective-part-method-prop-value"
-                        target="part[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('assessment','assessment-method')]/prop[has-oscal-namespace(('http://csrc.nist.gov/ns/oscal','http://csrc.nist.gov/ns/rmf')) and @name='method']/@value">
+                        target="part[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('assessment','assessment-method')]/prop[has-oscal-namespace(('http://csrc.nist.gov/ns/oscal','http://csrc.nist.gov/ns/rmf')) and @name='method']/@value">
                         <enum value="INTERVIEW">The process of holding discussions with individuals or groups of individuals within an organization to once again, facilitate assessor understanding, achieve clarification, or obtain evidence.</enum>
                         <enum value="EXAMINE">The process of reviewing, inspecting, observing, studying, or analyzing one or more assessment objects (i.e., specifications, mechanisms, or activities).</enum>
                         <enum value="TEST">The process of exercising one or more assessment objects (i.e., activities or mechanisms) under specified conditions to compare actual with expected behavior.</enum>
diff --git a/src/metaschema/oscal_component_metaschema.xml b/src/metaschema/oscal_component_metaschema.xml
index f70fcdb0cb..7a37af33cd 100644
--- a/src/metaschema/oscal_component_metaschema.xml
+++ b/src/metaschema/oscal_component_metaschema.xml
@@ -148,7 +148,7 @@
       <field ref="remarks" in-xml="WITH_WRAPPER"/>
     </model>
     <constraint>
-      <allowed-values id="oscal-component-prop-name" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+      <allowed-values id="oscal-component-prop-name" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
         <!-- ========================================================================================================== -->
         <!-- = Changes to the following values need to be synced with component in the SSP and component metaschemas. = -->
         <!-- CHANGED (BJR): Done -->
@@ -177,7 +177,7 @@
             &allowed-values-responsible-roles-component-production;
       </allowed-values>
 
-      <allowed-values id="oscal-component-asset-type-value" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='asset-type']/@value" allow-other="yes">
+      <allowed-values id="oscal-component-asset-type-value" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='asset-type']/@value" allow-other="yes">
             &allowed-values-property-name-asset-type-values;
       </allowed-values>
 
@@ -185,22 +185,22 @@
       <!-- = TODO: The following was copied from implementation-common as-is and should probably be setup with  = -->
       <!-- =       shared constraints; however, the values are highly static (yes/no, internal/external). -->
       <!-- =       Can be changed later with no breaking impact. -->
-      <allowed-values id="oscal-component-allows-authenticated-scan-value" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='allows-authenticated-scan']/@value">
+      <allowed-values id="oscal-component-allows-authenticated-scan-value" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='allows-authenticated-scan']/@value">
         <enum value="yes">The component allows an authenticated scan.</enum>
         <enum value="no">The component does not allow an authenticated scan.</enum>
       </allowed-values>
 
-      <allowed-values id="oscal-component-virtual-value" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='virtual']/@value">
+      <allowed-values id="oscal-component-virtual-value" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='virtual']/@value">
         <enum value="yes">The component is virtualized.</enum>
         <enum value="no">The component is not virtualized.</enum>
       </allowed-values>
 
-      <allowed-values id="oscal-component-public-value" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='public']/@value">
+      <allowed-values id="oscal-component-public-value" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='public']/@value">
         <enum value="yes">The component is publicly accessible.</enum>
         <enum value="no">The component is not publicly accessible.</enum>
       </allowed-values>
 
-      <allowed-values id="oscal-component-implementation-point-value" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='implementation-point']/@value">
+      <allowed-values id="oscal-component-implementation-point-value" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='implementation-point']/@value">
         <enum value="internal">The component is implemented within the system boundary.</enum>
         <enum value="external">The component is implemented outside the system boundary.</enum>
       </allowed-values>
@@ -210,8 +210,8 @@
         <key-field target="@value"/>
       </index-has-key>
 
-      <matches id="oscal-component-inherited-uuid-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='inherited-uuid']/@value" datatype="uuid" />
-      <matches id="oscal-component-release-date-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='release-date']/@value" datatype="date"/>
+      <matches id="oscal-component-inherited-uuid-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='inherited-uuid']/@value" datatype="uuid" />
+      <matches id="oscal-component-release-date-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='release-date']/@value" datatype="date"/>
 
       <!-- ========================================================================================================== -->
       <!-- = Changes to the following values need to be synced with component in the SSP and component metaschemas. = -->
@@ -221,7 +221,7 @@
       <!-- ========================================================================================================== -->
       <!-- = SOFTWARE: type='software' constraints                        = -->
       <!-- ========================================================================================================== -->
-      <allowed-values id="oscal-software-component-prop-name" target="(.)[@type='software']/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+      <allowed-values id="oscal-software-component-prop-name" target="(.)[@type='software']/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             &allowed-values-component_component_software;
       </allowed-values>
 
diff --git a/src/metaschema/oscal_control-common_metaschema.xml b/src/metaschema/oscal_control-common_metaschema.xml
index 4bae078550..8f4ea26c8c 100644
--- a/src/metaschema/oscal_control-common_metaschema.xml
+++ b/src/metaschema/oscal_control-common_metaschema.xml
@@ -76,7 +76,7 @@
                         <!-- <any/> -->
                 </model>
                 <constraint>
-                        <allowed-values id="oscal-part-prop-name" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        <allowed-values id="oscal-part-prop-name" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             &allowed-values-control-group-property-name;
                         </allowed-values>
                 </constraint>
@@ -179,7 +179,7 @@
                         <field ref="remarks" in-xml="WITH_WRAPPER"/>
                 </model>
                 <constraint>
-                        <allowed-values id="oscal-parameter-prop-name" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                        <allowed-values id="oscal-parameter-prop-name" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                                 &allowed-values-control-group-property-name;
                                 <enum value="alt-label">An alternate to the value provided by the parameter's label. This will typically be qualified by a class.</enum>
                         </allowed-values>
diff --git a/src/metaschema/oscal_implementation-common_metaschema.xml b/src/metaschema/oscal_implementation-common_metaschema.xml
index b4def97907..b46641de18 100644
--- a/src/metaschema/oscal_implementation-common_metaschema.xml
+++ b/src/metaschema/oscal_implementation-common_metaschema.xml
@@ -88,7 +88,7 @@
                   <field ref="remarks" in-xml="WITH_WRAPPER"/>
             </model>
             <constraint>
-                  <allowed-values id="oscal-component-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-component-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <!-- names related to inherited component -->
                         <enum value="implementation-point">Relative placement of component ('internal' or 'external') to the system.</enum>
                         <enum value="leveraged-authorization-uuid">UUID of the related leveraged-authorization assembly in this SSP.</enum>
@@ -121,26 +121,26 @@
             &allowed-values-responsible-roles-component-production;
                   </allowed-values>
 
-                  <allowed-values id="oscal-component-prop-asset-type-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='asset-type']/@value" allow-other="yes">
+                  <allowed-values id="oscal-component-prop-asset-type-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='asset-type']/@value" allow-other="yes">
             &allowed-values-property-name-asset-type-values;
                   </allowed-values>
 
-                  <allowed-values id="oscal-component-prop-allows-authenticated-scan-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='allows-authenticated-scan']/@value">
+                  <allowed-values id="oscal-component-prop-allows-authenticated-scan-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='allows-authenticated-scan']/@value">
                         <enum value="yes">The component allows an authenticated scan.</enum>
                         <enum value="no">The component does not allow an authenticated scan.</enum>
                   </allowed-values>
 
-                  <allowed-values id="oscal-component-prop-is-public-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='public']/@value">
+                  <allowed-values id="oscal-component-prop-is-public-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='public']/@value">
                         <enum value="yes">The component is publicly accessible.</enum>
                         <enum value="no">The component is not publicly accessible.</enum>
                   </allowed-values>
 
-                  <allowed-values id="oscal-component-prop-is-virtual-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='virtual']/@value">
+                  <allowed-values id="oscal-component-prop-is-virtual-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='virtual']/@value">
                         <enum value="yes">The component is virtualized.</enum>
                         <enum value="no">The component is not virtualized.</enum>
                   </allowed-values>
 
-                  <allowed-values id="oscal-component-prop-implementation-point-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='implementation-point']/@value">
+                  <allowed-values id="oscal-component-prop-implementation-point-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='implementation-point']/@value">
                         <enum value="internal">The component is implemented within the system boundary.</enum>
                         <enum value="external">The component is implemented outside the system boundary.</enum>
                   </allowed-values>
@@ -149,14 +149,14 @@
                         <key-field target="@value"/>
                   </index-has-key>
 
-                  <matches id="oscal-component-inherited-uuid-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='inherited-uuid']/@value" datatype="uuid" />
-                  <matches id="oscal-component-release-date-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='release-date']/@value" datatype="date"/>
+                  <matches id="oscal-component-inherited-uuid-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='inherited-uuid']/@value" datatype="uuid" />
+                  <matches id="oscal-component-release-date-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='release-date']/@value" datatype="date"/>
 
                   <!-- ========================================================================================================== -->
                   <!-- = Changes to the following values need to be synced with component in the SSP and component metaschemas. = -->
                   <!-- ========================================================================================================== -->
 
-                  <allowed-values id="oscal-component-hardware-service-software-prop-name-values" target="(.)[@type=('software', 'hardware', 'service')]/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-component-hardware-service-software-prop-name-values" target="(.)[@type=('software', 'hardware', 'service')]/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="vendor-name">The name of the company or organization </enum>
                   </allowed-values>
 
@@ -173,7 +173,7 @@
                   <!-- ========================================================================================================== -->
                   <!-- = SOFTWARE: type='software' constraints                        = -->
                   <!-- ========================================================================================================== -->
-                  <allowed-values id="oscal-component-software-prop-name-values" target="(.)[@type='software']/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-component-software-prop-name-values" target="(.)[@type='software']/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             &allowed-values-component_component_software;
                   </allowed-values>
 
@@ -187,16 +187,16 @@
                   <!-- ========================================================================================================== -->
                   <!-- = INTERCONNECTION: type='interconnection' constraints                        = -->
                   <!-- ========================================================================================================== -->
-                  <allowed-values id="oscal-component-interconnection-prop-name-values" target="(.)[@type='interconnection']/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-component-interconnection-prop-name-values" target="(.)[@type='interconnection']/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="isa-title">Title of the Interconnection Security Agreement (ISA).</enum>
                         <enum value="isa-date">Date of the Interconnection Security Agreement (ISA).</enum>
                         <enum value="isa-remote-system-name">The name of the remote interconnected system.</enum>
             &allowed-values-property-name-networked-components;
                   </allowed-values>
-                  <allowed-values id="oscal-component-service-software-prop-name-values" target="[@type=('service', 'software')]/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-component-service-software-prop-name-values" target="[@type=('service', 'software')]/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
             &allowed-values-property-name-networked-components;                        
                   </allowed-values> 
-                  <allowed-values  id="oscal-component-prop-ipaddress-class-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name=('ipv4-address','ipv6-address')]/@class">
+                  <allowed-values  id="oscal-component-prop-ipaddress-class-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name=('ipv4-address','ipv6-address')]/@class">
                         <enum value="local">The identified IP address is for this system.</enum>
                         <enum value="remote">The identified IP address is for the remote system to which this system is connected.</enum>
                   </allowed-values>
@@ -210,11 +210,11 @@
                         <enum value="isa-authorizing-official-local">Interconnection Security Agreement (ISA) authorizing official for this system.</enum>
                         <enum value="isa-authorizing-official-remote">Interconnection Security Agreement (ISA) authorizing official for the remote interconnected system.</enum>
                   </allowed-values>
-                  <matches id="oscal-component-prop-isa-date-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='isa-date']/@value" datatype="date-time"/>
-                  <matches id="oscal-component-prop-ipv4address-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='ipv4-address']/@value" datatype="ip-v4-address" />
-                  <matches id="oscal-component-prop-ipv6address-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='ipv6-address']/@value" datatype="ip-v6-address" />
-                  <matches id="oscal-component-prop-uri-value-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='uri']/@value" datatype="uri" />
-                  <allowed-values id="oscal-component-prop-direction-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='direction']/@value">
+                  <matches id="oscal-component-prop-isa-date-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='isa-date']/@value" datatype="date-time"/>
+                  <matches id="oscal-component-prop-ipv4address-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='ipv4-address']/@value" datatype="ip-v4-address" />
+                  <matches id="oscal-component-prop-ipv6address-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='ipv6-address']/@value" datatype="ip-v6-address" />
+                  <matches id="oscal-component-prop-uri-value-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='uri']/@value" datatype="uri" />
+                  <allowed-values id="oscal-component-prop-direction-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='direction']/@value">
                         <enum value="incoming">Data from the remote system flows into this system.</enum>
                         <enum value="outgoing">Data from this system flows to the remote system.</enum>
                   </allowed-values>
@@ -404,16 +404,16 @@
                   <field ref="remarks" in-xml="WITH_WRAPPER"/>
             </model>
             <constraint>
-                  <allowed-values id="oscal-user-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-user-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="type">The type of user, such as internal, external, or general-public.</enum>
                         <enum value="privilege-level">The user's privilege level within the system, such as privileged, non-privileged, no-logical-access.</enum>
                   </allowed-values>
-                  <allowed-values id="oscal-user-prop-type-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='type']/@value">
+                  <allowed-values id="oscal-user-prop-type-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='type']/@value">
                         <enum value="internal">A user account for a person or entity that is part of the organization who owns or operates the system.</enum>
                         <enum value="external">A user account for a person or entity that is not part of the organization who owns or operates the system.</enum>
                         <enum value="general-public">A user of the system considered to be outside </enum>
                   </allowed-values>
-                  <allowed-values id="oscal-user-prop-privilege-level-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='privilege-level']/@value">
+                  <allowed-values id="oscal-user-prop-privilege-level-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='privilege-level']/@value">
                         <enum value="privileged">This role has elevated access to the system, such as a group or system administrator.</enum>
                         <enum value="non-privileged">This role has typical user-level access to the system without elevated access.</enum>
                         <enum value="no-logical-access">This role has no access to the system, such as a manager who approves access as part of a process.</enum>
@@ -533,7 +533,7 @@
                               <!-- TODO: constrain link href values based on rel ((BJR): Was unsure of how to do this.) -->
 
                               <!-- TODO: constrain property values based on name (CHANGED (BJR): Done.) -->
-                              <allowed-values id="oscal-implemented-component-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                              <allowed-values id="oscal-implemented-component-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                   &allowed-values-component_component_property-name;
                   &allowed-values-component_inventory-item_property-name;
 
@@ -557,7 +557,7 @@
                   <field ref="remarks" in-xml="WITH_WRAPPER"/>
             </model>
             <constraint>
-                  <allowed-values id="oscal-inventory-item-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-inventory-item-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="ipv4-address">The Internet Protocol v4 Address of the asset.</enum>
                         <enum value="ipv6-address">The Internet Protocol v6 Address of the asset.</enum>
                         <enum value="fqdn">The full-qualified domain name (FQDN) of the asset.</enum>
@@ -589,16 +589,16 @@
                         &allowed-values-component_inventory-item_property-name;
 
                   </allowed-values>
-                  <allowed-values id="oscal-inventory-item-prop-asset-type-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='asset-type']/@value" allow-other="yes">
+                  <allowed-values id="oscal-inventory-item-prop-asset-type-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='asset-type']/@value" allow-other="yes">
                         &allowed-values-property-name-asset-type-values;
                   </allowed-values>
 
-                  <allowed-values id="oscal-inventory-item-hardware-service-software-prop-name-values" target="(.)[@type=('software', 'hardware', 'service')]/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                  <allowed-values id="oscal-inventory-item-hardware-service-software-prop-name-values" target="(.)[@type=('software', 'hardware', 'service')]/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="vendor-name">The name of the company or organization </enum>
                   </allowed-values>
 
 
-                  <allowed-values id="oscal-inventory-item-prop-is-scanned-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='is-scanned']/@value">
+                  <allowed-values id="oscal-inventory-item-prop-is-scanned-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='is-scanned']/@value">
                         <enum value="yes">The asset is included in periodic vulnerability scanning.</enum>
                         <enum value="no">The asset is not included in periodic vulnerability scanning.</enum>
                   </allowed-values>
diff --git a/src/metaschema/oscal_metadata_metaschema.xml b/src/metaschema/oscal_metadata_metaschema.xml
index be28d1206b..ef9c3ddc90 100644
--- a/src/metaschema/oscal_metadata_metaschema.xml
+++ b/src/metaschema/oscal_metadata_metaschema.xml
@@ -203,13 +203,13 @@
                     <field ref="remarks" in-xml="WITH_WRAPPER"/>
                 </model>
                 <constraint>
-                    <allowed-values id="oscal-metadata-location-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                    <allowed-values id="oscal-metadata-location-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="type">Characterizes the kind of location.</enum>
                     </allowed-values>
-                    <allowed-values id="oscal-metadata-location-prop-type-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='type']/@value">
+                    <allowed-values id="oscal-metadata-location-prop-type-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='type']/@value">
                         <enum value="data-center">A location that contains computing assets. A <code>class</code> can be used to indicate the sub-type of data-center as <em>primary</em> or <em>alternate</em>.</enum>
                     </allowed-values>
-                    <allowed-values id="oscal-metadata-location-prop-type-data-center-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='type' and @value='data-center']/@class">
+                    <allowed-values id="oscal-metadata-location-prop-type-data-center-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='type' and @value='data-center']/@class">
                         <enum value="primary">The location is a data-center used for normal operations.</enum>
                         <enum value="alternate">The location is a data-center used for fail-over or backup operations.</enum>
                     </allowed-values>
@@ -326,7 +326,7 @@
                     <field ref="remarks" in-xml="WITH_WRAPPER"/>
                 </model>
                 <constraint>
-                    <allowed-values id="oscal-metadata-party-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                    <allowed-values id="oscal-metadata-party-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="mail-stop">A mail stop associated with the party.</enum>
                         <enum value="office">The name or number of the party's office.</enum>
                         <enum value="job-title">The formal job title of a person.</enum>
@@ -404,7 +404,7 @@
                 <enum value="content-approver">Indicates the person or organization responsible for all content represented in the "document".</enum>
                 <enum value="contact">Indicates the person or organization to contact for questions or support related to this content.</enum>
             </allowed-values>
-            <allowed-values id="oscal-metadata-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+            <allowed-values id="oscal-metadata-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                 <enum value="keywords">The value identifies a comma-seperated listing of keywords associated with this content. These keywords may be used as search terms for indexing and other applications.</enum>
             </allowed-values>
             <allowed-values id="oscal-metadata-link-rel-values" target="link/@rel" allow-other="yes">
@@ -568,13 +568,13 @@
                     <!-- <any/> -->
                 </model>
                 <constraint>
-                    <allowed-values id="oscal-back-matter-resource-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                    <allowed-values id="oscal-back-matter-resource-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                         <enum value="type">Identifies the type of resource represented. The most specific appropriate type value SHOULD be used.</enum>
                         <enum value="version">For resources representing a published document, this represents the version number of that document.</enum>
                         <enum value="published">For resources representing a published document, this represents the publication date of that document.</enum>
                     </allowed-values>
-                    <matches id="oscal-back-matter-resource-prop-published-datatype" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='published']/@value" datatype="date-time-with-timezone"/>
-                    <allowed-values id="oscal-back-matter-resource-prop-type-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='type']/@value">
+                    <matches id="oscal-back-matter-resource-prop-published-datatype" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='published']/@value" datatype="date-time-with-timezone"/>
+                    <allowed-values id="oscal-back-matter-resource-prop-type-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='type']/@value">
                         <!-- More general. Applies across all models. -->
                         <enum value="logo">Indicates the resource is an organization's logo.</enum>
                         <enum value="image">Indicates the resource represents an image.</enum>
@@ -702,7 +702,7 @@
             <field ref="remarks" in-xml="WITH_WRAPPER"/>
         </model>
         <constraint>
-            <allowed-values id="oscal-metadata-prop-name-values" target=".[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+            <allowed-values id="oscal-metadata-prop-name-values" target=".[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                 <enum value="marking">A label or descriptor that is tied to a sensitivity or classification marking system. An optional class can be used to define the specific marking system used for the associated value.</enum>
             </allowed-values>
         </constraint>
@@ -874,7 +874,7 @@
             <allowed-values id="oscal-metadata-action-system-values" target="./system/@value" allow-other="yes">
                 <enum value="http://csrc.nist.gov/ns/oscal">This value identifies action types defined in the NIST OSCAL namespace.</enum>
              </allowed-values>
-             <allowed-values id="oscal-metadata-action-type-values" target="./type[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@value">
+             <allowed-values id="oscal-metadata-action-type-values" target="./type[@ns = 'http://csrc.nist.gov/ns/oscal']/@value">
                 <enum value="approval">An approval of a document instance's content.</enum>
                 <enum value="request-changes">A request from the responisble party or parties to change the content.</enum>
             </allowed-values>
diff --git a/src/metaschema/oscal_profile_metaschema.xml b/src/metaschema/oscal_profile_metaschema.xml
index 0caddb6a18..310034dc3a 100644
--- a/src/metaschema/oscal_profile_metaschema.xml
+++ b/src/metaschema/oscal_profile_metaschema.xml
@@ -377,7 +377,7 @@
                                           </assembly>
                                     </model>
                                     <constraint>
-                                          <allowed-values id="oscal-profile-modify-alter-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+                                          <allowed-values id="oscal-profile-modify-alter-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
                                                 &allowed-values-control-group-property-name;
                                           </allowed-values>
                                     </constraint>
diff --git a/src/metaschema/oscal_ssp_metaschema.xml b/src/metaschema/oscal_ssp_metaschema.xml
index d70d0796b3..8c6c62ce23 100644
--- a/src/metaschema/oscal_ssp_metaschema.xml
+++ b/src/metaschema/oscal_ssp_metaschema.xml
@@ -129,7 +129,7 @@
       <field ref="remarks" in-xml="WITH_WRAPPER"/>
     </model>
     <constraint>
-      <allowed-values id="oscal-system-characteristics-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+      <allowed-values id="oscal-system-characteristics-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
         <enum value="identity-assurance-level">A value of 1, 2, or 3 as defined by <a href="https://doi.org/10.6028/NIST.SP.800-63-3">SP 800-63-3</a>.
         </enum>
         <enum value="authenticator-assurance-level">A value of 1, 2, or 3 as defined by <a href="https://doi.org/10.6028/NIST.SP.800-63-3">SP 800-63-3</a>.
@@ -145,11 +145,11 @@
         <enum value="3">As defined by <a href="https://doi.org/10.6028/NIST.SP.800-63-3">SP 800-63-3</a>.
         </enum>
       </allowed-values>
-      <allowed-values id="oscal-system-characteristics-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+      <allowed-values id="oscal-system-characteristics-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
         <enum value="cloud-deployment-model">The associated value is one of: public-cloud, private-cloud, community-cloud, government-only-cloud, hybrid-cloud, or other.</enum>
         <enum value="cloud-service-model">The associated value is one of: saas, paas, iaas, or other.</enum>
       </allowed-values>
-      <allowed-values id="oscal-system-characteristics-prop-cloud-deployment-model-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='cloud-deployment-model']/@value">
+      <allowed-values id="oscal-system-characteristics-prop-cloud-deployment-model-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='cloud-deployment-model']/@value">
         <enum value="public-cloud">The public cloud deployment model as defined by <a href="https://doi.org/10.6028/NIST.SP.800-145">The NIST Definition of Cloud Computing</a>.
         </enum>
         <enum value="private-cloud">The private cloud deployment model as defined by <a href="https://doi.org/10.6028/NIST.SP.800-145">The NIST Definition of Cloud Computing</a>.
@@ -165,7 +165,7 @@
           <p>The hybrid cloud deployment model, as defined by <a href="https://doi.org/10.6028/NIST.SP.800-145">The NIST Definition of Cloud Computing</a>, can be supported by selecting two or more of the existing deployment models.</p>
         </remarks>
       </allowed-values>
-      <allowed-values id="oscal-system-characteristics-prop-cloud-service-model-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='cloud-service-model']/@value">
+      <allowed-values id="oscal-system-characteristics-prop-cloud-service-model-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='cloud-service-model']/@value">
         <enum value="saas">Software as a service (SaaS) cloud service model as defined by <a href="https://doi.org/10.6028/NIST.SP.800-145">The NIST Definition of Cloud Computing</a>.
         </enum>
         <enum value="paas">Platform as a service (PaaS) cloud service model as defined by <a href="https://doi.org/10.6028/NIST.SP.800-145">The NIST Definition of Cloud Computing</a>.
@@ -271,10 +271,10 @@
       </define-assembly>
     </model>
     <constraint>
-      <allowed-values id="oscal-system-information-prop-name-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+      <allowed-values id="oscal-system-information-prop-name-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
         <enum value="privacy-designation">Is this a privacy sensitive system? yes or no</enum>
       </allowed-values>
-      <allowed-values id="oscal-system-information-prop-privacy-designation-values" target="prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='privacy-designation']/@value">
+      <allowed-values id="oscal-system-information-prop-privacy-designation-values" target="prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='privacy-designation']/@value">
         <enum value="yes">The system is privacy sensitive.</enum>
         <enum value="no">The system is not privacy sensitive.</enum>
       </allowed-values>
@@ -634,7 +634,7 @@
       </index-has-key>
 
       <!-- TODO: check that prop names are defined -->
-      <allowed-values id="oscal-component-inventory-item-allows-authenticated-scan-values" target="(component | inventory-item)/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='allows-authenticated-scan']/@value">
+      <allowed-values id="oscal-component-inventory-item-allows-authenticated-scan-values" target="(component | inventory-item)/prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='allows-authenticated-scan']/@value">
         <enum value="yes">The component allows an authenticated scan.</enum>
         <enum value="no">The component does not allow an authenticated scan.</enum>
       </allowed-values>
@@ -713,10 +713,10 @@
       <field ref="remarks" in-xml="WITH_WRAPPER"/>
     </model>
     <constraint>
-      <allowed-values id="oscal-implemented-requirement-statement-by-component-prop-name-values" target="(.|statement|.//by-component)/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal')]/@name">
+      <allowed-values id="oscal-implemented-requirement-statement-by-component-prop-name-values" target="(.|statement|.//by-component)/prop[@ns = 'http://csrc.nist.gov/ns/oscal']/@name">
         <enum value="control-origination">Identifies the source of the implemented control.  Any <code>control-origination</code> prop defined in a child context will override the parent value.</enum>
       </allowed-values>
-      <allowed-values id="oscal-implemented-requirement-statement-by-component-prop-control-origination-values" target="(.|statement|.//by-component)/prop[has-oscal-namespace('http://csrc.nist.gov/ns/oscal') and @name='control-origination']/@value">
+      <allowed-values id="oscal-implemented-requirement-statement-by-component-prop-control-origination-values" target="(.|statement|.//by-component)/prop[@ns = 'http://csrc.nist.gov/ns/oscal' and @name='control-origination']/@value">
         <enum value="organization">The control is implemented by the organization owning the system, but is not specific to the system itself.</enum>
         <enum value="system-specific">The control is implemented specifically to this system.</enum>
         <enum value="customer-configured">The control is provided by the system, but must be configured by the customer.</enum>