diff --git a/LICENSE-binary.txt b/LICENSE-binary.txt
index 759c30c8c..13191cf7b 100755
--- a/LICENSE-binary.txt
+++ b/LICENSE-binary.txt
@@ -234,4 +234,4 @@ org.slf4j:slf4j-api:1.7.25
 Mozilla Public License 2.0
 --------------------------
 
-net.sf.saxon:Saxon-HE:11.5
+net.sf.saxon:Saxon-HE:12.3
diff --git a/build.gradle b/build.gradle
index e19ab851f..5be777440 100644
--- a/build.gradle
+++ b/build.gradle
@@ -69,7 +69,7 @@ ext {
     antVersion = '1.10.14'
     javaparserVersion = '3.25.5'
     log4jVersion = '2.20.0'
-    saxonVersion = '11.5'
+    saxonVersion = '12.3'
     androidSdkMinimum = '26'
 }
 
diff --git a/build.xml b/build.xml
index f80a00931..9245bf17c 100644
--- a/build.xml
+++ b/build.xml
@@ -121,7 +121,7 @@
     <!-- dependencies -->
     <dependency prefix="xml-apis" artifact="xml-apis:xml-apis:1.4.01" usage="java8"/>
     <dependency prefix="log4j-api" artifact="org.apache.logging.log4j:log4j-api:2.20.0" usage="main"/>
-    <dependency prefix="saxon" artifact="net.sf.saxon:Saxon-HE:11.5" usage="main"/>
+    <dependency prefix="saxon" artifact="net.sf.saxon:Saxon-HE:12.3" usage="main"/>
     <dependency prefix="ant" artifact="org.apache.ant:ant:1.10.14" usage="main"/>
     <dependency prefix="javaparser-core" artifact="com.github.javaparser:javaparser-core:3.25.5" usage="main"/>
     <dependency prefix="javaparser-symbol-solver-core" artifact="com.github.javaparser:javaparser-symbol-solver-core:3.25.5" usage="main"/>
diff --git a/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXPath.java b/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXPath.java
index a6aaa4ae4..c0362efee 100644
--- a/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXPath.java
+++ b/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXPath.java
@@ -18,6 +18,7 @@
 import net.sf.saxon.Configuration;
 import net.sf.saxon.dom.DOMNodeWrapper;
 import net.sf.saxon.om.Item;
+import net.sf.saxon.om.NamespaceUri;
 import net.sf.saxon.om.NodeInfo;
 import net.sf.saxon.om.SequenceTool;
 import net.sf.saxon.sxpath.*;
@@ -94,16 +95,18 @@ public List selectNodes(Object node) {
             // also see https://saxonica.plan.io/issues/2130
             // (XPath referencing attribute with namespace fails when using DOM)
             if (defaultNS != null) {
-                sc.setDefaultElementNamespace(defaultNS);
+                sc.setDefaultElementNamespace(NamespaceUri.of(defaultNS));
             }
 
-            namespaceMap.forEach(sc::declareNamespace);
+            for (Map.Entry<String, String> entry : namespaceMap.entrySet()) {
+                sc.declareNamespace(entry.getKey(), NamespaceUri.of(entry.getValue()));
+            }
 
             NodeInfo contextItem = config.unravel(new DOMSource(contextNode));
 
             XPathEvaluator xpe = new XPathEvaluator(config);
             xpe.setStaticContext(sc);
-            XPathVariable thisVar = sc.declareVariable("", contextVar);
+            XPathVariable thisVar = sc.declareVariable(NamespaceUri.of(""), contextVar);
             XPathExpression xpath = xpe.createExpression(path);
             XPathDynamicContext dc = xpath.createDynamicContext(null);
             dc.setContextItem(contextItem);
diff --git a/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXQuery.java b/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXQuery.java
index 623e6d710..043c8b06d 100644
--- a/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXQuery.java
+++ b/src/main/java/org/apache/xmlbeans/impl/xpath/saxon/SaxonXQuery.java
@@ -20,6 +20,7 @@
 import net.sf.saxon.dom.NodeOverNodeInfo;
 import net.sf.saxon.ma.map.HashTrieMap;
 import net.sf.saxon.om.Item;
+import net.sf.saxon.om.NamespaceUri;
 import net.sf.saxon.om.NodeInfo;
 import net.sf.saxon.om.StructuredQName;
 import net.sf.saxon.query.DynamicQueryContext;
@@ -81,7 +82,9 @@ public SaxonXQuery(final String query, String contextVar, Integer boundary, XmlO
         StaticQueryContext sc = config.newStaticQueryContext();
         Map<String, String> nsMap = xmlOptions.getLoadAdditionalNamespaces();
         if (nsMap != null) {
-            nsMap.forEach(sc::declareNamespace);
+            for (Map.Entry<String, String> entry : nsMap.entrySet()) {
+                sc.declareNamespace(entry.getKey(), NamespaceUri.of(entry.getValue()));
+            }
         }
         this.contextVar = contextVar;
         //Saxon requires external variables at the end of the prolog...
@@ -176,13 +179,14 @@ public List<Object> execQuery(Object node, Map<String,Object> variableBindings)
             DocumentWrapper docWrapper = new DocumentWrapper(dom, null, config);
             NodeInfo root = docWrapper.wrap(contextNode);
 
+            NamespaceUri emptyUri = NamespaceUri.of("");
             DynamicQueryContext dc = new DynamicQueryContext(config);
             dc.setContextItem(root);
-            dc.setParameter(new StructuredQName("", null, contextVar), root);
+            dc.setParameter(new StructuredQName("", emptyUri, contextVar), root);
             // Set the other variables
             if (variableBindings != null) {
                 for (Map.Entry<String, Object> me : variableBindings.entrySet()) {
-                    StructuredQName key = new StructuredQName("", null, me.getKey());
+                    StructuredQName key = new StructuredQName("", emptyUri, me.getKey());
                     Object value = me.getValue();
                     if (value instanceof XmlTokenSource) {
                         Node paramObject = ((XmlTokenSource) value).getDomNode();
@@ -282,7 +286,7 @@ private static Item objectToItem(Object value, Configuration config) throws XPat
             }
         } else if (value instanceof QName) {
             QName q = (QName) value;
-            return new QNameValue(q.getPrefix(), q.getNamespaceURI(), q.getLocalPart()); //BuiltInAtomicType.QNAME, null);
+            return new QNameValue(q.getPrefix(), NamespaceUri.of(q.getNamespaceURI()), q.getLocalPart()); //BuiltInAtomicType.QNAME, null);
         } else if (value instanceof URI) {
             return new AnyURIValue(value.toString());
         } else if (value instanceof Map) {
diff --git a/src/main/maven/org.apache.xmlbeans/xmlbeans/pom.xml b/src/main/maven/org.apache.xmlbeans/xmlbeans/pom.xml
index 553622ded..d756fa3dc 100644
--- a/src/main/maven/org.apache.xmlbeans/xmlbeans/pom.xml
+++ b/src/main/maven/org.apache.xmlbeans/xmlbeans/pom.xml
@@ -85,7 +85,7 @@
         <dependency>
             <groupId>net.sf.saxon</groupId>
             <artifactId>Saxon-HE</artifactId>
-            <version>11.5</version>
+            <version>12.3</version>
             <scope>provided</scope>
         </dependency>
         <dependency>
diff --git a/src/main/maven/plugin.xml b/src/main/maven/plugin.xml
index 371b4b4b9..702847fc1 100644
--- a/src/main/maven/plugin.xml
+++ b/src/main/maven/plugin.xml
@@ -409,7 +409,7 @@
         <dependency>
             <groupId>net.sf.saxon</groupId>
             <artifactId>Saxon-HE</artifactId>
-            <version>11.5</version>
+            <version>12.3</version>
         </dependency>
         <dependency>
             <groupId>com.github.javaparser</groupId>