diff --git a/src/App/Metadata.cpp b/src/App/Metadata.cpp
index 6a2ef316de..53785699df 100644
--- a/src/App/Metadata.cpp
+++ b/src/App/Metadata.cpp
@@ -57,13 +57,8 @@ directly. If you did not intend to use a system-defined macro
 #endif
 
 using namespace App;
-namespace fs = std::filesystem;
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-#define XERCES_CPP_NAMESPACE_QUALIFIER
 using namespace XERCES_CPP_NAMESPACE;
-#else
-XERCES_CPP_NAMESPACE_USE
-#endif
+namespace fs = std::filesystem;
 
 namespace MetadataInternal
 {
diff --git a/src/App/MetadataPyImp.cpp b/src/App/MetadataPyImp.cpp
index 8776607ea3..55ef491639 100644
--- a/src/App/MetadataPyImp.cpp
+++ b/src/App/MetadataPyImp.cpp
@@ -33,12 +33,7 @@
 #include "MetadataPy.cpp"
 
 using namespace Base;
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-#define XERCES_CPP_NAMESPACE_QUALIFIER
 using namespace XERCES_CPP_NAMESPACE;
-#else
-XERCES_CPP_NAMESPACE_USE
-#endif
 
 // Returns a string which represents the object e.g. when printed in Python
 std::string MetadataPy::representation() const
diff --git a/src/App/ProjectFile.cpp b/src/App/ProjectFile.cpp
index 142d92bd08..38cc61f582 100644
--- a/src/App/ProjectFile.cpp
+++ b/src/App/ProjectFile.cpp
@@ -55,13 +55,8 @@
 #include <Base/Stream.h>
 #include <Base/XMLTools.h>
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-#define XERCES_CPP_NAMESPACE_QUALIFIER
-using namespace XERCES_CPP_NAMESPACE;
-#else
-XERCES_CPP_NAMESPACE_USE
-#endif
 using namespace App;
+using namespace XERCES_CPP_NAMESPACE;
 
 namespace
 {
@@ -88,7 +83,7 @@ public:
 class DocumentMetadata
 {
 public:
-    explicit DocumentMetadata(XERCES_CPP_NAMESPACE_QUALIFIER DOMDocument* xmlDocument)
+    explicit DocumentMetadata(XERCES_CPP_NAMESPACE::DOMDocument* xmlDocument)
         : xmlDocument {xmlDocument}
     {}
 
@@ -199,7 +194,7 @@ private:
     }
 
 private:
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMDocument* xmlDocument;
+    XERCES_CPP_NAMESPACE::DOMDocument* xmlDocument;
     ProjectFile::Metadata metadata;
 };
 }  // namespace
@@ -449,7 +444,7 @@ std::list<ProjectFile::PropertyFile> ProjectFile::getPropertyFiles(const std::st
     return files;
 }
 
-void ProjectFile::findFiles(XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* node,
+void ProjectFile::findFiles(XERCES_CPP_NAMESPACE::DOMNode* node,
                             std::list<ProjectFile::PropertyFile>& files) const
 {
     if (node->hasAttributes()) {
@@ -528,7 +523,7 @@ std::list<std::string> ProjectFile::getInputFiles(const std::string& name) const
     return files;
 }
 
-void ProjectFile::findFiles(XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* node,
+void ProjectFile::findFiles(XERCES_CPP_NAMESPACE::DOMNode* node,
                             std::list<std::string>& files) const
 {
     if (node->hasAttributes()) {
diff --git a/src/App/ProjectFile.h b/src/App/ProjectFile.h
index b9086c8d12..a9c160f721 100644
--- a/src/App/ProjectFile.h
+++ b/src/App/ProjectFile.h
@@ -32,22 +32,12 @@
 #include <string>
 #include <xercesc/util/XercesDefs.hpp>
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-#define XERCES_CPP_NAMESPACE_QUALIFIER
-using namespace XERCES_CPP_NAMESPACE;
 namespace XERCES_CPP_NAMESPACE
 {
 class DOMNode;
 class DOMElement;
 class DOMDocument;
 }  // namespace XERCES_CPP_NAMESPACE
-#else
-XERCES_CPP_NAMESPACE_BEGIN
-class DOMDocument;
-class DOMElement;
-class DOMNode;
-XERCES_CPP_NAMESPACE_END
-#endif
 
 namespace App
 {
@@ -206,12 +196,12 @@ public:
     bool replaceProjectFile(const std::string& name, bool keepfile = false);
 
 private:
-    void findFiles(XERCES_CPP_NAMESPACE_QUALIFIER DOMNode*, std::list<std::string>&) const;
-    void findFiles(XERCES_CPP_NAMESPACE_QUALIFIER DOMNode*, std::list<PropertyFile>&) const;
+    void findFiles(XERCES_CPP_NAMESPACE::DOMNode*, std::list<std::string>&) const;
+    void findFiles(XERCES_CPP_NAMESPACE::DOMNode*, std::list<PropertyFile>&) const;
 
 private:
     std::string stdFile;
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMDocument* xmlDocument;
+    XERCES_CPP_NAMESPACE::DOMDocument* xmlDocument;
 };
 
 
diff --git a/src/Base/InputSource.cpp b/src/Base/InputSource.cpp
index 19cfa8f8bb..644e2b1303 100644
--- a/src/Base/InputSource.cpp
+++ b/src/Base/InputSource.cpp
@@ -36,13 +36,6 @@
 #include "InputSource.h"
 #include "XMLTools.h"
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
-using namespace XERCES_CPP_NAMESPACE;
-#else
-XERCES_CPP_NAMESPACE_USE
-#endif
-
 using namespace Base;
 using namespace std;
 
@@ -113,10 +106,7 @@ struct StdInputStream::TextCodec
 };
 #endif
 
-StdInputStream::StdInputStream(
-    std::istream& Stream,
-    XERCES_CPP_NAMESPACE_QUALIFIER MemoryManager* const manager
-)
+StdInputStream::StdInputStream(std::istream& Stream, XERCES_CPP_NAMESPACE::MemoryManager* const manager)
     : stream(Stream)
     , codec(new TextCodec)
 {
@@ -157,7 +147,7 @@ XMLSize_t StdInputStream::readBytes(XMLByte* const toFill, const XMLSize_t maxTo
 StdInputSource::StdInputSource(
     std::istream& Stream,
     const char* filePath,
-    XERCES_CPP_NAMESPACE_QUALIFIER MemoryManager* const manager
+    XERCES_CPP_NAMESPACE::MemoryManager* const manager
 )
     : InputSource(manager)
     , stream(Stream)
@@ -174,7 +164,7 @@ StdInputSource::~StdInputSource() = default;
 // ---------------------------------------------------------------------------
 //  StdInputSource: InputSource interface implementation
 // ---------------------------------------------------------------------------
-BinInputStream* StdInputSource::makeStream() const
+XERCES_CPP_NAMESPACE::BinInputStream* StdInputSource::makeStream() const
 {
     StdInputStream* retStrm = new StdInputStream(stream /*, getMemoryManager()*/);
     return retStrm;
diff --git a/src/Base/InputSource.h b/src/Base/InputSource.h
index 3144802625..c7afa8d897 100644
--- a/src/Base/InputSource.h
+++ b/src/Base/InputSource.h
@@ -34,29 +34,22 @@
 # include <FCGlobal.h>
 #endif
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
 namespace XERCES_CPP_NAMESPACE
 {
 class BinInputStream;
 }
-#else
-XERCES_CPP_NAMESPACE_BEGIN
-class BinInputStream;
-XERCES_CPP_NAMESPACE_END
-#endif
 
 namespace Base
 {
 
 
-class BaseExport StdInputStream: public XERCES_CPP_NAMESPACE_QUALIFIER BinInputStream
+class BaseExport StdInputStream: public XERCES_CPP_NAMESPACE::BinInputStream
 {
 public:
     // clang-format off
     explicit StdInputStream(std::istream& Stream,
-                   XERCES_CPP_NAMESPACE_QUALIFIER MemoryManager* const manager =
-                   XERCES_CPP_NAMESPACE_QUALIFIER XMLPlatformUtils::fgMemoryManager);
+                   XERCES_CPP_NAMESPACE::MemoryManager* const manager =
+                   XERCES_CPP_NAMESPACE::XMLPlatformUtils::fgMemoryManager);
     ~StdInputStream() override;
     // clang-format on
 
@@ -92,18 +85,18 @@ private:
 };
 
 
-class BaseExport StdInputSource: public XERCES_CPP_NAMESPACE_QUALIFIER InputSource
+class BaseExport StdInputSource: public XERCES_CPP_NAMESPACE::InputSource
 {
 public:
     StdInputSource(
         std::istream& Stream,
         const char* filePath,
-        XERCES_CPP_NAMESPACE_QUALIFIER MemoryManager* const manager
-        = XERCES_CPP_NAMESPACE_QUALIFIER XMLPlatformUtils::fgMemoryManager
+        XERCES_CPP_NAMESPACE::MemoryManager* const manager
+        = XERCES_CPP_NAMESPACE::XMLPlatformUtils::fgMemoryManager
     );
     ~StdInputSource() override;
 
-    XERCES_CPP_NAMESPACE_QUALIFIER BinInputStream* makeStream() const override;
+    XERCES_CPP_NAMESPACE::BinInputStream* makeStream() const override;
 
     StdInputSource(const StdInputSource&) = delete;
     StdInputSource(StdInputSource&&) = delete;
diff --git a/src/Base/Parameter.cpp b/src/Base/Parameter.cpp
index 75c7a52c1e..c98e71085f 100644
--- a/src/Base/Parameter.cpp
+++ b/src/Base/Parameter.cpp
@@ -61,12 +61,7 @@
 
 FC_LOG_LEVEL_INIT("Parameter", true, true)
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
 using namespace XERCES_CPP_NAMESPACE;
-#else
-XERCES_CPP_NAMESPACE_USE
-#endif
 using namespace Base;
 
 
@@ -122,7 +117,7 @@ public:
     //@{
 
     /** @ interface from DOMWriterFilter */
-    FilterAction acceptNode(const XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* node) const override;
+    FilterAction acceptNode(const DOMNode* node) const override;
     //@{
 
     ShowType getWhatToShow() const override
@@ -176,11 +171,7 @@ inline bool DOMTreeErrorReporter::getSawErrors() const
 
 /** Default construction
  */
-ParameterGrp::ParameterGrp(
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* GroupNode,
-    const char* sName,
-    ParameterGrp* Parent
-)
+ParameterGrp::ParameterGrp(DOMElement* GroupNode, const char* sName, ParameterGrp* Parent)
     : _pGroupNode(GroupNode)
     , _Parent(Parent)
 {
@@ -360,11 +351,7 @@ void ParameterGrp::revert(const Base::Reference<ParameterGrp>& Grp)
     }
 }
 
-XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::CreateElement(
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* Start,
-    const char* Type,
-    const char* Name
-)
+DOMElement* ParameterGrp::CreateElement(DOMElement* Start, const char* Type, const char* Name)
 {
     if (XMLString::compareString(Start->getNodeName(), XStrLiteral("FCParamGroup").unicodeForm()) != 0
         && XMLString::compareString(Start->getNodeName(), XStrLiteral("FCParameters").unicodeForm())
@@ -383,7 +370,7 @@ XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::CreateElement(
         _Parent->_GetGroup(_cName.c_str());
     }
 
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMDocument* pDocument = Start->getOwnerDocument();
+    DOMDocument* pDocument = Start->getOwnerDocument();
 
     auto pcElem = pDocument->createElement(XStr(Type).unicodeForm());
     pcElem->setAttribute(XStrLiteral("Name").unicodeForm(), XStr(Name).unicodeForm());
@@ -1058,7 +1045,7 @@ void ParameterGrp::SetASCII(const char* Name, const char* sValue)
         // and set the value
         DOMNode* pcElem2 = pcElem->getFirstChild();
         if (!pcElem2) {
-            XERCES_CPP_NAMESPACE_QUALIFIER DOMDocument* pDocument = _pGroupNode->getOwnerDocument();
+            DOMDocument* pDocument = _pGroupNode->getOwnerDocument();
             DOMText* pText = pDocument->createTextNode(XUTF8Str(sValue).unicodeForm());
             pcElem->appendChild(pText);
             if (isNew || sValue[0] != 0) {
@@ -1453,11 +1440,7 @@ bool ParameterGrp::ShouldRemove() const
     });
 }
 
-XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::FindElement(
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* Start,
-    const char* Type,
-    const char* Name
-) const
+DOMElement* ParameterGrp::FindElement(DOMElement* Start, const char* Type, const char* Name) const
 {
     if (XMLString::compareString(Start->getNodeName(), XStrLiteral("FCParamGroup").unicodeForm()) != 0
         && XMLString::compareString(Start->getNodeName(), XStrLiteral("FCParameters").unicodeForm())
@@ -1496,10 +1479,7 @@ XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::FindElement(
     return nullptr;
 }
 
-XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::FindNextElement(
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* Prev,
-    const char* Type
-) const
+DOMElement* ParameterGrp::FindNextElement(DOMNode* Prev, const char* Type) const
 {
     DOMNode* clChild = Prev;
     if (!clChild) {
@@ -1518,11 +1498,7 @@ XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::FindNextElement(
     return nullptr;
 }
 
-XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::FindOrCreateElement(
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* Start,
-    const char* Type,
-    const char* Name
-)
+DOMElement* ParameterGrp::FindOrCreateElement(DOMElement* Start, const char* Type, const char* Name)
 {
     // first try to find it
     DOMElement* pcElem = FindElement(Start, Type, Name);
@@ -1533,10 +1509,7 @@ XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* ParameterGrp::FindOrCreateElement(
     return CreateElement(Start, Type, Name);
 }
 
-XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* ParameterGrp::FindAttribute(
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* Node,
-    const char* Name
-) const
+DOMNode* ParameterGrp::FindAttribute(DOMNode* Node, const char* Name) const
 {
     DOMNamedNodeMap* attr = Node->getAttributes();
     if (attr) {
@@ -1881,7 +1854,7 @@ int ParameterManager::LoadDocument(const char* sFileName)
     }
 }
 
-class NoOpEntityResolver: public XERCES_CPP_NAMESPACE_QUALIFIER EntityResolver
+class NoOpEntityResolver: public EntityResolver
 {
 public:
     InputSource* resolveEntity(const XMLCh* const publicId, const XMLCh* const systemId) override
@@ -1892,7 +1865,7 @@ public:
     }
 };
 
-int ParameterManager::LoadDocument(const XERCES_CPP_NAMESPACE_QUALIFIER InputSource& inputSource)
+int ParameterManager::LoadDocument(const XERCES_CPP_NAMESPACE::InputSource& inputSource)
 {
     //
     //  Create our parser, then attach an error handler to the parser.
diff --git a/src/Base/Parameter.h b/src/Base/Parameter.h
index 4b16b4ddd4..5d5a952939 100644
--- a/src/Base/Parameter.h
+++ b/src/Base/Parameter.h
@@ -66,8 +66,6 @@ using PyObject = struct _object;
 # pragma warning(disable : 4275)
 #endif
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
 namespace XERCES_CPP_NAMESPACE
 {
 class DOMNode;
@@ -76,15 +74,6 @@ class DOMDocument;
 class XMLFormatTarget;
 class InputSource;
 }  // namespace XERCES_CPP_NAMESPACE
-#else
-XERCES_CPP_NAMESPACE_BEGIN
-class DOMNode;
-class DOMElement;
-class DOMDocument;
-class XMLFormatTarget;
-class InputSource;
-XERCES_CPP_NAMESPACE_END
-#endif
 
 class ParameterManager;
 
@@ -438,7 +427,7 @@ public:
 protected:
     /// constructor is protected (handle concept)
     ParameterGrp(
-        XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* GroupNode = nullptr,
+        XERCES_CPP_NAMESPACE::DOMElement* GroupNode = nullptr,
         const char* sName = nullptr,
         ParameterGrp* Parent = nullptr
     );
@@ -453,8 +442,8 @@ protected:
     void _SetAttribute(ParamType Type, const char* Name, const char* Value);
     void _Notify(ParamType Type, const char* Name, const char* Value);
 
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* FindNextElement(
-        XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* Prev,
+    XERCES_CPP_NAMESPACE::DOMElement* FindNextElement(
+        XERCES_CPP_NAMESPACE::DOMNode* Prev,
         const char* Type
     ) const;
 
@@ -464,8 +453,8 @@ protected:
      *  the pointer to that element, otherwise NULL
      *  If the names not given it returns the first occurrence of Type.
      */
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* FindElement(
-        XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* Start,
+    XERCES_CPP_NAMESPACE::DOMElement* FindElement(
+        XERCES_CPP_NAMESPACE::DOMElement* Start,
         const char* Type,
         const char* Name = nullptr
     ) const;
@@ -475,27 +464,27 @@ protected:
      *  element of Type and with the attribute Name=Name. On success it returns
      *  the pointer to that element, otherwise it creates the element and returns the pointer.
      */
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* FindOrCreateElement(
-        XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* Start,
+    XERCES_CPP_NAMESPACE::DOMElement* FindOrCreateElement(
+        XERCES_CPP_NAMESPACE::DOMElement* Start,
         const char* Type,
         const char* Name
     );
 
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* CreateElement(
-        XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* Start,
+    XERCES_CPP_NAMESPACE::DOMElement* CreateElement(
+        XERCES_CPP_NAMESPACE::DOMElement* Start,
         const char* Type,
         const char* Name
     );
 
     /** Find an attribute specified by Name
      */
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* FindAttribute(
-        XERCES_CPP_NAMESPACE_QUALIFIER DOMNode* Node,
+    XERCES_CPP_NAMESPACE::DOMNode* FindAttribute(
+        XERCES_CPP_NAMESPACE::DOMNode* Node,
         const char* Name
     ) const;
 
     /// DOM Node of the Base node of this group
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMElement* _pGroupNode;
+    XERCES_CPP_NAMESPACE::DOMElement* _pGroupNode;
     /// the own name
     std::string _cName;
     /// map of already exported groups
@@ -581,10 +570,10 @@ public:
         signalParamChanged;
 
     int LoadDocument(const char* sFileName);
-    int LoadDocument(const XERCES_CPP_NAMESPACE_QUALIFIER InputSource&);
+    int LoadDocument(const XERCES_CPP_NAMESPACE::InputSource&);
     bool LoadOrCreateDocument(const char* sFileName);
     void SaveDocument(const char* sFileName) const;
-    void SaveDocument(XERCES_CPP_NAMESPACE_QUALIFIER XMLFormatTarget* pFormatTarget) const;
+    void SaveDocument(XERCES_CPP_NAMESPACE::XMLFormatTarget* pFormatTarget) const;
     void CreateDocument();
     void CheckDocument() const;
 
@@ -607,7 +596,7 @@ public:
     //@}
 
 private:
-    XERCES_CPP_NAMESPACE_QUALIFIER DOMDocument* _pDocument {nullptr};
+    XERCES_CPP_NAMESPACE::DOMDocument* _pDocument {nullptr};
     ParameterSerializer* paramSerializer {nullptr};
 
     bool gIgnoreSave;
diff --git a/src/Base/Reader.cpp b/src/Base/Reader.cpp
index b80fbaedc5..43b9e44c0f 100644
--- a/src/Base/Reader.cpp
+++ b/src/Base/Reader.cpp
@@ -48,14 +48,8 @@
 #include <zipios++/zipinputstream.h>
 #include <boost/iostreams/filtering_stream.hpp>
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
-using namespace XERCES_CPP_NAMESPACE;
-#else
-XERCES_CPP_NAMESPACE_USE
-#endif
-
 using namespace std;
+using namespace XERCES_CPP_NAMESPACE;
 
 
 // ---------------------------------------------------------------------------
@@ -570,7 +564,7 @@ void Base::XMLReader::startElement(
     const XMLCh* const /*uri*/,
     const XMLCh* const localname,
     const XMLCh* const /*qname*/,
-    const XERCES_CPP_NAMESPACE_QUALIFIER Attributes& attrs
+    const XERCES_CPP_NAMESPACE::Attributes& attrs
 )
 {
     Level++;  // new scope
@@ -632,7 +626,7 @@ void Base::XMLReader::resetDocument()
 // ---------------------------------------------------------------------------
 //  Base::XMLReader: Overrides of the SAX ErrorHandler interface
 // ---------------------------------------------------------------------------
-void Base::XMLReader::error(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseException& e)
+void Base::XMLReader::error(const XERCES_CPP_NAMESPACE::SAXParseException& e)
 {
     // print some details to error output and throw an
     // exception to abort the parsing
@@ -641,7 +635,7 @@ void Base::XMLReader::error(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseExcepti
     throw e;
 }
 
-void Base::XMLReader::fatalError(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseException& e)
+void Base::XMLReader::fatalError(const XERCES_CPP_NAMESPACE::SAXParseException& e)
 {
     // print some details to error output and throw an
     // exception to abort the parsing
@@ -650,7 +644,7 @@ void Base::XMLReader::fatalError(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseEx
     throw e;
 }
 
-void Base::XMLReader::warning(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseException& e)
+void Base::XMLReader::warning(const XERCES_CPP_NAMESPACE::SAXParseException& e)
 {
     // print some details to error output and throw an
     // exception to abort the parsing
diff --git a/src/Base/Reader.h b/src/Base/Reader.h
index 2b6be93143..2e7717ed7e 100644
--- a/src/Base/Reader.h
+++ b/src/Base/Reader.h
@@ -43,21 +43,13 @@ namespace zipios
 {
 class ZipInputStream;
 }
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
+
 namespace XERCES_CPP_NAMESPACE
 {
 class Attributes;
 class DefaultHandler;
 class SAX2XMLReader;
 }  // namespace XERCES_CPP_NAMESPACE
-#else
-XERCES_CPP_NAMESPACE_BEGIN
-class Attributes;
-class DefaultHandler;
-class SAX2XMLReader;
-XERCES_CPP_NAMESPACE_END
-#endif
 
 namespace Base
 {
@@ -128,7 +120,7 @@ void PropertyContainer::Restore(Base::Reader &reader)
  * \see Base::Persistence
  * \author Juergen Riegel
  */
-class BaseExport XMLReader: public XERCES_CPP_NAMESPACE_QUALIFIER DefaultHandler
+class BaseExport XMLReader: public XERCES_CPP_NAMESPACE::DefaultHandler
 {
 public:
     enum ReaderStatus
@@ -332,7 +324,7 @@ protected:
         const XMLCh* const uri,
         const XMLCh* const localname,
         const XMLCh* const qname,
-        const XERCES_CPP_NAMESPACE_QUALIFIER Attributes& attrs
+        const XERCES_CPP_NAMESPACE::Attributes& attrs
     ) override;
     void endElement(const XMLCh* const uri, const XMLCh* const localname, const XMLCh* const qname) override;
     void characters(const XMLCh* const chars, const XMLSize_t length) override;
@@ -356,9 +348,9 @@ protected:
     // -----------------------------------------------------------------------
     /** @name Error handler */
     //@{
-    void warning(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseException& exc) override;
-    void error(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseException& exc) override;
-    void fatalError(const XERCES_CPP_NAMESPACE_QUALIFIER SAXParseException& exc) override;
+    void warning(const XERCES_CPP_NAMESPACE::SAXParseException& exc) override;
+    void error(const XERCES_CPP_NAMESPACE::SAXParseException& exc) override;
+    void fatalError(const XERCES_CPP_NAMESPACE::SAXParseException& exc) override;
     void resetErrors() override;
     //@}
 
@@ -387,8 +379,8 @@ private:
 
 
     FileInfo _File;
-    XERCES_CPP_NAMESPACE_QUALIFIER SAX2XMLReader* parser;
-    XERCES_CPP_NAMESPACE_QUALIFIER XMLPScanToken token;
+    XERCES_CPP_NAMESPACE::SAX2XMLReader* parser;
+    XERCES_CPP_NAMESPACE::XMLPScanToken token;
     bool _valid {false};
     bool _verbose {true};
 
diff --git a/src/Base/XMLTools.cpp b/src/Base/XMLTools.cpp
index 1f76cc55dc..0d0e03497f 100644
--- a/src/Base/XMLTools.cpp
+++ b/src/Base/XMLTools.cpp
@@ -28,13 +28,7 @@
 #include "Exception.h"
 #include "XMLTools.h"
 
-
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
 using namespace XERCES_CPP_NAMESPACE;
-#else
-XERCES_CPP_NAMESPACE_USE
-#endif
 
 std::unique_ptr<XMLTranscoder> XMLTools::transcoder;  // NOLINT
 
diff --git a/src/Base/XMLTools.h b/src/Base/XMLTools.h
index 066174baa1..14fadabbac 100644
--- a/src/Base/XMLTools.h
+++ b/src/Base/XMLTools.h
@@ -34,21 +34,12 @@
 
 #include <FCGlobal.h>
 
-#ifndef XERCES_CPP_NAMESPACE_BEGIN
-# define XERCES_CPP_NAMESPACE_QUALIFIER
 namespace XERCES_CPP_NAMESPACE
 {
 class DOMNode;
 class DOMElement;
 class DOMDocument;
 }  // namespace XERCES_CPP_NAMESPACE
-#else
-XERCES_CPP_NAMESPACE_BEGIN
-class DOMNode;
-class DOMElement;
-class DOMDocument;
-XERCES_CPP_NAMESPACE_END
-#endif
 
 // Helper class
 class BaseExport XMLTools
@@ -107,12 +98,12 @@ inline std::ostream& operator<<(std::ostream& target, const StrX& toDump)
 }
 
 inline StrX::StrX(const XMLCh* const toTranscode)
-    : fLocalForm(XERCES_CPP_NAMESPACE_QUALIFIER XMLString::transcode(toTranscode))
+    : fLocalForm(XERCES_CPP_NAMESPACE::XMLString::transcode(toTranscode))
 {}
 
 inline StrX::~StrX()
 {
-    XERCES_CPP_NAMESPACE_QUALIFIER XMLString::release(&fLocalForm);
+    XERCES_CPP_NAMESPACE::XMLString::release(&fLocalForm);
 }
 
 
@@ -171,7 +162,7 @@ class XStr
 public:
     ///  Constructors and Destructor
     explicit XStr(const char* const toTranscode);
-    explicit XStr(const char* const toTranscode, XERCES_CPP_NAMESPACE_QUALIFIER MemoryManager* memMgr);
+    explicit XStr(const char* const toTranscode, XERCES_CPP_NAMESPACE::MemoryManager* memMgr);
     ~XStr();
 
 
@@ -182,22 +173,22 @@ public:
 private:
     /// This is the Unicode XMLCh format of the string.
     XMLCh* fUnicodeForm;
-    XERCES_CPP_NAMESPACE_QUALIFIER MemoryManager* memMgr;
+    XERCES_CPP_NAMESPACE::MemoryManager* memMgr;
 };
 
 
 inline XStr::XStr(const char* const toTranscode)
-    : XStr(toTranscode, XERCES_CPP_NAMESPACE_QUALIFIER XMLPlatformUtils::fgMemoryManager)
+    : XStr(toTranscode, XERCES_CPP_NAMESPACE::XMLPlatformUtils::fgMemoryManager)
 {}
 
 inline XStr::XStr(const char* const toTranscode, XERCES_CPP_NAMESPACE_QUALIFIER MemoryManager* memMgr)
-    : fUnicodeForm(XERCES_CPP_NAMESPACE_QUALIFIER XMLString::transcode(toTranscode, memMgr))
+    : fUnicodeForm(XERCES_CPP_NAMESPACE::XMLString::transcode(toTranscode, memMgr))
     , memMgr(memMgr)
 {}
 
 inline XStr::~XStr()
 {
-    XERCES_CPP_NAMESPACE_QUALIFIER XMLString::release(&fUnicodeForm, memMgr);
+    XERCES_CPP_NAMESPACE::XMLString::release(&fUnicodeForm, memMgr);
 }
 
 // Uses the compiler to create a cache of transcoded string literals so that each subsequent call
diff --git a/src/Gui/ApplicationPy.cpp b/src/Gui/ApplicationPy.cpp
index 8dc2373baf..a93b009774 100644
--- a/src/Gui/ApplicationPy.cpp
+++ b/src/Gui/ApplicationPy.cpp
@@ -1123,14 +1123,14 @@ PyObject* ApplicationPy::sActivateWorkbenchHandler(PyObject* /*self*/, PyObject*
         PyErr_SetString(e.getPyExceptionType(), err.str().c_str());
         return nullptr;
     }
-    catch (const XERCES_CPP_NAMESPACE_QUALIFIER TranscodingException& e) {
+    catch (const XERCES_CPP_NAMESPACE::TranscodingException& e) {
         std::stringstream err;
-        char* pMsg = XERCES_CPP_NAMESPACE_QUALIFIER XMLString::transcode(e.getMessage());
+        char* pMsg = XERCES_CPP_NAMESPACE::XMLString::transcode(e.getMessage());
         err << "Transcoding exception in Xerces-c:\n\n"
             << "Transcoding exception raised in activateWorkbench.\n"
             << "Check if your user configuration file is valid.\n"
             << "  Exception message:" << pMsg;
-        XERCES_CPP_NAMESPACE_QUALIFIER XMLString::release(&pMsg);
+        XERCES_CPP_NAMESPACE::XMLString::release(&pMsg);
         PyErr_SetString(PyExc_RuntimeError, err.str().c_str());
         return nullptr;
     }