diff --git a/include/exiv2/properties.hpp b/include/exiv2/properties.hpp
index 12f6fd35..1c51c0cc 100644
--- a/include/exiv2/properties.hpp
+++ b/include/exiv2/properties.hpp
@@ -65,19 +65,19 @@ struct EXIV2API XmpNsInfo {
 
 //! XMP property reference, implemented as a static class.
 class EXIV2API XmpProperties {
-  //! Prevent construction: not implemented.
-  XmpProperties();
-  //! Prevent copy-construction: not implemented.
-  XmpProperties(const XmpProperties& rhs);
-  //! Prevent assignment: not implemented.
-  XmpProperties& operator=(const XmpProperties& rhs);
-
  private:
   static const XmpNsInfo* nsInfoUnsafe(const std::string& prefix);
   static void unregisterNsUnsafe(const std::string& ns);
   static const XmpNsInfo* lookupNsRegistryUnsafe(const XmpNsInfo::Prefix& prefix);
 
  public:
+  //! Prevent construction: not implemented.
+  XmpProperties() = delete;
+  //! Prevent copy-construction: not implemented.
+  XmpProperties(const XmpProperties&) = delete;
+  //! Prevent assignment: not implemented.
+  XmpProperties& operator=(const XmpProperties& rhs) = delete;
+
   /*!
     @brief Return the title (label) of the property.
     @param key The property key