diff --git a/src/pugixml.hpp b/src/pugixml.hpp
index eb2abff4..2526fe3c 100644
--- a/src/pugixml.hpp
+++ b/src/pugixml.hpp
@@ -141,13 +141,13 @@
 #endif
 
 // If C++ is 2011 or higher, add 'constexpr' qualifiers
-#ifndef PUGIXML_CONSTEXPR
+#ifndef PUGIXML_CONSTEXPR11
 #	if __cplusplus >= 201103
-#		define PUGIXML_CONSTEXPR constexpr
+#		define PUGIXML_CONSTEXPR11 constexpr
 #	elif defined(_MSC_VER) && _MSC_VER >= 1910
-#		define PUGIXML_CONSTEXPR constexpr
+#		define PUGIXML_CONSTEXPR11 constexpr
 #	else
-#		define PUGIXML_CONSTEXPR const
+#		define PUGIXML_CONSTEXPR11 const
 #	endif
 #endif
 
@@ -155,9 +155,9 @@
 // required for C++20 module
 #ifndef PUGIXML_CONSTANT
 #	if __cplusplus >= 201703
-#		define PUGIXML_CONSTANT inline PUGIXML_CONSTEXPR
+#		define PUGIXML_CONSTANT inline PUGIXML_CONSTEXPR11
 #	else
-#		define PUGIXML_CONSTANT PUGIXML_CONSTEXPR
+#		define PUGIXML_CONSTANT PUGIXML_CONSTEXPR11
 #	endif
 #endif