diff --git a/UPGRADING.INTERNALS b/UPGRADING.INTERNALS
index ffdae3701aa..e435e35add7 100644
--- a/UPGRADING.INTERNALS
+++ b/UPGRADING.INTERNALS
@@ -147,6 +147,8 @@ PHP 8.4 INTERNALS UPGRADE NOTES
    - php_dom_create_object() now no longer accepts a NULL obj argument.
    - Removed the `ret` argument from the DOM_RET_OBJ macro, use the return
      value instead.
+   - Removed DOM_XMLNS_NAMESPACE from xml_common.h. Use DOM_XMLNS_NS_URI
+     from namespace_compat.h instead.
 
  b. ext/random
    - The macro RAND_RANGE_BADSCALING() has been removed. The implementation
diff --git a/ext/dom/element.c b/ext/dom/element.c
index bcd7fa38d18..d553f6fd634 100644
--- a/ext/dom/element.c
+++ b/ext/dom/element.c
@@ -814,7 +814,7 @@ static const xmlChar *dom_get_attribute_ns(dom_object *intern, xmlNodePtr elemp,
 		*should_free_result = true;
 		return strattr;
 	} else {
-		if (!follow_spec && xmlStrEqual(BAD_CAST uri, BAD_CAST DOM_XMLNS_NAMESPACE)) {
+		if (!follow_spec && xmlStrEqual(BAD_CAST uri, BAD_CAST DOM_XMLNS_NS_URI)) {
 			xmlNsPtr nsptr = dom_get_nsdecl(elemp, BAD_CAST name);
 			if (nsptr != NULL) {
 				return nsptr->href;
@@ -887,7 +887,7 @@ static void dom_set_attribute_ns_legacy(dom_object *intern, xmlNodePtr elemp, ch
 
 			if ((xmlStrEqual(BAD_CAST prefix, BAD_CAST "xmlns") ||
 				(prefix == NULL && xmlStrEqual(BAD_CAST localname, BAD_CAST "xmlns"))) &&
-				xmlStrEqual(BAD_CAST uri, BAD_CAST DOM_XMLNS_NAMESPACE)) {
+				xmlStrEqual(BAD_CAST uri, BAD_CAST DOM_XMLNS_NS_URI)) {
 				is_xmlns = 1;
 				if (prefix == NULL) {
 					nsptr = dom_get_nsdecl(elemp, NULL);
@@ -1152,7 +1152,7 @@ PHP_METHOD(DOMElement, getAttributeNodeNS)
 	attrp = xmlHasNsProp(elemp, BAD_CAST name, BAD_CAST uri);
 
 	if (attrp == NULL) {
-		if (!follow_spec && xmlStrEqual(BAD_CAST uri, DOM_XMLNS_NAMESPACE)) {
+		if (!follow_spec && xmlStrEqual(BAD_CAST uri, BAD_CAST DOM_XMLNS_NS_URI)) {
 			xmlNsPtr nsptr;
 			nsptr = dom_get_nsdecl(elemp, BAD_CAST name);
 			if (nsptr != NULL) {
diff --git a/ext/dom/node.c b/ext/dom/node.c
index 561ec8b576d..abda6cccce9 100644
--- a/ext/dom/node.c
+++ b/ext/dom/node.c
@@ -723,7 +723,7 @@ zend_result dom_node_prefix_write(dom_object *obj, zval *newval)
 				if (strURI == NULL ||
 					(zend_string_equals_literal(prefix_str, "xml") && strcmp(strURI, (char *) XML_XML_NAMESPACE)) ||
 					(nodep->type == XML_ATTRIBUTE_NODE && zend_string_equals_literal(prefix_str, "xmlns") &&
-					 strcmp(strURI, (char *) DOM_XMLNS_NAMESPACE)) ||
+					 strcmp(strURI, DOM_XMLNS_NS_URI)) ||
 					(nodep->type == XML_ATTRIBUTE_NODE && !strcmp((char *) nodep->name, "xmlns"))) {
 					php_dom_throw_error(NAMESPACE_ERR, dom_get_strict_error(obj->document));
 					return FAILURE;
diff --git a/ext/dom/php_dom.c b/ext/dom/php_dom.c
index 450c2a55c63..711ea29d125 100644
--- a/ext/dom/php_dom.c
+++ b/ext/dom/php_dom.c
@@ -2066,8 +2066,8 @@ xmlNsPtr dom_get_ns(xmlNodePtr nodep, char *uri, int *errorcode, char *prefix) {
 	xmlNsPtr nsptr;
 
 	if (! ((prefix && !strcmp (prefix, "xml") && strcmp(uri, (char *)XML_XML_NAMESPACE)) ||
-		   (prefix && !strcmp (prefix, "xmlns") && strcmp(uri, (char *)DOM_XMLNS_NAMESPACE)) ||
-		   (prefix && !strcmp(uri, (char *)DOM_XMLNS_NAMESPACE) && strcmp (prefix, "xmlns")))) {
+		   (prefix && !strcmp (prefix, "xmlns") && strcmp(uri, DOM_XMLNS_NS_URI)) ||
+		   (prefix && !strcmp(uri, DOM_XMLNS_NS_URI) && strcmp (prefix, "xmlns")))) {
 		nsptr = dom_get_ns_unchecked(nodep, uri, prefix);
 		if (UNEXPECTED(nsptr == NULL)) {
 			goto err;
diff --git a/ext/dom/xml_common.h b/ext/dom/xml_common.h
index fb1760d25c3..e93767ebc84 100644
--- a/ext/dom/xml_common.h
+++ b/ext/dom/xml_common.h
@@ -56,9 +56,6 @@ PHP_DOM_EXPORT dom_object *php_dom_object_get_data(xmlNodePtr obj);
 PHP_DOM_EXPORT bool php_dom_create_object(xmlNodePtr obj, zval* return_value, dom_object *domobj);
 PHP_DOM_EXPORT xmlNodePtr dom_object_get_node(dom_object *obj);
 
-#define DOM_XMLNS_NAMESPACE \
-    (const xmlChar *) "http://www.w3.org/2000/xmlns/"
-
 #define NODE_GET_OBJ(__ptr, __id, __prtype, __intern) { \
 	__intern = Z_LIBXML_NODE_P(__id); \
 	if (UNEXPECTED(__intern->node == NULL)) { \