diff --git a/contrib/xml2/xpath.c b/contrib/xml2/xpath.c
index a692dc6be8..94641930f7 100644
--- a/contrib/xml2/xpath.c
+++ b/contrib/xml2/xpath.c
@@ -75,7 +75,6 @@ pgxml_parser_init(PgXmlStrictness strictness)
 	xmlInitParser();
 
 	xmlSubstituteEntitiesDefault(1);
-	xmlLoadExtDtdDefaultValue = 1;
 
 	return xmlerrcxt;
 }
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index 6411f56b99..aae0692586 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -65,6 +65,16 @@
 #if LIBXML_VERSION >= 20704
 #define HAVE_XMLSTRUCTUREDERRORCONTEXT 1
 #endif
+
+/*
+ * libxml2 2.12 decided to insert "const" into the error handler API.
+ */
+#if LIBXML_VERSION >= 21200
+#define PgXmlErrorPtr const xmlError *
+#else
+#define PgXmlErrorPtr xmlErrorPtr
+#endif
+
 #endif							/* USE_LIBXML */
 
 #include "access/htup_details.h"
@@ -119,7 +129,7 @@ struct PgXmlErrorContext
 
 static xmlParserInputPtr xmlPgEntityLoader(const char *URL, const char *ID,
 										   xmlParserCtxtPtr ctxt);
-static void xml_errorHandler(void *data, xmlErrorPtr error);
+static void xml_errorHandler(void *data, PgXmlErrorPtr error);
 static void xml_ereport_by_code(int level, int sqlcode,
 								const char *msg, int errcode);
 static void chopStringInfoNewlines(StringInfo str);
@@ -1749,7 +1759,7 @@ xml_ereport(PgXmlErrorContext *errcxt, int level, int sqlcode, const char *msg)
  * Error handler for libxml errors and warnings
  */
 static void
-xml_errorHandler(void *data, xmlErrorPtr error)
+xml_errorHandler(void *data, PgXmlErrorPtr error)
 {
 	PgXmlErrorContext *xmlerrcxt = (PgXmlErrorContext *) data;
 	xmlParserCtxtPtr ctxt = (xmlParserCtxtPtr) error->ctxt;