diff --git a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/StreamHelper.java b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/StreamHelper.java
index 39eee4d1d3b..c8d32ce4a4e 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/StreamHelper.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/openxml4j/opc/StreamHelper.java
@@ -24,16 +24,17 @@ Licensed to the Apache Software Foundation (ASF) under one or more
 
 import javax.xml.transform.OutputKeys;
 import javax.xml.transform.Result;
-import javax.xml.transform.Source;
 import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerException;
 import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.stream.StreamResult;
 
 import org.apache.poi.util.IOUtils;
+import org.apache.poi.util.Internal;
 import org.apache.poi.util.XMLHelper;
 import org.w3c.dom.Document;
 
+@Internal
 public final class StreamHelper {
 
     private StreamHelper() {
@@ -53,8 +54,10 @@ private StreamHelper() {
     public static boolean saveXmlInStream(Document xmlContent,
                                           OutputStream outStream) {
         try {
+            // https://bz.apache.org/bugzilla/show_bug.cgi?id=67396
+            xmlContent.setXmlStandalone(true);
             Transformer trans = XMLHelper.newTransformer();
-            Source xmlSource = new DOMSource(xmlContent);
+            DOMSource xmlSource = new DOMSource(xmlContent);
             // prevent close of stream by transformer:
             Result outputTarget = new StreamResult(new FilterOutputStream(
                     outStream) {
@@ -69,7 +72,6 @@ public void close() throws IOException {
                     out.flush(); // only flush, don't close!
                 }
             });
-            // xmlContent.setXmlStandalone(true);
             trans.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
             // don't indent xml documents, the indent will cause errors in calculating the xml signature
             // because of different handling of linebreaks in Windows/Unix
diff --git a/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestStreamHelper.java b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestStreamHelper.java
new file mode 100644
index 00000000000..2b0effc6b44
--- /dev/null
+++ b/poi-ooxml/src/test/java/org/apache/poi/openxml4j/opc/TestStreamHelper.java
@@ -0,0 +1,38 @@
+package org.apache.poi.openxml4j.opc;
+
+import org.apache.commons.io.output.UnsynchronizedByteArrayOutputStream;
+import org.apache.poi.ooxml.util.DocumentHelper;
+import org.junit.jupiter.api.Test;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+import static org.apache.poi.xssf.usermodel.XSSFRelation.NS_WORDPROCESSINGML;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class TestStreamHelper {
+    @Test
+    void testStandaloneFlag() throws IOException {
+        Document doc = DocumentHelper.createDocument();
+        Element elDocument = doc.createElementNS(NS_WORDPROCESSINGML, "w:document");
+        doc.appendChild(elDocument);
+        Element elBody = doc.createElementNS(NS_WORDPROCESSINGML, "w:body");
+        elDocument.appendChild(elBody);
+        Element elParagraph = doc.createElementNS(NS_WORDPROCESSINGML, "w:p");
+        elBody.appendChild(elParagraph);
+        Element elRun = doc.createElementNS(NS_WORDPROCESSINGML, "w:r");
+        elParagraph.appendChild(elRun);
+        Element elText = doc.createElementNS(NS_WORDPROCESSINGML, "w:t");
+        elRun.appendChild(elText);
+        elText.setTextContent("Hello Open XML !");
+
+        try (UnsynchronizedByteArrayOutputStream bos = new UnsynchronizedByteArrayOutputStream()) {
+            StreamHelper.saveXmlInStream(doc, bos);
+            String xml = bos.toString(StandardCharsets.UTF_8);
+            assertTrue(xml.contains("standalone=\"yes\""), "xml contains standalone=yes?");
+            assertTrue(xml.contains("encoding=\"UTF-8\""), "xml contains encoding=UTF-8?");
+        }
+    }
+}