diff --git a/scour/scour.py b/scour/scour.py
index 0112ad1..1f14181 100644
--- a/scour/scour.py
+++ b/scour/scour.py
@@ -3090,7 +3090,10 @@ def scourString(in_string, options=None):
 
    # return the string with its XML prolog and surrounding comments
    if options.strip_xml_prolog == False:
-      total_output = '<?xml version="1.0" encoding="UTF-8" standalone="no"?>\n'
+      total_output = '<?xml version="1.0" encoding="UTF-8"'
+      if doc.standalone:
+         total_output += ' standalone="yes"'
+      total_output += '?>\n'
    else:
       total_output = ""
 
diff --git a/testscour.py b/testscour.py
index af9ce96..ee2eef7 100755
--- a/testscour.py
+++ b/testscour.py
@@ -1031,7 +1031,7 @@ class DoNotPrettyPrintWhenWhitespacePreserved(unittest.TestCase):
 	def runTest(self):
 		with open('unittests/whitespace-important.svg') as f:
 			s = scour.scourString(f.read()).splitlines()
-		c = '''<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+		c = '''<?xml version="1.0" encoding="UTF-8"?>
 <svg xmlns="http://www.w3.org/2000/svg">
  <text xml:space="preserve">This is some <tspan font-style="italic">messed-up</tspan> markup</text>
 </svg>
@@ -1044,7 +1044,7 @@ class DoNotPrettyPrintWhenNestedWhitespacePreserved(unittest.TestCase):
 	def runTest(self):
 		with open('unittests/whitespace-nested.svg') as f:
 			s = scour.scourString(f.read()).splitlines()
-		c = '''<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+		c = '''<?xml version="1.0" encoding="UTF-8"?>
 <svg xmlns="http://www.w3.org/2000/svg">
  <text xml:space="preserve"><tspan font-style="italic">Use <tspan font-style="bold">bold</tspan> text</tspan></text>
 </svg>