diff --git a/tools/validate.py b/tools/validate.py
index 9ac9feb74d..583b2bc9fa 100755
--- a/tools/validate.py
+++ b/tools/validate.py
@@ -28,7 +28,7 @@ EXCEPTIONS = ['ha-guide-docinfo.xml']
 
 def get_schema():
     """Return the DocBook RELAX NG schema"""
-    url = "http://www.docbook.org/xml/5.0/rng/docbookxi.rng"
+    url = "http://www.oasis-open.org/docbook/xml/5.0b5/rng/docbookxi.rng"
     relaxng_doc = etree.parse(urllib2.urlopen(url))
     return etree.RelaxNG(relaxng_doc)