Determine opensearch URL from current version.
diff --git a/Doc/conf.py b/Doc/conf.py
index 6bbe4ce..6b085e0 100644
--- a/Doc/conf.py
+++ b/Doc/conf.py
@@ -91,7 +91,7 @@
 }
 
 # Output an OpenSearch description file.
-html_use_opensearch = 'http://docs.python.org/3.3'
+html_use_opensearch = 'http://docs.python.org/' + version
 
 # Additional static files.
 html_static_path = ['tools/sphinxext/static']