diff --git a/doc/conf.py b/doc/conf.py
index 84ea8de0f2deeaaab2e975d8788083d6842b85c6..b630823e5fab201dfc25c50490b7e988c1fe7151 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -25,7 +25,7 @@ extensions = [
 templates_path = ['_templates']
 source_suffix = '.rst'
 source_encoding = 'utf-8-sig'
-master_doc = 'index'
+root_doc = 'index'
 
 # extlinks -- see http://www.sphinx-doc.org/en/stable/ext/extlinks.html
 extlinks = {