diff --git a/source/conf.py b/source/conf.py
index b071c9591..8d77f1a51 100644
--- a/source/conf.py
+++ b/source/conf.py
@@ -156,7 +156,7 @@
     'current_version': release,
     'versions' : [
         ['latest', '/latest/'],
-        ['4.0', '/release-4.0'],
+        ['4.0', '/release-4.0/'],
         ['3.0', '/release-3.0/'],
         ['2.0', '/release-2.0/'],
         ['1.8', '/release-1.8/'],