diff --git a/docs/environment.yml b/docs/environment.yml
index 9c6999e48..8ff11251f 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -11,5 +11,5 @@ dependencies:
 - tornado
 - entrypoints
 - pip:
-    - sphinx>=1.5.1
+    - sphinx>=1.4.9
     - nbsphinx