diff --git a/docs/requirements.txt b/docs/requirements.txt
index f52320d..8f15ab0 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,7 +1,7 @@
 ipython
 pygments >= 2.7.*
 pydata-sphinx-theme
-sphinx
+sphinx >= 6.*
 pandas
 lxml
 numpy