diff --git a/docs/readthedocs/source/doc/Nano/Overview/hpo.rst b/docs/readthedocs/source/doc/Nano/Overview/hpo.rst
index c48135d9..3b0a0f69 100644
--- a/docs/readthedocs/source/doc/Nano/Overview/hpo.rst
+++ b/docs/readthedocs/source/doc/Nano/Overview/hpo.rst
@@ -18,7 +18,7 @@ Next, install a few dependencies required for Nano HPO using below commands.
 .. code-block:: console
 
     pip install ConfigSpace
-    pip install optuna
+    pip install optuna<=3.1.1