diff --git a/docs/requirements.txt b/docs/requirements.txt
index ab6912395..6bedfb0dd 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,2 +1,2 @@
-Sphinx
-sphinx-book-theme
+Sphinx==3.5.3
+sphinx-book-theme==0.1.0