diff --git a/requirements/docs.txt b/requirements/docs.txt
index 89fbf86c0..866c4d323 100644
--- a/requirements/docs.txt
+++ b/requirements/docs.txt
@@ -1,4 +1,4 @@
 recommonmark
-sphinx
+sphinx==4.0.2
 sphinx_markdown_tables
-sphinx_rtd_theme
+sphinx_rtd_theme==0.5.2