diff --git a/docs/requirements.txt b/docs/requirements.txt
index 8fd28e4779..8dda0718cd 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,2 +1,3 @@
 six
-sphinx-markdown-tables
\ No newline at end of file
+sphinx==3.5.4
+sphinx-markdown-tables