diff --git a/docs/requirements.txt b/docs/requirements.txt
index dc4d303..54b76b7 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -3,6 +3,7 @@
 #
 # SPDX-License-Identifier: MIT
 
-sphinx>=4.0.0
+sphinx
 sphinxcontrib-jquery
+sphinx-rtd-theme
 pillow>=6.0.0