diff --git a/docs/requirements.txt b/docs/requirements.txt
index 6759bd07..28da095d 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,2 +1,2 @@
 sphinx >= 4.0, < 9.0
-sphinx_rtd_theme < 3.0
+sphinx_rtd_theme < 4.0