diff --git a/docs/requirements.txt b/docs/requirements.txt
index f58d1c77..24931796 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,3 +1,3 @@
 m2r2>=0.3.2
 sphinx>=7.2.6,<9
-sphinx-rtd-theme>=2.0.0,<3
+sphinx-rtd-theme>=2.0.0,<4