diff --git a/pyproject.toml b/pyproject.toml
index 2d6319dc..8c44273d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -57,7 +57,7 @@ sphinxcontrib-htmlhelp = "^2.1.0"
 sphinxcontrib-jsmath = "^1.0.1"
 sphinxcontrib-qthelp = "^1.0.8"
 sphinxcontrib-serializinghtml = "^1.1.10"
-sphinx-rtd-theme = ">=1.1.1,<3.0.0"
+sphinx-rtd-theme = ">=1.1.1,<4.0.0"
 sphinx-autodoc-typehints = ">=1.19.5,<3.0.0"
 autodocsumm = "^0.2.12"
 responses = ">=0.22,<0.26"