diff --git a/pyproject.toml b/pyproject.toml
index 76f30ce..639dac9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,7 +23,7 @@ dynamic = ["version"]
 [project.optional-dependencies]
 docs = [
     "Sphinx>=7.2.6,<8.0",
-    "sphinx-rtd-theme>=2.0.0,<3.0"
+    "sphinx-rtd-theme>=2.0.0,<4.0"
 ]
 tests = [
     "hypothesis>=6.99.12,<7.0",