diff --git a/pyproject.toml b/pyproject.toml
index e326e22..5488515 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,7 +50,7 @@ Download = "https://pypi.org/project/callosum"
 
 [project.optional-dependencies]
 docs = [
-    "sphinx~=4.3",
+    "sphinx>=4.3,<10.0",
     "sphinx-autodoc-typehints",
 ]
 thrift = [