diff --git a/pyproject.toml b/pyproject.toml
index c55ab29c..db264822 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -69,7 +69,7 @@ optional-dependencies.dev = [
     "sphinx-copybutton==0.5.2",
     "sphinx-lint==1.0.2",
     "sphinx-pyproject==0.3.0",
-    "sphinx-substitution-extensions==2025.11.17",
+    "sphinx-substitution-extensions==2025.12.15",
     "sphinxcontrib-spelling==8.0.2",
     "sybil==9.3.0",
     "ty==0.0.1a34",