diff --git a/pyproject.toml b/pyproject.toml
index bf823f1..ba38d59 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,7 +22,7 @@ requires-python = ">=3.11"
 docs = [
     "mkdocs>=1.6.1,<2",
     "mkdocs-material>=9.7.7,<10",
-    "pymdown-extensions>=12.3,<13",
+    "pymdown-extensions>=12.3,<14",
 ]
 
 # Tests of `scripts/check_names.py`