diff --git a/pyproject.toml b/pyproject.toml
index 9478880..b9d669d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -65,7 +65,7 @@ docs = [
     "mkdocs-minify-plugin~=0.8",
     "mkdocs-nav-weight~=0.3",
     "mkdocs-section-index~=0.3",
-    "pymdown-extensions~=10.21",
+    "pymdown-extensions>=10.21,<12.0",
 ]
 
 [project.scripts]