diff --git a/docs/requirements.txt b/docs/requirements.txt
index 0ac25853..e535f8b2 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,4 +1,4 @@
 # MkDocs stack for CI and local builds (see root mkdocs.yml, docs_dir: docs).
 mkdocs-material>=9.5,<10
 mkdocs-mermaid2-plugin>=1.1.0
-pymdown-extensions>=10.7
+pymdown-extensions>=10.21.2