diff --git a/terria/build/TerriaJS/doc/guide/requirements.txt b/terria/build/TerriaJS/doc/guide/requirements.txt
index 4f4b140..b28d338 100644
--- a/terria/build/TerriaJS/doc/guide/requirements.txt
+++ b/terria/build/TerriaJS/doc/guide/requirements.txt
@@ -6,7 +6,7 @@ MarkupSafe==1.0
 mkdocs==0.17.2
 mkdocs-material==2.7.0
 Pygments==2.2.0
-pymdown-extensions==4.9
+pymdown-extensions==10.0
 PyYAML==5.1
 six==1.11.0
 tornado==4.5.3