diff --git a/manifest.json b/manifest.json
index 08bc541..75e537f 100644
--- a/manifest.json
+++ b/manifest.json
@@ -314,6 +314,7 @@
 		"18-15",
 		"18-17",
 		"18-19",
+		"18-21",
 		"18-27",
 		"18-30",
 		"19-title",