diff --git a/docs/_index.md b/docs/_index.md
index 3ba499cc34aae16ef22f753d907b21416c6afb83..e348829dc7cbb1d9d2c577187f595052dc3ed5d3 100644
--- a/docs/_index.md
+++ b/docs/_index.md
@@ -13,6 +13,7 @@ License: GNU GPL 3.0 <http://www.gnu.org/licenses/gpl-3.0.html>
 * openssl
 * curl
 * acme.sh client
+* dig (opional)
 
 ## Why?