diff --git a/header.adoc b/header.adoc
index 8c735d2c..b0d49b2a 100644
--- a/header.adoc
+++ b/header.adoc
@@ -22,8 +22,9 @@
 :lang: en
 :listing-caption: Listing
 :sectnums:
+:sectnumlevels: 5
 :toc: left
-:toclevels: 4
+:toclevels: 5
 :source-highlighter: pygments
 ifdef::backend-pdf[]
 :source-highlighter: coderay