diff --git a/docs/reference/api/ModemManager-docs.xml b/docs/reference/api/ModemManager-docs.xml
index bbcab97a..6fae038d 100644
--- a/docs/reference/api/ModemManager-docs.xml
+++ b/docs/reference/api/ModemManager-docs.xml
@@ -146,4 +146,8 @@
     <title>Index of new symbols in 1.16</title>
     <xi:include href="xml/api-index-1.16.xml"></xi:include>
   </chapter>
+  <chapter id="api-index-1-18" role="1.18">
+    <title>Index of new symbols in 1.18</title>
+    <xi:include href="xml/api-index-1.18.xml"></xi:include>
+  </chapter>
 </book>