diff --git a/doc/en/index.docbook b/doc/en/index.docbook
index 0b18609..d5090cc 100644
--- a/doc/en/index.docbook
+++ b/doc/en/index.docbook
@@ -1,5 +1,5 @@
 <?xml version="1.0" ?>
-<!DOCTYPE book PUBLIC "-//KDE//DTD DocBook XML V4.1-Based Variant V1.0//EN" "dtd/kdex.dtd" [
+<!DOCTYPE book PUBLIC "-//KDE//DTD DocBook XML V4.2-Based Variant V1.1//EN" "dtd/kdex.dtd" [
   <!ENTITY knowit '<application>KnowIt</application>'>
   <!ENTITY kapp "&knowit;"><!-- replace knowit here -->
   <!ENTITY % addindex "IGNORE">