--- a/doc/bms.sgml	Wed Jan 15 15:30:27 2020 +0100
+++ b/doc/bms.sgml	Thu Jan 16 16:45:18 2020 +0100
@@ -1,4 +1,4 @@
-<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.4//EN" [
+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.5//EN" [
 <!ENTITY chapter1 SYSTEM "bms-ch1.sgml">
 <!ENTITY chapter2 SYSTEM "bms-ch2.sgml">
 <!ENTITY chapter3 SYSTEM "bms-ch3.sgml">
@@ -20,7 +20,7 @@
     </authorgroup>
 
     <copyright>
-	<year>2018</year>
+	<year>2018-2020</year>
 	<holder role='mailto:mbse@mbse.eu'>M. Broek</holder>
     </copyright>