diff --git a/Makefile b/Makefile
index bc7f4c3..00e6578 100644
--- a/Makefile
+++ b/Makefile
@@ -71,6 +71,7 @@ pve-admin-guide.html: ${PVE_ADMIN_GUIDE_SOURCES}
 	test -z "$${NOVIEW}" && iceweasel $@ &
 
 pve-admin-guide.pdf: ${PVE_ADMIN_GUIDE_SOURCES} docinfo.xml pve-admin-guide-docinfo.xml
+	grep ">Release ${RELEASE}<" pve-admin-guide-docinfo.xml || (echo "wrong release in  pve-admin-guide-docinfo.xml" && false);
 	a2x -a docinfo -a docinfo1 -f pdf -L --dblatex-opts "-P latex.output.revhistory=0" pve-admin-guide.adoc
 	test -z "$${NOVIEW}" && iceweasel $@ &
 
diff --git a/pve-admin-guide-docinfo.xml b/pve-admin-guide-docinfo.xml
index 5267955..ad73960 100644
--- a/pve-admin-guide-docinfo.xml
+++ b/pve-admin-guide-docinfo.xml
@@ -1,3 +1,5 @@
+<subtitle>Release 4.1</subtitle>
+
 <copyright>
   <year>2016</year>
   <holder>Proxmox Server Solutions Gmbh</holder>