diff --git a/project.properties b/project.properties
index 04e87958..2ffa5706 100644
--- a/project.properties
+++ b/project.properties
@@ -39,6 +39,7 @@ maven.multiproject.excludes=plugin-parent/project.xml,examples/project.xml
 
 maven.xdoc.date = left
 maven.xdoc.date.format = dd MMMM yyyy HH:mm z
+maven.xdoc.version =
 
 maven.changelog.factory=org.apache.maven.svnlib.SvnChangeLogFactory
 maven.site.stage.address=www.apache.org