diff --git a/doc/manpages/dispersion.conf.5 b/doc/manpages/dispersion.conf.5
index dd2f44c2ae..ec6029a62e 100644
--- a/doc/manpages/dispersion.conf.5
+++ b/doc/manpages/dispersion.conf.5
@@ -36,6 +36,8 @@ Any line that begins with a '#' symbol is ignored.
 .SH PARAMETERS
 .PD 1 
 .RS 0
+.IP "\fBauth_version\fR"
+Authentication system API version. The default is 1.0.
 .IP "\fBauth_url\fR"
 Authentication system URL 
 .IP "\fBauth_user\fR"