diff --git a/templates/application/config.php.erb b/templates/application/config.php.erb
index f804137..c48eceb 100644
--- a/templates/application/config.php.erb
+++ b/templates/application/config.php.erb
@@ -57,6 +57,7 @@ $CONFIG = array (
   'gss.master.url' => '<%= @gss_master_url %>',
   'gss.mode' => '<%= @gss_mode %>',
   'gss.user.discovery.module' => '\\OCA\\GlobalSiteSelector\\UserDiscoveryModules\\ManualUserMapping',
+  'gss.username_format' => 'sanitize',
   'installed' => true,
   'instanceid' => '<%= @instanceid %>',
   'integrity.check.disabled' => true,