diff --git a/admin-guide/configuration/monitoring/icinga2.md b/admin-guide/configuration/monitoring/icinga2.md
index 63ebd931..1569511c 100644
--- a/admin-guide/configuration/monitoring/icinga2.md
+++ b/admin-guide/configuration/monitoring/icinga2.md
@@ -88,6 +88,7 @@ icinga2::alerting::notify_admins: false
 Additionally to/instead of the admins you can list the notification recipients in the Hiera list `icinga2::alerting::contacts`. You can list
 - AD users by login name
 - AD groups with `%` as prefix to their name
+- plain e-mail addresses
 
 ### Notificiation Time Restrictions