diff --git a/en_US/faq/backup.restore.md b/en_US/faq/backup.restore.md
index 4acefc4c..23dac5f3 100644
--- a/en_US/faq/backup.restore.md
+++ b/en_US/faq/backup.restore.md
@@ -60,6 +60,8 @@ Notes:
document to generate DKIM key and update DNS record:
[Sign DKIM signature on outgoing emails for new mail domain](./sign.dkim.signature.for.new.domain.html).
+* SOGo (Calendar, Contacts, Tasks): check SOGo official document:
+
SOGo (Calendar, Contacts, Tasks): check SOGo official document: + http://wiki.sogo.nu/backupRestore
+OpenLDAP backend: