diff --git a/docs/content/config/troubleshooting/faq.md b/docs/content/config/troubleshooting/faq.md
index 720b2108..83476562 100644
--- a/docs/content/config/troubleshooting/faq.md
+++ b/docs/content/config/troubleshooting/faq.md
@@ -31,6 +31,10 @@ Assuming that you use `docker-compose` and a data volume container named `mailda
     -ti tvial/docker-mailserver \
     tar cvzf /backups/docker-mailserver-`date +%y%m%d-%H%M%S`.tgz /var/mail
 
+### What about `mail-state` folder?
+This folder consolidates all data generated by the server itself to persist when you upgrade.
+Example of data folder persisted: lib-amavis, lib-clamav, lib-fail2ban, lib-postfix, lib-postgrey, lib-spamassasin, lib-spamassassin, spool-postfix, ...
+
 ### How can I configure my email client?
 Login are full email address (`user@domain.com`).