doc/administration/reply_by_email.md
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GitLab can be set up to allow users to comment on issues and merge requests by replying to notification emails.
Make sure incoming email is set up.
Replying by email happens in three steps:
When GitLab sends a notification email:
Reply-To header is set to your configured email address.%{key} placeholder, it's replaced with a specific reply key.References header.When you reply to the notification email, your email client:
Reply-To address it got from the notification email.In-Reply-To header to the value of the Message-ID header from the
notification email.References header to the value of the Message-ID plus the value of
the notification email's References header.When GitLab receives your reply, it looks for the reply key in the list of accepted headers.
If a reply key is found, your response appears as a comment on the relevant issue, merge request, commit, or other item that triggered the notification.
For more information about the Message-ID, In-Reply-To, and References headers,
see RFC 5322.
Some incoming email features require GitLab to store metadata about sent email notifications. We retain these records for two years. If an email notification is older than two years, you cannot reply by email to that notification. This includes replying by email to issue and merge request threads.