diff --git a/en_US/upgrade/0-upgrade.iredmail.0.9.3-0.9.4.md b/en_US/upgrade/0-upgrade.iredmail.0.9.3-0.9.4.md
index 27a85093..b9e02602 100644
--- a/en_US/upgrade/0-upgrade.iredmail.0.9.3-0.9.4.md
+++ b/en_US/upgrade/0-upgrade.iredmail.0.9.3-0.9.4.md
@@ -41,3 +41,16 @@ Please follow Roundcube official tutorial to upgrade Roundcube webmail to the
 latest stable release immediately: [How to upgrade Roundcube](http://trac.roundcube.net/wiki/Howto_Upgrade)
 
 Note: package `rsync` must be installed on your server before upgrading.
+
+
+### FreeBSD: Fix incorrect file permission of /etc/mail/mailer.conf
+
+> This is applicable to only FreeBSD.
+
+iRedMail generates /etc/mail/mailer.conf with permission 0600 during
+installation, but it should be world-readable. Please fix this issue with
+command below:
+
+```
+chmod +r /etc/mail/mailer.conf
+```
diff --git a/html/upgrade.iredmail.0.9.3-0.9.4.html b/html/upgrade.iredmail.0.9.3-0.9.4.html
index debfc1b0..0a7be517 100644
--- a/html/upgrade.iredmail.0.9.3-0.9.4.html
+++ b/html/upgrade.iredmail.0.9.3-0.9.4.html
@@ -20,6 +20,7 @@
 <li><a href="#upgrade-iredapd-postfix-policy-server-to-the-latest-171">Upgrade iRedAPD (Postfix policy server) to the latest 1.7.1</a></li>
 <li><a href="#upgrade-iredadmin-open-source-edition-to-the-latest-stable-release">Upgrade iRedAdmin (open source edition) to the latest stable release</a></li>
 <li><a href="#upgrade-roundcube-webmail-to-the-latest-stable-release">Upgrade Roundcube webmail to the latest stable release</a></li>
+<li><a href="#freebsd-fix-incorrect-file-permission-of-etcmailmailerconf">FreeBSD: Fix incorrect file permission of /etc/mail/mailer.conf</a></li>
 </ul>
 </li>
 </ul>
@@ -52,7 +53,16 @@ latest stable release:
 <h3 id="upgrade-roundcube-webmail-to-the-latest-stable-release">Upgrade Roundcube webmail to the latest stable release</h3>
 <p>Please follow Roundcube official tutorial to upgrade Roundcube webmail to the
 latest stable release immediately: <a href="http://trac.roundcube.net/wiki/Howto_Upgrade">How to upgrade Roundcube</a></p>
-<p>Note: package <code>rsync</code> must be installed on your server before upgrading.</p><p style="text-align: center; color: grey;">All documents are available in <a href="https://bitbucket.org/zhb/iredmail-docs/src">BitBucket repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. If you found something wrong, please do <a href="http://www.iredmail.org/contact.html">contact us</a> to fix it.<script>
+<p>Note: package <code>rsync</code> must be installed on your server before upgrading.</p>
+<h3 id="freebsd-fix-incorrect-file-permission-of-etcmailmailerconf">FreeBSD: Fix incorrect file permission of /etc/mail/mailer.conf</h3>
+<blockquote>
+<p>This is applicable to only FreeBSD.</p>
+</blockquote>
+<p>iRedMail generates /etc/mail/mailer.conf with permission 0600 during
+installation, but it should be world-readable. Please fix this issue with
+command below:</p>
+<pre><code>chmod +r /etc/mail/mailer.conf
+</code></pre><p style="text-align: center; color: grey;">All documents are available in <a href="https://bitbucket.org/zhb/iredmail-docs/src">BitBucket repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. If you found something wrong, please do <a href="http://www.iredmail.org/contact.html">contact us</a> to fix it.<script>
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