diff --git a/en_US/upgrade/0-upgrade.debian.8-9.md b/en_US/upgrade/0-upgrade.debian.8-9.md
index 6149392b..ec2cc1a9 100644
--- a/en_US/upgrade/0-upgrade.debian.8-9.md
+++ b/en_US/upgrade/0-upgrade.debian.8-9.md
@@ -2,6 +2,26 @@
 
 [TOC]
 
+## Postfix
+
+Run commands:
+
+```
+# Backup files
+cp /etc/postfix/main.cf /etc/postfix/main.cf.bak
+cp /etc/postfix/master.cf /etc/postfix/master.cf
+
+# Update main.cf and master.cf
+postconf -e daemon_directory='/usr/lib/postfix/sbin'
+postconf -e shlib_directory='/usr/lib/postfix'
+postconf -e compatibility_level=2
+for i in $(postconf -Mf | grep '^[0-9a-zA-Z]' | awk '{print $1"/"$2"/chroot=n"}'); do postconf -F $i; done
+```
+
+* Incorrect `daemon_directory` causes Postfix cannot start.
+* Incorrect `shlib_directory` causes Postfix cannot find pcre/mysql/pgsql/ldap modules.
+* Debian 8 ships Postfix 2.x, but Debian 9 ships Postfix 3.x, we need to disable compatible mode.
+
 ## Dovecot
 
 Please remove `!SSLv2` from parameter `ssl_protocols`, and restart Dovecot service:
@@ -9,3 +29,18 @@ Please remove `!SSLv2` from parameter `ssl_protocols`, and restart Dovecot servi
 ```
 ssl_protocols = !SSLv3
 ```
+
+## Fail2ban
+
+There's a duplicate parameter in file `/etc/fail2ban/jail.conf`, under section
+`[pam-generic]` like below:
+
+```
+[pam-generic]
+...
+port = all
+...
+port = anyport
+```
+
+Comment out `port = anyport` and restart fail2ban service.
diff --git a/html/upgrade.debian.8-9.html b/html/upgrade.debian.8-9.html
index a858a40c..8f90aa8e 100644
--- a/html/upgrade.debian.8-9.html
+++ b/html/upgrade.debian.8-9.html
@@ -19,15 +19,47 @@
 <div class="toc">
 <ul>
 <li><a href="#fixes-you-need-after-upgrading-debian-from-8-to-9">Fixes you need after upgrading Debian from 8 to 9</a><ul>
+<li><a href="#postfix">Postfix</a></li>
 <li><a href="#dovecot">Dovecot</a></li>
+<li><a href="#fail2ban">Fail2ban</a></li>
 </ul>
 </li>
 </ul>
 </div>
+<h2 id="postfix">Postfix</h2>
+<p>Run commands:</p>
+<pre><code># Backup files
+cp /etc/postfix/main.cf /etc/postfix/main.cf.bak
+cp /etc/postfix/master.cf /etc/postfix/master.cf
+
+# Update main.cf and master.cf
+postconf -e daemon_directory='/usr/lib/postfix/sbin'
+postconf -e shlib_directory='/usr/lib/postfix'
+postconf -e compatibility_level=2
+for i in $(postconf -Mf | grep '^[0-9a-zA-Z]' | awk '{print $1&quot;/&quot;$2&quot;/chroot=n&quot;}'); do postconf -F $i; done
+</code></pre>
+
+<ul>
+<li>Incorrect <code>daemon_directory</code> causes Postfix cannot start.</li>
+<li>Incorrect <code>shlib_directory</code> causes Postfix cannot find pcre/mysql/pgsql/ldap modules.</li>
+<li>Debian 8 ships Postfix 2.x, but Debian 9 ships Postfix 3.x, we need to disable compatible mode.</li>
+</ul>
 <h2 id="dovecot">Dovecot</h2>
 <p>Please remove <code>!SSLv2</code> from parameter <code>ssl_protocols</code>, and restart Dovecot service:</p>
 <pre><code>ssl_protocols = !SSLv3
-</code></pre><div class="footer">
+</code></pre>
+
+<h2 id="fail2ban">Fail2ban</h2>
+<p>There's a duplicate parameter in file <code>/etc/fail2ban/jail.conf</code>, under section
+<code>[pam-generic]</code> like below:</p>
+<pre><code>[pam-generic]
+...
+port = all
+...
+port = anyport
+</code></pre>
+
+<p>Comment out <code>port = anyport</code> and restart fail2ban service.</p><div class="footer">
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