Mention Upgrade Dovecot from 2.2 to 2.3 for FreeBSD in iRedMail upgrade tutorial.

en_US/upgrade/0-upgrade.dovecot.2.2-2.3.md

@@ -28,6 +28,10 @@ cd /etc/dovecot/
 ```
 
 * On FreeBSD:
+    * Please upgrade ports `mail/dovecot` and `mail/dovecot-pigeonhole` first.
+      You can use tool like `portmaster` or `portupgrade` for this purpose.
+      FYI: [Using the Ports Collection](https://www.freebsd.org/doc/handbook/ports-using.html)
+    * After upgraded both ports, please run:
 
 ```
 cd /usr/local/etc/dovecot/

en_US/upgrade/0-upgrade.iredmail.0.9.7-0.9.8.md

@@ -83,6 +83,20 @@ you want to try v4, please follow our tutorial below to upgrade it.
 
 * [Upgrade SOGo from v3 to v4](./upgrade.sogo.3.to.4.html)
 
+### Upgrade Dovecot from 2.2 to 2.3
+
+!!! attention
+
+    This is only applicable to FreeBSD.
+
+Currently only FreeBSD offers Dovecot 2.3 by the ports tree, other Linux/BSD
+distributions still offers Dovecot 2.2, you should stick to Dovecot 2.2 if your
+Linux/BSD vendor doesn't offer 2.3 yet.
+
+Please follow our tutorial below to upgrade Dovecot:
+
+* [Upgrade Dovecot from 2.2.x to 2.3.x](./upgrade.dovecot.2.2-2.3.html)
+
 ### Fixed: SOGo backup script contains 3 issues
 
 SOGo backup script `/var/vmail/backup/backup_sogo.sh` shipped in iRedMail-0.9.7

html/upgrade.dovecot.2.2-2.3.html

@@ -40,7 +40,13 @@ convert your Dovecot 2.2 config file to fully work with Dovecot 2.3.</p>
 </code></pre>
 
 <ul>
-<li>On FreeBSD:</li>
+<li>On FreeBSD:<ul>
+<li>Please upgrade ports <code>mail/dovecot</code> and <code>mail/dovecot-pigeonhole</code> first.
+  You can use tool like <code>portmaster</code> or <code>portupgrade</code> for this purpose.
+  FYI: <a href="https://www.freebsd.org/doc/handbook/ports-using.html">Using the Ports Collection</a></li>
+<li>After upgraded both ports, please run:</li>
+</ul>
+</li>
 </ul>
 <pre><code>cd /usr/local/etc/dovecot/
 </code></pre>

html/upgrade.iredmail.0.9.7-0.9.8.html

@@ -26,6 +26,7 @@
 <li><a href="#upgrade-iredadmin-open-source-edition-to-the-latest-stable-release-09">Upgrade iRedAdmin (open source edition) to the latest stable release (0.9)</a></li>
 <li><a href="#upgrade-roundcube-webmail-to-the-latest-stable-release-135">Upgrade Roundcube webmail to the latest stable release (1.3.5)</a></li>
 <li><a href="#upgrade-sogo-from-v3-to-v4">Upgrade SOGo from v3 to v4</a></li>
+<li><a href="#upgrade-dovecot-from-22-to-23">Upgrade Dovecot from 2.2 to 2.3</a></li>
 <li><a href="#fixed-sogo-backup-script-contains-3-issues">Fixed: SOGo backup script contains 3 issues</a></li>
 <li><a href="#fail2ban-new-jail-postfix-pregreet">Fail2ban: new jail postfix-pregreet</a></li>
 <li><a href="#fixed-nginx-snippet-file-hard-codes-static-file-types-for-iredadmin">Fixed: Nginx snippet file hard-codes static file types for iRedAdmin</a></li>
@@ -133,6 +134,18 @@ you want to try v4, please follow our tutorial below to upgrade it.</p>
 <ul>
 <li><a href="./upgrade.sogo.3.to.4.html">Upgrade SOGo from v3 to v4</a></li>
 </ul>
+<h3 id="upgrade-dovecot-from-22-to-23">Upgrade Dovecot from 2.2 to 2.3</h3>
+<div class="admonition attention">
+<p class="admonition-title">Attention</p>
+<p>This is only applicable to FreeBSD.</p>
+</div>
+<p>Currently only FreeBSD offers Dovecot 2.3 by the ports tree, other Linux/BSD
+distributions still offers Dovecot 2.2, you should stick to Dovecot 2.2 if your
+Linux/BSD vendor doesn't offer 2.3 yet.</p>
+<p>Please follow our tutorial below to upgrade Dovecot:</p>
+<ul>
+<li><a href="./upgrade.dovecot.2.2-2.3.html">Upgrade Dovecot from 2.2.x to 2.3.x</a></li>
+</ul>
 <h3 id="fixed-sogo-backup-script-contains-3-issues">Fixed: SOGo backup script contains 3 issues</h3>
 <p>SOGo backup script <code>/var/vmail/backup/backup_sogo.sh</code> shipped in iRedMail-0.9.7
 and earlier releases contains 3 issues:</p>