diff --git a/en_US/upgrade/0-upgrade.iredmail.0.9.9-1.0.md b/en_US/upgrade/0-upgrade.iredmail.0.9.9-1.0.md
index 6b0c4c35..0d026296 100644
--- a/en_US/upgrade/0-upgrade.iredmail.0.9.9-1.0.md
+++ b/en_US/upgrade/0-upgrade.iredmail.0.9.9-1.0.md
@@ -32,9 +32,9 @@ so that you can know which version of iRedMail you're running. For example:
 
 !!! attention
 
-    iRedAPD offers SRS (Sender Rewriting Scheme) support in this release, by
+    iRedAPD offers SRS (Sender Rewriting Scheme) support in this release, but
     it's disabled by default, please read our tutorial to understand known
-    issues and how to enable it.
+    issues and how to enable it: [Enable SRS (Sender Rewriting Scheme) support](./srs.html).
 
 Please follow below tutorial to upgrade iRedAPD to the latest stable release:
 [Upgrade iRedAPD to the latest stable release](./upgrade.iredapd.html)
@@ -127,37 +127,6 @@ wget -O dovecot.iredmail.conf https://bitbucket.org/zhb/iredmail/raw/default/iRe
 
 Restarting Fail2ban service is required.
 
-### [OPTIONAL] Enable SRS (Sender Rewriting Scheme) support in Postfix
-
-After you have iRedAPD upgraded to version 2.5, it will listen on 2 new network
-ports: 7778 and 7779. They're used by Postfix for SRS (Sender Rewriting Scheme).
-For technical details of SRS, please read this paper:
-[The Sender Rewriting Scheme (PDF)](https://www.libsrs2.org/srs/srs.pdf).
-
-To enable SRS support, please add parameters below in Postfix config file
-`/etc/postfix/main.cf` (on Linux/OpenBSD) or `/usr/local/etc/postfix/main.cf`
-(on FreeBSD):
-
-```
-sender_canonical_maps = tcp:127.0.0.1:7778
-sender_canonical_classes = envelope_sender
-recipient_canonical_maps = tcp:127.0.0.1:7779
-recipient_canonical_classes= envelope_recipient,header_recipient
-```
-
-Reloading or restarting Postfix service is required.
-
-!!! note "Known Issues"
-
-    * Sender addresses will always be rewritten even if the mail is not
-      forwarded at all. This is because the canonical maps are read by the
-      Postfix cleanup daemon, which processes mails at the very beginning
-      before any routing decision is made.
-
-    * Postfix will use rewritten address in the `Return-Path:` header, if you
-      have any sieve rules based on `Return-Path:`, it MAY not work anymore and
-      please update your sieve rules to match rewritten address.
-
 ### [OPTIONAL] Enable mailbox quota status check in Dovecot and Postfix.
 
 With default iRedMail settings, Postfix accepts email without checking whether
diff --git a/html/upgrade.iredmail.0.9.9-1.0.html b/html/upgrade.iredmail.0.9.9-1.0.html
index 3488810c..5e7f8871 100644
--- a/html/upgrade.iredmail.0.9.9-1.0.html
+++ b/html/upgrade.iredmail.0.9.9-1.0.html
@@ -29,7 +29,6 @@
 <li><a href="#upgrade-netdata-to-the-latest-stable-release-1150">Upgrade netdata to the latest stable release (1.15.0)</a></li>
 <li><a href="#fixed-improper-order-of-postfix-smtpd_sender_restriction-rules">Fixed: improper order of Postfix smtpd_sender_restriction rules</a></li>
 <li><a href="#fail2ban-slightly-loose-filter-rule-for-postfix">Fail2ban: slightly loose filter rule for postfix</a></li>
-<li><a href="#optional-enable-srs-sender-rewriting-scheme-support-in-postfix">[OPTIONAL] Enable SRS (Sender Rewriting Scheme) support in Postfix</a></li>
 <li><a href="#optional-enable-mailbox-quota-status-check-in-dovecot-and-postfix">[OPTIONAL] Enable mailbox quota status check in Dovecot and Postfix.</a><ul>
 <li><a href="#enable-quota-status-service-in-dovecot">Enable quota-status service in Dovecot</a></li>
 <li><a href="#enable-quota-status-check-in-postfix">Enable quota status check in Postfix</a></li>
@@ -64,9 +63,9 @@ so that you can know which version of iRedMail you're running. For example:</p>
 <h3 id="upgrade-iredapd-postfix-policy-server-to-the-latest-stable-release">Upgrade iRedAPD (Postfix policy server) to the latest stable release</h3>
 <div class="admonition attention">
 <p class="admonition-title">Attention</p>
-<p>iRedAPD offers SRS (Sender Rewriting Scheme) support in this release, by
+<p>iRedAPD offers SRS (Sender Rewriting Scheme) support in this release, but
 it's disabled by default, please read our tutorial to understand known
-issues and how to enable it.</p>
+issues and how to enable it: <a href="./srs.html">Enable SRS (Sender Rewriting Scheme) support</a>.</p>
 </div>
 <p>Please follow below tutorial to upgrade iRedAPD to the latest stable release:
 <a href="./upgrade.iredapd.html">Upgrade iRedAPD to the latest stable release</a></p>
@@ -147,37 +146,6 @@ wget -O dovecot.iredmail.conf https://bitbucket.org/zhb/iredmail/raw/default/iRe
 </code></pre>
 
 <p>Restarting Fail2ban service is required.</p>
-<h3 id="optional-enable-srs-sender-rewriting-scheme-support-in-postfix">[OPTIONAL] Enable SRS (Sender Rewriting Scheme) support in Postfix</h3>
-<p>After you have iRedAPD upgraded to version 2.5, it will listen on 2 new network
-ports: 7778 and 7779. They're used by Postfix for SRS (Sender Rewriting Scheme).
-For technical details of SRS, please read this paper:
-<a href="https://www.libsrs2.org/srs/srs.pdf">The Sender Rewriting Scheme (PDF)</a>.</p>
-<p>To enable SRS support, please add parameters below in Postfix config file
-<code>/etc/postfix/main.cf</code> (on Linux/OpenBSD) or <code>/usr/local/etc/postfix/main.cf</code>
-(on FreeBSD):</p>
-<pre><code>sender_canonical_maps = tcp:127.0.0.1:7778
-sender_canonical_classes = envelope_sender
-recipient_canonical_maps = tcp:127.0.0.1:7779
-recipient_canonical_classes= envelope_recipient,header_recipient
-</code></pre>
-
-<p>Reloading or restarting Postfix service is required.</p>
-<div class="admonition note">
-<p class="admonition-title">Known Issues</p>
-<ul>
-<li>
-<p>Sender addresses will always be rewritten even if the mail is not
-  forwarded at all. This is because the canonical maps are read by the
-  Postfix cleanup daemon, which processes mails at the very beginning
-  before any routing decision is made.</p>
-</li>
-<li>
-<p>Postfix will use rewritten address in the <code>Return-Path:</code> header, if you
-  have any sieve rules based on <code>Return-Path:</code>, it MAY not work anymore and
-  please update your sieve rules to match rewritten address.</p>
-</li>
-</ul>
-</div>
 <h3 id="optional-enable-mailbox-quota-status-check-in-dovecot-and-postfix">[OPTIONAL] Enable mailbox quota status check in Dovecot and Postfix.</h3>
 <p>With default iRedMail settings, Postfix accepts email without checking whether
 user's mailbox is over quota, then pipes email to Dovecot LDA for local