One more comment line.

fixes #6

en_US/installation/0-install.iredmail.on.debian.ubuntu.md

@@ -179,6 +179,11 @@ is full email address.
           ActiveSync. If you need calendar and contacts support, also syncing
           them to mobile or PC mail client applications, then SOGo is the one
           to go. Note: If you have many ActiveSync clients, it requires a lot RAM.
+        - It's ok to install both, but you can only manage mail filters with
+          Roundcube in this case, because the filter rules generated by
+          Roundcube and SOGo are not compatible. You can [force to enable it in
+          SOGo](./why.no.sieve.support.in.sogo.html), but please inform end
+          users and ask them to stick to one of them for managing mail filters.
 
 ![](./images/installation/optional_components.png){: width="700px" }
 

en_US/installation/0-install.iredmail.on.freebsd.md

@@ -172,6 +172,11 @@ is full email address.
           ActiveSync. If you need calendar and contacts support, also syncing
           them to mobile or PC mail client applications, then SOGo is the one
           to go. Note: If you have many ActiveSync clients, it requires a lot RAM.
+        - It's ok to install both, but you can only manage mail filters with
+          Roundcube in this case, because the filter rules generated by
+          Roundcube and SOGo are not compatible. You can [force to enable it in
+          SOGo](./why.no.sieve.support.in.sogo.html), but please inform end
+          users and ask them to stick to one of them for managing mail filters.
 
 ![](./images/installation/optional_components.png){: width="700px" }
 

en_US/installation/0-install.iredmail.on.freebsd.with.jail.md

@@ -199,6 +199,11 @@ is full email address.
           ActiveSync. If you need calendar and contacts support, also syncing
           them to mobile or PC mail client applications, then SOGo is the one
           to go. Note: If you have many ActiveSync clients, it requires a lot RAM.
+        - It's ok to install both, but you can only manage mail filters with
+          Roundcube in this case, because the filter rules generated by
+          Roundcube and SOGo are not compatible. You can [force to enable it in
+          SOGo](./why.no.sieve.support.in.sogo.html), but please inform end
+          users and ask them to stick to one of them for managing mail filters.
 
 ![](./images/installation/optional_components.png){: width="700px" }
 

en_US/installation/0-install.iredmail.on.openbsd.md

@@ -201,6 +201,11 @@ is full email address.
           ActiveSync. If you need calendar and contacts support, also syncing
           them to mobile or PC mail client applications, then SOGo is the one
           to go. Note: If you have many ActiveSync clients, it requires a lot RAM.
+        - It's ok to install both, but you can only manage mail filters with
+          Roundcube in this case, because the filter rules generated by
+          Roundcube and SOGo are not compatible. You can [force to enable it in
+          SOGo](./why.no.sieve.support.in.sogo.html), but please inform end
+          users and ask them to stick to one of them for managing mail filters.
 
 ![](./images/installation/optional_components.png){: width="700px" }
 

en_US/installation/0-install.iredmail.on.rhel.md

@@ -205,6 +205,11 @@ is full email address.
           ActiveSync. If you need calendar and contacts support, also syncing
           them to mobile or PC mail client applications, then SOGo is the one
           to go. Note: If you have many ActiveSync clients, it requires a lot RAM.
+        - It's ok to install both, but you can only manage mail filters with
+          Roundcube in this case, because the filter rules generated by
+          Roundcube and SOGo are not compatible. You can [force to enable it in
+          SOGo](./why.no.sieve.support.in.sogo.html), but please inform end
+          users and ask them to stick to one of them for managing mail filters.
 
 ![](./images/installation/optional_components.png){: width="700px" }
 

html/install.iredmail.on.debian.ubuntu.html

@@ -209,6 +209,11 @@ is full email address.</p>
   ActiveSync. If you need calendar and contacts support, also syncing
   them to mobile or PC mail client applications, then SOGo is the one
   to go. Note: If you have many ActiveSync clients, it requires a lot RAM.</li>
+<li>It's ok to install both, but you can only manage mail filters with
+  Roundcube in this case, because the filter rules generated by
+  Roundcube and SOGo are not compatible. You can <a href="./why.no.sieve.support.in.sogo.html">force to enable it in
+  SOGo</a>, but please inform end
+  users and ask them to stick to one of them for managing mail filters.</li>
 </ul>
 </div>
 </li>

html/install.iredmail.on.freebsd.html

@@ -197,6 +197,11 @@ is full email address.</p>
   ActiveSync. If you need calendar and contacts support, also syncing
   them to mobile or PC mail client applications, then SOGo is the one
   to go. Note: If you have many ActiveSync clients, it requires a lot RAM.</li>
+<li>It's ok to install both, but you can only manage mail filters with
+  Roundcube in this case, because the filter rules generated by
+  Roundcube and SOGo are not compatible. You can <a href="./why.no.sieve.support.in.sogo.html">force to enable it in
+  SOGo</a>, but please inform end
+  users and ask them to stick to one of them for managing mail filters.</li>
 </ul>
 </div>
 </li>

html/install.iredmail.on.freebsd.with.jail.html

@@ -236,6 +236,11 @@ is full email address.</p>
   ActiveSync. If you need calendar and contacts support, also syncing
   them to mobile or PC mail client applications, then SOGo is the one
   to go. Note: If you have many ActiveSync clients, it requires a lot RAM.</li>
+<li>It's ok to install both, but you can only manage mail filters with
+  Roundcube in this case, because the filter rules generated by
+  Roundcube and SOGo are not compatible. You can <a href="./why.no.sieve.support.in.sogo.html">force to enable it in
+  SOGo</a>, but please inform end
+  users and ask them to stick to one of them for managing mail filters.</li>
 </ul>
 </div>
 </li>

html/install.iredmail.on.openbsd.html

@@ -229,6 +229,11 @@ is full email address.</p>
   ActiveSync. If you need calendar and contacts support, also syncing
   them to mobile or PC mail client applications, then SOGo is the one
   to go. Note: If you have many ActiveSync clients, it requires a lot RAM.</li>
+<li>It's ok to install both, but you can only manage mail filters with
+  Roundcube in this case, because the filter rules generated by
+  Roundcube and SOGo are not compatible. You can <a href="./why.no.sieve.support.in.sogo.html">force to enable it in
+  SOGo</a>, but please inform end
+  users and ask them to stick to one of them for managing mail filters.</li>
 </ul>
 </div>
 </li>

html/install.iredmail.on.rhel.html

@@ -235,6 +235,11 @@ is full email address.</p>
   ActiveSync. If you need calendar and contacts support, also syncing
   them to mobile or PC mail client applications, then SOGo is the one
   to go. Note: If you have many ActiveSync clients, it requires a lot RAM.</li>
+<li>It's ok to install both, but you can only manage mail filters with
+  Roundcube in this case, because the filter rules generated by
+  Roundcube and SOGo are not compatible. You can <a href="./why.no.sieve.support.in.sogo.html">force to enable it in
+  SOGo</a>, but please inform end
+  users and ask them to stick to one of them for managing mail filters.</li>
 </ul>
 </div>
 </li>