Download Roundcube 1.3.x to the web htdocs directory and extract it (here `rc/`):
```
cd data/web
wget -O - https://github.com/roundcube/roundcubemail/releases/download/1.3.x/roundcubemail-1.3.x-complete.tar.gz | tar xfvz -
# Change folder name
mv roundcubemail-1.3.x rc
# Change permissions
chown -R root: rc/
```

Create a file `data/web/rc/config/config.inc.php` with the following content.

**Change the `des_key` parameter to a random value.** It is used to temporarily store your IMAP password.

```
<?php
error_reporting(0);
if (!file_exists('/tmp/mime.types')) {
file_put_contents("/tmp/mime.types", fopen("http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types", 'r'));
}
$config = array();
$config['db_dsnw'] = 'mysql://' . getenv('DBUSER') . ':' . getenv('DBPASS') . '@mysql/' . getenv('DBNAME');
$config['default_host'] = 'tls://dovecot';
$config['default_port'] = '143';
$config['smtp_server'] = 'tls://postfix';
$config['smtp_port'] = 587;
$config['smtp_user'] = '%u';
$config['smtp_pass'] = '%p';
$config['support_url'] = '';
$config['product_name'] = 'Roundcube Webmail';
$config['des_key'] = 'yourrandomstring_changeme';
$config['log_dir'] = '/dev/null';
$config['temp_dir'] = '/tmp';
$config['plugins'] = array(
  'archive',
  'managesieve'
);
$config['skin'] = 'larry';
$config['mime_types'] = '/tmp/mime.types';
$config['imap_conn_options'] = array(
  'ssl' => array('verify_peer' => false, 'verify_peer_name' => false, 'allow_self_signed' => true)
);
$config['enable_installer'] = true;
$config['smtp_conn_options'] = array(
  'ssl' => array('verify_peer' => false, 'verify_peer_name' => false, 'allow_self_signed' => true)
);

$config['managesieve_port'] = 4190;
$config['managesieve_host'] = 'tls://dovecot';
$config['managesieve_conn_options'] = array(
  'ssl' => array('verify_peer' => false, 'verify_peer_name' => false, 'allow_self_signed' => true)
);
// Enables separate management interface for vacation responses (out-of-office)
// 0 - no separate section (default),
// 1 - add Vacation section,
// 2 - add Vacation section, but hide Filters section
$config['managesieve_vacation'] = 1;

```

Point your browser to `https://myserver/rc/installer` and follow the instructions.
Initialize the database and leave the installer.

**Delete the directory `data/web/rc/installer` after a successful installation!**

### Enable change password function in Roundcube

Open `data/web/rc/config/config.inc.php` and enable the password plugin:

```
...
$config['plugins'] = array(
    'archive',
    'password',
);
...
```

Open `data/web/rc/plugins/password/password.php`, search for `case 'ssha':` and add above:

```
        case 'ssha256':
            $salt = rcube_utils::random_bytes(8);
            $crypted = base64_encode( hash('sha256', $password . $salt, TRUE ) . $salt );
            $prefix  = '{SSHA256}';
            break;
```

Open `data/web/rc/plugins/password/config.inc.php` and change the following parameters (or add them at the bottom of that file):

```
$config['password_driver'] = 'sql';
$config['password_algorithm'] = 'ssha256';
$config['password_algorithm_prefix'] = '{SSHA256}';
$config['password_query'] = "UPDATE mailbox SET password = %P WHERE username = %u";
```

---

Optionally, you can add Roundcube's link to the mailcow Apps list.
To do this, open or create `data/web/inc/vars.local.inc.php` and add the following code-block:

*NOTE: Don't forget to add the `<?php` delimiter on the first line*

````
...
$MAILCOW_APPS = array(
  array(
    'name' => 'SOGo',
    'link' => '/SOGo/'
  ),
  array(
    'name' => 'Roundcube',
    'link' => '/rc/'
   )
);
...
````