aaP_andrew
The password-changing functionality in Roundcube is provided by the "password" plugin. You can enable the plugin by adding it to the "plugins" array of your config/config.inc.php, like this:
$config['plugins'] = array('xskin', 'password');
When the plugin is enabled, the users can change their email password by logging in to Roundcube and going to Settings / Password.
