Online Status Timeout is just time, in which set cookie with session_id.
This time in code, XenForo_Session (\library\XenForo\Session.php)
Find this code:
Code:
public function __construct(array $config = array(), Zend_Cache_Core $cache = null, Zend_Db_Adapter_Abstract $db = null)
{
if (empty($config['admin']))
{
$defaultConfig = array(
'table' => 'xf_session',
'cacheName' => 'session',
'cookie' => 'session',
'lifetime' => 3600
);
}
else
{
$defaultConfig = array(
'table' => 'xf_session_admin',
'cacheName' => 'session_admin',
'cookie' => 'session_admin',
'lifetime' => (XenForo_Application::debugMode() ? 86400 : 3600) // longer lifetime in debug mode to get in the way less
);
unset($config['admin']);
}
'lifetime' => 3600 - it is what You need. Just change 3600 to You time.
As for addon for this, I dont know how to extends this class so can not make addon.