Ip\Application::getVersion PHP Method

    public static function getVersion()
    {
        return '4.9.0';
        //CHANGE_ON_VERSION_UPDATE
    }

 public function activate()
 {
     $version = \Ip\Application::getVersion();
     $parts = explode('.', $version);
     if (empty($parts[1]) || $parts[0] < 4 || $parts[1] < 2) {
         throw new \Ip\Exception('ImpressPages 4.2.0 or later required');
     }
 }