/**
  * Check is compatible package
  * 
  * @return boolean
  */
 private function isCompatible()
 {
     $packageInfo = $this->getViewOptions('package');
     if (isset($packageInfo['compatibility']) && $packageInfo['compatibility']) {
         $compatibility = explode(",", $packageInfo['compatibility']);
         if (in_array(Fox::getVersion(), $compatibility)) {
             return true;
         } else {
             $this->messages[] = "Extension is not compatible with version :" . Fox::getVersion();
         }
     } else {
         $this->messages[] = "Unknown compatibility";
     }
     return false;
 }