code: protected function is_php($version)
      {
          static $_is_php;
          $version = (string)$version;
  
          if (!isset($_is_php[$version])) {
              $_is_php[$version] = version_compare(PHP_VERSION, $version, '>=');
          }
  
          return $_is_php[$version];
      }
docs: Determines if the current version of PHP is equal to or greater than the supplied value
  
  @param    string
  @return    bool    TRUE if the current version is $version or higher