code: public static function isMobilePhoneNumber($phone)
      {
          $phoneNumber = substr(Tools::removeSpace($phone), -9, 1);
  
          return (!self::isCzechPhoneNumber($phoneNumber) || ($phoneNumber === '6' || $phoneNumber === '7'));
      }
docs: Check if the phone number is mobile
  
  @param string $phone Phone number
  
  @return bool Is phone number mobile
  @static