- `filebase\system\file\FileDataHandler` (use `filebase\system\cache\runtime\FileRuntimeCache`)
- `wcf\action\AbstractAjaxAction` (use PSR-7 responses, [WoltLab/WCF#4437](https://github.com/WoltLab/WCF/pull/4437))
- `wcf\page\AbstractSecurePage` ([WoltLab/WCF#4515](https://github.com/WoltLab/WCF/pull/4515))
+- `wcf\system\exception\ILoggingAwareException` ([WoltLab/WCF#4547](https://github.com/WoltLab/WCF/pull/4547))
- `wcf\system\io\FTP` (directly use the FTP extension)
- `wcf\util\PasswordUtil`