Symptoms
System updates installation fail:
ERROR: Declaration of PleskExtWpToolkitControllerAction::apiResponse(array $data = [], string $status = '', string $message = '') must be compatible with PleskExtWpToolkitControllerActionRemoteServersTrait::apiResponse($data = [], $status = '', $message = '') (Action.php:439)
The same error is displayed when accessing Extensions > My Extensions > WordPress > Open.
Cause
Outdated WP Toolkit does not work with sw-engine PHP 8.0 that was installed with Plesk update 50.
Resolution
Try either of the following: