Fatal error: Uncaught Error: Interface "clientSingleton" not found in /volume1/web/packages/system/lib/class/module/module.old.php on line 3

Error: Interface "clientSingleton" not found in /volume1/web/packages/system/lib/class/module/module.old.php on line 3

Call Stack:
    0.0002     359680   1. {main}() /volume1/web/packages/system/lib/class/module/module.old.php:0