Today, I got reply from audioNEXT and they told me that the device has full warranty, because it has never been used by an end customer. It was a so called press example for testing purposes, which is in mint condition. In addition, they told me that the power stage has been replaced due to the fact that old devices might have problems with their GaN transistors. And they enclosed a completely new remote control.
So, the only thing that worries me is the problem with the VU meter.