Volumio as part of the Pro-Ject - Play app

Hello all - my first post here so be gentle on me…

I am using the ProJect Play app - which is based an a light version of Volumio - to control and select music from my Pro-Ject Stream Box S2 Ultra. It works fine but is limited re info on artists and recordings and asks me to upgrade to full Volumio. The Stream Box S2 Ultra is based on a Raspberry PI module I believe. Is the upsampling feature of the S2 based on SOX? It is included in the ProJect Play app but is the quality improved with the full Volumio app? I am also intrigued about the Nanosound CD Upsampling plug in? Any news/views will be greatly appreciated. Thank you.