For Expert product:
To stream music to a Devialet you will first need a dedicated network. Please find more information about how to set up an optimized network here
In such a configuration, you can connect your Devialet via Toslink to your Airport Express. Now you can use the Air-Play to stream music to your Devialet.
For Expert Pro with the Core Infinity:
We are going to add the Airplay protocol as a regular way to stream music