Why?

Maybe I wasn't clear enough, sorry, english isn't my native language : I have some albums that are mastered in 24 bit / 96 KHz (flac) and when I try to play them on my sonos system (arc + sub + one sl as surrounds to be complete), the S2 app tells me the system can't read 96 KHz files. It appears that poeple have been asking the 96 KHz support by sonos for a while now and I was wonering if there were any progress on that matter.

Just do a one-off conversion of your files to a sample rate Sonos can handle - 48kHz.. There will be no difference audible to the human ear. 

Also if you convert them to a reasonable format your bandwidth requirements will be far less.

It’s unlikely that 24/96 support will be added.

I think it is unethical to recommend moving the music collection that we have stored in 96 Khz to 48 Khz Flac. I don't know if it's too complicated for Sonos engineers to update to be able to play 96 Khz flac files, or if they don't know how to do it. (Spanish translation)

Unethical?  The only unethical thing going on here is the music companies pushing hypersonic frequency response as some type of benefit to the music:

https://people.xiph.org/~xiphmont/demo/neil-young.html