Chromecast Audio with new Firmware

[octaviars]

So the Devialet has two optical inputs 

S/PDIF TOSLINK optical connector:
Formats supported: 16-bit/44.1 kHz PCM to 24-bit/192kHz PCM
3.5mm mini-jack S/PDIF optical + RS232 connector:
Formats supported: 16bits/44.1kHz PCM to 24-bit/96kHz PCM
Device control via the bidirectional RS232 protocol up to 115200 bauds (documentation available via the configurator)

the chromecast has a 3.5mm mini jack that supports 24-bit/96kHz
So am i best getting a 3.5 to 3.5 or a 3.5 to s/pdif?

I run mine with 3.5 to s/pdif but it would not matter right now as both inputs on the Devialet can cope with 24/96 and my TV is connected to the 3.5 input on my Devialet so the only choice was 3.5 to s/pdif.