The question wasn’t whether RAAT was supported but how.
The Zen Stream was supposedly RR but still showed bridge status on is device setup page (while showing SDK on another):
I have no idea if this was fixed by iFi as I sold my ZS long ago. It also could very well have been nothing more than a cosmetic error/bug but iFi’s track record with this particular product makes it hard to give them the benefit of the doubt, even when talking about the new version.