The latest WiiM Mini firmware now supports AirPlay lossless up to 16/44.1. WiiM is apparently asking Apple for permission to support up to 24/48 lossless.
RME test files show that the WiiM, via its optical port, is bit-perfect. It should therefore now measure -96dB vs the measured 90.5dB using AirPlay from a proper server such as LMS.
LMS, of course, also supports what is surely the most widely-used digital audio protocol, UPnP. Highly unfortunate that Roon refuses to support it, IMO. The RME test files verify that the WiiM Mini is bit-perfect using UPnP via its optical port up to 24/192.
AirPlay, 16/44.1
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UPnP, 24/192
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