I know there was a documented issue earlier this year where a new version of the Spotify app caused Wiim devices to no longer appear in the list of available playback devices. Supposedly, this was resolved shortly thereafter by a subsequent Spotify app update, but the problem persisted for me despite multiple Spotify app updates.
In truth, I think my issue was actually caused by setting up a new mesh wifi network in my house (TP-Link Deco XE75 pro), which seemingly somehow convinced the Spotify app on my phone that it was no longer on the same network as my Wiim Ultra, despite multiple verifications that they were both on the same 5Ghz network and both connecting to the same access point (not that this should matter if everything's working as it should). I tried everything I could think of to resolve this, short of factory resetting the Wiim Ultra (a hassle I really didn't want to go through in terms of having to set up all my presets, PEQ profiles, logins, etc. once again). Ultimately, I resigned myself to just living with it -- I mostly listen to music through Qobuz on the Ultra anyway, and if I really wanted to listen to something that was only on Spotify, there were workarounds (the Spotify app on my TV, or *shudders*... Bluetooth).
That's all to say: I finally found the solution that solved this issue (for me at least). In the Spotify iOS app: Settings>Apps and devices>Local device visibility. This toggle had been switched on (I assume by default) for who knows how long. Switching it OFF allows the Spotify app to use Spotify Connect to play music through devices that it knows of, but that it can't find on the network it's currently connected to. Suddenly, my Wiim Ultra and Wiim Pro both appear as playback options (albeit in an "on other networks" subsection at the bottom of the list). And they work! Immediately I was able to connect and play music through them.
Anyway, it doesn't seem like this is an especially widespread issue at this point, and like I said, I'm guessing it's somehow related to the interplay between this specific Deco mesh network and the Spotify app on my phone (still seems weird, but whatever). And maybe there's some setting buried in the Deco app that would've resolved this some other way. But I'm posting here just in case anyone runs into the same issue, and might find this helpful. Cheers!
In truth, I think my issue was actually caused by setting up a new mesh wifi network in my house (TP-Link Deco XE75 pro), which seemingly somehow convinced the Spotify app on my phone that it was no longer on the same network as my Wiim Ultra, despite multiple verifications that they were both on the same 5Ghz network and both connecting to the same access point (not that this should matter if everything's working as it should). I tried everything I could think of to resolve this, short of factory resetting the Wiim Ultra (a hassle I really didn't want to go through in terms of having to set up all my presets, PEQ profiles, logins, etc. once again). Ultimately, I resigned myself to just living with it -- I mostly listen to music through Qobuz on the Ultra anyway, and if I really wanted to listen to something that was only on Spotify, there were workarounds (the Spotify app on my TV, or *shudders*... Bluetooth).
That's all to say: I finally found the solution that solved this issue (for me at least). In the Spotify iOS app: Settings>Apps and devices>Local device visibility. This toggle had been switched on (I assume by default) for who knows how long. Switching it OFF allows the Spotify app to use Spotify Connect to play music through devices that it knows of, but that it can't find on the network it's currently connected to. Suddenly, my Wiim Ultra and Wiim Pro both appear as playback options (albeit in an "on other networks" subsection at the bottom of the list). And they work! Immediately I was able to connect and play music through them.
Anyway, it doesn't seem like this is an especially widespread issue at this point, and like I said, I'm guessing it's somehow related to the interplay between this specific Deco mesh network and the Spotify app on my phone (still seems weird, but whatever). And maybe there's some setting buried in the Deco app that would've resolved this some other way. But I'm posting here just in case anyone runs into the same issue, and might find this helpful. Cheers!