Hi @GinaR,
In this case, we need to distinguish UNII-4 and UNII-5 since 4 relates to 5 Ghz band, and UNII-5 is already considered 6 Ghz (although technically, the first usable channel starts on 5.945) mark. I checked it with my CW9178I in Europe, and in 6 Ghz I can select UNII-5 channels, so that means that UNII-5 are supported.
When it comes to UNII-4, these channels are greyed out, and here I'm not sure if this is because the AP don't support it, or the regulatory domain doesn't allow it. From what I'm reading, it seems like UNII-4 is not supported in many regions, and on top of that, UNII-4 channel ends on 5.925, which is quite close to the UNII-5 at 5.945, which can potentially create sideband interference. Again, not sure if that's the case here since I couldn't find any official confirmation, but my "educated guess" is that UNII-4 isn't supported.
I hope that makes sense, and always happy to be corrected if someone has something to add 😉
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