I have a few of the Chromecast Audio units that Kogan were selling as factory refurbished back in 2020 after the product was discontinued. They work fine but when setting up I get the message "This Chromecast Audio was manufactured for a different country, and may not be compatible with your Wi-Fi network."
In the device information page on Google Home app I see the Country code is CA (Canada I guess). Firmware version is 1.56.281627 which appears to be the latest.
I haven't seen problems but I haven't tried connecting to 5GHz which I understand is where people sometimes have problems (due to the potentially different channels in use in different countries).
Is it possible to change the country code to prevent the above message? I tried factory resetting but that didn't change anything nor provide an option to choose the Country.
I think that message means that wifi channel 13 is not used in America/Canada, but it is used in Australia. So as long as your wifi is channel 1-11 the CC Audio will correct no problem.