When Apple announced the HomePod last month, the spec sheet on the Apple website suggested that the HomePod mini has an older version of WiFi, 802.11n which is the last version of the standard to both mean 2.4GHz and 5GHz. When Apple said it supports that version it was never clear if the HomePod mini supports dual band, which wouldn't be surprising as the chip it is running is the S5 from the Apple Watch Series 5 and Apple Watch SE and both of those devices support 802.11n, but only at 2.4GHz.
In our original article, we said:
"Apple has only added ‘802.11n’ to the mini which could mean dual band but it is most likely only going to support 2.4GHz which isn’t that great – we’ll know more when it ships."
Well I have received my HomePod mini today, and I can verify it does indeed support both 2.4GHz and 5GHz at the 802.11n standard. The larger 'OG HomePod' supports 802.11ac at 5GHz and 2.4GHz at 802.11n.
I can verify this as I have a Ubiquiti UniFi system which is an enterprise networking platform and lets you know all the details about every client on the network.
In the above image you can see both my OG HomePod and HomePod mini are connecting at 5GHz channels.
In the client view of UniFi it even tells you the specific standard the device is connecting at, 11na for the HomePod mini and 11ac for the OG HomePod.