Article – From the horse’s mouth
The comments raised by the Wi-Fi Alliance about the fact that 2.4GHz-based Wi-Fi networking technology being a nearly-dead technology is something that I find a bit “too quick” at the moment.
One key issue is that there is still a significant number of Wi-Fi client-side and access-point-side devices which only work on the 2.4GHz band using 802.11b/g/n protocols in circulation. This is more so with mobile devices and specific-purpose devices like consumer AV where an upgrade to a 5GHz technology would be costly if not impossible.
In some situations, the 2.4 GHz band with the longer wavelength compared to 5GHz may be at an advantage when it comes to the longer-wavelength bands and frequencies offering better coverage. This may allow for fewer 2.4GHz access points to cover a space.
So if I was to create a upgrade a Wi-Fi segement, I would look towards implementing a simultaneous dual-band setup which works to 802.11n or 802.11ac on the 5GHz band and 802.11n on the 2.4GHz band. As well, I would prefer to buy or specify devices, especially laptops, tablets and smartphones that use dual band Wi-Fi technology.
As for configuring the networks, the 2.4GHz band would be working as 802.11g/n compatibility mode while the 5GHz band would be at 802.11n or 802.11n/ac compatibility mode. This is to assure greatest compatibility with most of the existing devices that are to work with the network.