https://thenextweb.com/tech/2018/10/04/wi-fi-6-introduced/

For years, the names of Wi-Fi standards have been needlessly complex. It can be hard to remember which one your router supports – is it 802.11n or 802.11ac? Thankfully, the Wi-Fi Alliance – the organization which certifies Wi-Fi products – has introduced a simpler nomenclature that should make it easier to tell these standards apart.

The rebranding applies to existing Wi-Fi standards as follows: