When we buy a wifi router, the specs are written in a nonsensical way, which are not understandable by common people. In the past, Wi-Fi versions were identified by a letter or a pair of letters that referred to a wireless standard. The current version is 802.11ac, but before that, we had 802.11n, 802.11g, 802.11a, and 802.11b. So now, Wi-Fi is adopting version numbers so that it’ll be easier to tell whether the router or device you’re buying is on the latest version.
So instead of the current Wi-Fi being called 802.11ac, it’ll be called Wi-Fi 5 (because it’s the fifth version). It’ll probably make more sense this way, starting with the first version of Wi-Fi, 802.11b. Now, instead of wondering whether “ac” is better than “n” or if the two versions even work together, you’ll just look at the number. Wi-Fi 5 is higher than Wi-Fi 4, so obviously it’s better.
Wifi networks always work together so in the future when you connect to a Wi-Fi network on your phone or laptop, your device will tell you what Wi-Fi version you’re connected to. That way, if two networks are available — one showing “4” and the other showing “5” — you’d be able to choose the newer, faster option.