New Minecraft servers are created every day, but not all new Minecraft servers are actually running latest version of Minecraft, which would be 1.16. There’s a plugin for Minecraft servers that allows one server to support multiple versions of the game, it’s called ViaVersion. It’s now possible to setup Minecraft server that supports whole range of clients from version 1.7 to current latest version 1.16.1.
How can you tell if Minecraft server is actually using newest version of Minecraft? In some cases that’s not easy, first step would be to actually check if you can even join the server using latest version of Minecraft. After that you gotta find out if they’re using latest Minecraft or just ViaVersion. This can be done by joining the server and looking around, you should look for items that are only available in your version of Minecraft. For example if you join the server and you can find and use Netherite then that pretty much guarantee’s the fact that that server is actually using Minecraft 1.16.
Beware some servers can render and sent all kinds of items to the player or client, so if you can’t actually use newest items, like mine them or put them in your inventory, then the server is likely using older version combined with ViaVersion plugin. To find newest Minecraft servers check out minecraft server list, just be sure to also check server version.