How can I allow 1.11 players to join a 1.14 server?

Hi!
I have a question:

How can I have multiple versions on my server? I want my friends to be able to join the server on a lower version, having the new features.

Could you tell me how?

Thanks

But that plugin works the other way around, doesn't it?

It lets newer version players to connect to older servers, doesn't it?

Ok, thanks!