I have a bungeecord network, and I wanted to have multiple versions that can connect to the server. Like not just a strict 1.12.2 mc version, from 1.11 to 1.12.2 server version, and also, my server version is 1.12.2.
Via version: let newer version join Via backward: let older version join (1.9+) Via rewind: let very old version join (1.7-1.8)
Not sure about forwards, but I know protocol support goes backwards. It's the updated version of Via Versions