Patch to enable offline LAN multiplayer? Not connecting to shift Mac OS

Hi, I saw a file floating around from a few years ago, that makes is so LAN multiplayer works offline. Does anyone have this? I just want to multiplayer with my girlfriend in our house. We use Macs. Also does anyone know why it won’t connect to Shift? None of the multiplayer options are working. Thanks!

Edit: I did already set the network connections to “allow incoming connections” but that didn’t work.