Special combinator to give information about items, fluids, receipes etc
Mods introducing new content into the game.
Entities which interact with the circuit network.
When joining my server it says the following mod even handlers are not identical between you and the server.
Thanks for the report, I'll take a look at it. I haven't tried multiplayer before so it might take me a few days.
Give it a try now maybe? I think I fixed the bug but I haven't set up a proper server to test yet.
You don't really need a server. Copy the Factorio installation to another folder, run both Factorios locally, host on one, join on the other. Also great when you want to play multiplayer but have no friends.