Because 11.3.0 is the latest version on the mod portal, third-party servers that auto-update pull that version. This causes servers to be unable to launch. Could you have the 2.0 version as the latest version of the mod?

Are you talking about the official server binary or some other thing? Either way id say this is more of an issue of the server, as 11.3.0 is explicitly marked as only compatible with factorio 1.1, so it should be ignored on other versions of the game.

I have a server hosted on Indifferent Broccoli. When the server downloads mod updates, it pulls 11.3.0 because it just assumes the latest version on the mod portal is compatible with the latest version of the game. I assume this is also what happened with the other user who mentioned the mod being suddenly incompatible with 2.0.

Im gonna stick with "this is a problem of the server/hosting provider, not mine". The game client handles this correctly and the official server doesn't have mod update functionality afaict, it can only sync mods with a save file, which will download the exact version in the save. This means theyre probably using the mod portal api to update mods, so it's on them to respect the defined factorio_version (which was present in the api last time i checked) and if they don't it's their responsibility to fix it.

Also the latest version on the mod portal being compatible with the latest version of the game is not a valid assumption even in perfectly normal situations - what if there is no 2.0 version of the mod for example?

I've no clue how it works. I just wanted to bring it to attention, thank you for your time anyhoo.

You can try reporting this to indifferent broccoli, maybe theyll do something about it. Feel free to link or quote this thread as you wish.