Overview
*There is obviously a limit to how complicated the mods are because I imagine eventually the game would lose its mind if the changes are too intricate. However things like identically configured Darthmods are by all means possible.
UNDERSTANDING HOW THE GAME LOADS FILES
Through some testing, me and my friends have finally realized that in order to avoid the “incompatible versions” error (this does not include errors created by other files or issues not related to mods in any way) All you have to do is make sure that all the mods listed in the launcher appear in the same order.
For some reason when the game loads these files it will try to communicate with the other player’s game version and if it sees any discrepancy, it will throw the incompatible versions error. It doesn’t care that the files is actually there, just one line under, no. It will not cooperate if the order is in any way changed.
HOW TO WORK AROUND IT
I cannot guarantee that this will work but we have been using this method for a while and it seems to be working reliably pretty much every time. There are still some quirks that may occur which are beyond our control, but these unforseen circumstances are few and far between. The way this is going to work is, you will start from the final step becuase in theory it should be enough and if it doesn’t work, simply use two final steps, three final steps if just the two don’t work, etc. If you don’t care about cutting corners and you prefer to be thorough, just perform all of the steps from start to finish.
Remove the AppData/Roaming/The creative assembly/Shogun 2 folder (it will remove all your saves and game settings, you can alwyas back up the folder for when you stop playing together)
Unsubscribe and delete all the mods from the Shogun 2 data folder (steamapps/common/Total War SHOGUN 2/data) these would be all the files that are listed in your launcher when you select the mods you wish to activate, their names will be the same.
You and whoever you want to play with, subscribe to all the worskhop mods you want in your game in the same order.
Verify integrity of the game cache.
Launch your game without any mods activated and choose all your graphical settings etc. then close your game.
Your mods should in theory be listed in the launcher in the same order as the person you want to play with. (Not sure whether this is important or not, could be it isn’t)
Activate the mods on the list, one by one, in the same order as the person you want to play with (based on its name, not order in which they appear on the list). Launch the game and hope for best.
AFTERWORD
If everything went well, you will be able to join each other’s game and launch it without any issues. There shouldn’t be any problems with stability when playing together, although mods of lower quality which would sometimes cause your game to crash even in singleplayer might obviously do the same in multiplayer.
If you get the same error in later Total War games, such as ROME 2 and ATTILA, this method should theoretically work as well, although we never tried.
This guide is a “work in progress”, in other words we stick to what works for us. We don’t perform extensive tests to check every single possibility and scenario. What we have managed to gather so far, I put in the guide as is. If you happen to run any tests, intentionally or otherwise, or manage to figure anything else out as you try to play with your friends, please put it in the comments, maybe somebody else will test its viability or it will help others in figuring out a more efficient method.
Hope this helps you and good luck.