This will cause some error like "Failed to load modmap" or some error about a mod.
This was the old mod:
Research and Development V2.2c 507355109
http://steamcommunity.com/sharedfiles/filedetails/?id=507355109
The new mod you should have installed from the person who took it over is here:
Research and Development WIP v2.4.1 605096060
http://steamcommunity.com/sharedfiles/filedetails/?id=605096060
Make sure to follow the instructions in the new mod page on how to convert the mods and updating your items in the game.