This is the latest gameconfig.xml by @dilapidated, @PNWParksFan, and the RDE Team. A modified gameconfig is required for most add-on mods. We recommend installing this gameconfig using LML (Lenny's Mod Loader). If you are using LML, you can install this package using the Mod Manager, and it will load a working gameconfig.xml for the latest game version. You do not need to change the file in update.rpf, just load this package and you're ready to go.
You can also install this gameconfig manually by downloading the file, and copying gameconfig.xml from the "latest" folder to [mods]\update\update.rpf\common\data\.
Please see our github repository for further information and faster updates after new game versions are released.