Go to Documents/MyGames/GoatSim/GoatGame/Mods and then choose a binary of numbers.
The numbers represent a mod, so go to the mod page of the mod you want to update, then, in the link it will have the numbers to locate the mod. After this, open the mod files and find a file called 'version'. Open it and you will say an older update. What you'll need to do is remove this update and put in the current update version.
After this open goat sim and be amazed at what you've done, raise a dead mod up from the ground.