Go into the partition (drive letter) where your game is installed, then head to "your drive letter:\SteamLibrary\steamapps\workshop\content", locate the folder named "227300" (that number is the App ID that the game was given by Steam), find the folder named "718966063" (this is the Workshop Mod ID) and inside it you'll find a text file named "versions.sii" which you must open (using anything from Notepad to Word etc.) since a few things need to be added.



Do the exact same thing as above and remember that even though the Mod ID will be the same number since the mod itself is for both ETS2 and ATS, the folder name located in your drive letter:\SteamLibrary\steamapps\workshop\content" will now be named "270880" as that is this game's App ID on Steam (also the game version is the same as "Euro Truck Simulator 2", specifically v1.54).



To avoid any confusion and to prevent leaving walls of text here, I will instead leave a photo of exactly how your final text should look like after being edited so that you know for sure that the mod is going to work in-game. Basically, all you need to do is copy and paste any line found all the way down and below "package_version_info : .150" in the text file and paste it under the last line that looks like this - compatible_versions[]: "1.51.*" - while afterwards modyfing the line to either the last version, namely 1.54, or if your file is missing multiple lines between your new compatible_versions[]: "1.54.*" line and the previous one (let's assume the previous one is 1.52) then you'll have to make a 1.53 as well to compensate every single update the game has gone through (1.51 was just for reference since I already updated mine and I can't remember the last version that this mod officially supported).



To make sure everything was done correctly, here is a photo[i.postimg.cc] of my personal updated text file that finally works like a charm again (only the last part matters, specifically everything below package_version_info : .150, but I included everything from package_version_info : .143 to the last line, just in case and for a potentially better understanding of what's what on the user side of things).