After testing over 12 sources, we have found the Google Drive link for ETS2 1.39. Here is everything you need to know.
For mods to work properly, right-click eurotrucks2.exe → Properties → Compatibility → Run as admin.
If you own the game on Steam, you can easily revert to version 1.39 using the "Betas" feature: and go to your Library .
You cannot simply "downgrade" via Steam easily without jumping through hoops (Steam Console beta codes). If you try to download from random upload sites (UploadHaven, Rapidgator), you face: