If you own the game on Steam, you can right-click the game, go to Properties > Betas , and select temporary_1_39 - 1.39.x for incompatible mods .

Official versions automatically manage your DLCs without needing complex file "cracks." Conclusion

If you are looking for the "best" way to play version 1.39, the most stable and feature-rich method is actually through .

Exploring Euro Truck Simulator 2: Version 1.39 and the Codex Legacy