The V1.39 update, released officially in late 2020, brought several "ground-up" reworks to the base game:
For users with the legacy (non-Steam) version, you must use the official SCS Software Updater to manually download the patch files. Why Downgrade to 1.39? Euro Truck Simulator 2 V1-39 Download
How to install and update via Steam (most common) The V1
Select temporary_1_39 - 1.39.x for incompatible mods from the dropdown menu. The V1.39 update
From the drop-down menu, select temporary_1_39 - 1.39.x for incompatible mods .
Update 1.39 was focused on three main pillars: enhancing the heavy cargo experience, updating the game’s UI, and refreshing older map regions.