Since you specifically mentioned version 1.35, it is worth noting what changes you will see upon updating the game:
There are no shortcuts to "generating" a free key; legitimate codes must be purchased or retrieved from official records.
Based on this analysis, we recommend that players:
The code is found inside the CD/DVD case, often printed on a sticker or the manual.
: If you buy the game on Steam , you do not receive a traditional product key; the license is tied directly to your Steam account for automatic updates and management.
Euro Truck Simulator 2 (ETS2) is a live-service game. The version number "1.35" refers to a specific update released in 2019. Since then, the game has updated significantly (version 1.50+ as of 2024). A product key for version 1.35 is simply a standard key for the base game. Once you redeem the key on Steam, the game will automatically update to the absolute latest version (including all free map expansions and physics improvements) at no extra cost.