American Truck Simulator (ATS) Update 1.39, released in November 2020, was a major milestone that introduced highly requested features, including the Freightliner Cascadia® and the Cabin Accessories DLC. The "Story" of Update 1.39

Mod Adaptation: Many older mods require 1.39 specifically because subsequent updates (like 1.40) introduced major lighting system overhauls that broke older sound and graphics mods.

To download American Truck Simulator (ATS) version 1.39, you must use the Steam Beta

Official Method (Steam - Betas Tab)

  1. Open your Steam Library.
  2. Right-click American Truck SimulatorProperties.
  3. Go to the Betas tab.
  4. In the dropdown menu, select "temporary_1_39 - 1.39.x for legacy mods".
  5. Steam will automatically downgrade your game to 1.39.5 (the final build of that version).

Steam will automatically begin downloading the files for version 1.39. Why Downgrade to 1.39? Players typically revert to 1.39 for two main reasons:

New Content: This version paved the way for the Freightliner Cascadia® and the Cabin Accessories DLC. How to Download and Access Version 1.39