To specifically play v3.4.2 , right-click Stellaris in your Steam library, go to Properties > Betas , and select 3.4.2 - Cepheus from the dropdown menu.
If you own the game on Steam, ensure your "Automatic Updates" are enabled to download the latest stable version. Download Stellaris Galaxy Edition v3.4.2 (7836)...
The is the premium version of the grand strategy game, offering exclusive digital content alongside the base game. It includes: To specifically play v3