Please find the latest release notes on Steam: Release notes
The latest build is automatically downloaded by the Steam client or GOG Galaxy client. GOG users not using GOG Galaxy can download the latest build in the GOG games library.
To verify that you are using the latest build, compare the build number displayed in the bottom right corner of the main menu with the latest build number in the release notes on Steam.
If you want to try out new features and help us testing the stability of new versions, upcoming patches can be accessed in advance by using Steam branch “testing”.
To switch the branch, close the game and right click Transport Fever in your Steam library and selected “Properties”. Under the “Betas” tab you can select “testing” from the pulldown menu. This can be reverted anytime.
The “testing” version is equal or newer than the current release version on the main Steam branch. Please note that the testing version might not be stable, so you should always save your game under a new name when using it. More information can be found in the Transport Fever testing group. Feel free to join the group and discuss upcoming patches.