Steps:

1. Go to your Steam library

2. Right-click on the title of "The Life of Greather" on the left side of your page.

3. Click "Properties"

4. A window should pop up, navigate to the far right tab at the top of the newly opened window, which should say "Betas" and click on it.

5. There should be a button that says "Opt out of all beta programs", click that, and click version 1.1.5(speedrunning) -

6. Let the game update and you should now have access to Version 1.1.5!