Steam Codes?

[GuessingEveryDay]

Whenever I see my Betas in KSP Steam, I can see that there are options to go back to 1.4 and before that, so I would like to try those out, because a lot of my favorite mods often work the best in 1.4 and whatnot, but it says I need the right codes to access those betas. Any help?

[KerbolExplorer]

Most of the times you can get older versions throught the steam console:

https://www.reddit.com/r/Steam/comments/611h5e/guide_how_to_download_older_versions_of_a_game_on/

From what I seen KSP goes all the way down to 1.2.2 so you should find the versions you want.

[GuessingEveryDay]

But it says that I need to enter a password to access the betas. Called "beta access code".