Because Steam automatically updates games to the latest version, you must use the Steam Console to retrieve this specific historical build. Steam Community Enraged Koala - Starbound Wiki 21-Jun-2017 —
If you download Starbound v. Enraged Koala, you can install: Starbound v. Enraged Koala download for computer
Why do players risk security issues for an outdated version? Because Enraged Koala had mechanics that were removed in later updates: Because Steam automatically updates games to the latest