What's the difference between "LEGACY" and "OLD" versions ?
I'm playing version 1.3 public . . . So, which version do I need ?
The LEGACY label is for the last builds that were compatible with the old scripting system (versions of the game from before 1.4.0).
The version number indicates the minimum version required, and the v? number is the iteration, so if you're on 1.3.0, you would have to download b120v4.
That said, I really don't recommend sticking to pre-1.4 mods. The 1.4.4 demo is using the new scripting system and allows you to use more recent versions of my mods.
https://www.patreon.com/posts/public-release-1-111593601