What do I have to do to get a older Besiege version (v0.20) for Multiplayer Mod?

[BirdyDragon]

I think the Text Above say enouth.
What do I have to do to get the Old version?
Do i have to Post my Steam - ID to conform that i bourght the full Game?
Do i have to tell you my Steam - Name?

I only wanna Play with the Multiplayer - Mod with my Brother.
~Sorry for my English

 

[ITR]

You have to have a backup of an older version of Besiege, I think