Free Download (v41.78.12 Co-op): Project Zomboid

It sounds like you might be looking for information about a specific "free" version of featuring co-op play.

and how to set up a legitimate co-op server on the current version? Project Zomboid Free Download (v41.78.12 Co-op)

To make sure I'm giving you the right help, could you clarify what you need? For example, It sounds like you might be looking for

for the co-op/multiplayer features within that specific version? Project Zomboid Free Download (v41.78.12 Co-op)