Build 41 introduced massive multiplayer improvements, allowing for dedicated servers and seamless co-op. Playing Co-op (Build 41.77.9)
Download the tool from the "Tools" section of your Steam Library. Edit the servertest.ini files to customize your experience. Why Avoid "Free" Download Sites? Project Zomboid Free Download (v41.77.9 Co-op)
If you own the game, you can set up a co-op session with friends using several methods: 1. In-Game Hosting (Easiest) Build 41 introduced massive multiplayer improvements