Players get "Workshop item version is different than the server"

This message means a mod was updated on Steam and your players already have the new version, while your server still has the old one. The server only downloads mod updates when it starts. Restart the server and the players can join. The message does not say which mod it is.

Fix it now

1. Check the panel. A notification says a Workshop mod was updated, and the Activity log says "Steam Workshop update for" followed by the mod names and "Players on the new version cannot join until the server restarts".
2. Restart the server. Warn players first: How to send a message to everyone on your Project Zomboid server.
3. The server downloads the new version while it starts. When the badge says Online, ask the player to try again.

Stop it happening again

Turn on Restart when a mod updates on the Workshop tab. The server then restarts for you, with warnings: How to restart your Project Zomboid server when a mod updates. Or restart on a schedule: How to schedule restarts and backups for your Project Zomboid server.

If it keeps happening after a restart

• The mod may not have downloaded: look at [playnhost] Workshop Items verified and applied: in the Console. An item that failed to download is dropped with a pnh-workshop-check: WARNING line.
• Run Check Mod Updates from Quick Tasks, then read the answer in the Console.
• A player may have a different mod list. Everyone needs the same mods: Your Project Zomboid mods do nothing.

More join checks: Players cannot join your Project Zomboid server.