Direct answer

Read the version from both client and server rather than assuming SteamCMD updated successfully. Stop the server, update the actual install directory, restart, and confirm its log shows the same 42.20.x build as every client before changing mods or saves.

Do this first

  1. Capture the client's exact version.
  2. Stop the server and read its last startup version.
  3. Confirm SteamCMD updates the directory the service launches.
  4. Run the documented update and validation process.
  5. Recheck both versions before file or mod diagnostics.

Version first, files second

A file mismatch can come from different game builds, different mod content, or local file changes. Exact client/server version equality is the cheapest fact to establish first.

The wrong install can update cleanly

SteamCMD can report success for one directory while a service launches another. Compare configured launch and update paths, then use the server startup log as the result.

  • Stop the instance.
  • Confirm install and launch directories.
  • Update and validate the correct installation.
  • Restart and read the new version.

When versions match

Move to Workshop item versions, dependencies, file integrity, and the joining-game diagnostic. Do not disable checksum or security settings as a blanket first step; that can hide evidence.

FAQ

Quick answers

Why does SteamCMD say updated while the server is old?

It may have updated a different install. Verify the path the running service launches and read its startup log.

Can matching 42.20.3 labels still hide a mismatch?

Use the full build or revision from logs when available, then check Workshop files and local modifications.

Evidence log

Sources checked

Official sources establish universal facts; forum and specialist sources are used for symptoms, vocabulary, and cross-checking.

Official forumBuild 42 File Does Not Match Report

Support report showing version mismatch as one reproducible cause of multiplayer file errors; replies remain community advice.

Platform docsSteamCMD Documentation

Platform documentation for installing and updating dedicated server applications through SteamCMD.

OfficialProject Zomboid Build 42.20 Released

Official Stable status, legacy41 instructions, and the explicit Build 41/42.19 save boundaries.