Direct answer

Build 42.20 is the public Stable line. Treat it as a new season: Build 41 and 42.19 worlds stay on their matching branches, while new 42.20.x worlds get the expanded map, basements, animals, deeper crafting, refreshed traits and occupations, and the official mod manager.

Do this first

  1. Back up any world before changing Steam branches.
  2. Keep a Build 41 world on legacy41 and a 42.19 world on the 42.19 branch.
  3. Start a separate Stable world for Build 42.20 content.
  4. For multiplayer, confirm the server and every client show the same 42.20.x version.

The stable update is bigger than a patch

The official feature overview describes a doubled map surface, reworked towns, new towns, underground spaces, animals, workstations, new skills, and broad interface changes. That scope is why old saves and old route knowledge need deliberate handling.

  • Map: reworked locations, three new towns, taller structures, and basements.
  • Survival: domestic and wild animals, hunting, food production, and long-term loops.
  • Crafting: searchable recipes, workstations, selectable inputs, and blacksmithing.
  • Interface: an official mod manager plus refreshed multiplayer and controller screens.

What the version number means

42.20 identifies the Stable milestone; later 42.20.x releases are hotfixes on that line. A same-line hotfix is not the same thing as migrating from Build 41 or 42.19. Identify the source version of a save before deciding what to do.

  • Build 41 world: preserve on legacy41.
  • 42.19 world: preserve on the 42.19 branch.
  • 42.20.x world: back up, then follow current Stable unless an official warning says otherwise.

Where to go next

Use the returning-player guide for gameplay differences, the save matrix for world compatibility, and the multiplayer desk when an update leaves clients, servers, or mods out of sync.

FAQ

Quick answers

Is Build 42.20 the normal Steam version?

Yes. The developer announced 42.20 for the public Stable branch. Verify the exact current hotfix in the game and server logs.

Can Build 41 saves open in Build 42.20?

No. The release notes direct Build 41 players who want old worlds to legacy41.

Evidence log

Sources checked

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

OfficialProject Zomboid Build 42.20 Released

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

OfficialFeatures Overview: Build 42.20

Official overview of the expanded map, new towns, basements, animals, crafting, occupations, traits, mod manager, and multiplayer UI.

OfficialB42 Checklist

Official pre-launch checklist confirming that Build 41 saves do not carry into Build 42.