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The Lost Cities - DevTool

Build Lost Cities packs in game, or open one you already have. Write your files with comments and .json5, and have mistakes caught at load time with a line number. Small bugs have optional fixes. KubeJS compatible.
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lostcities_devtool-1.21.11-3.2.0-9.x.jar

File namelostcities_devtool-1.21.11-3.2.0-9.x.jar
Uploader
RinkyNoobleRinkyNooble
Uploaded
Nov 7, 2026
Downloads
6
Size
392.2 KB
Mod Loaders
NeoForge
File ID
9484421
Type
R
Release
Supported game versions
  • 1.21.11

Curse Maven Snippet

NeoForge

implementation "curse.maven:the-lost-cities-devtool-1654265:9484421"

Learn more about Curse Maven

What's new

3.2.0-9.x

For The Lost Cities 9.4.0 to 9.5.6, on Minecraft 1.21.11 with NeoForge 21.11. Needs Java 21 or newer.

The DevTool on NeoForge for the first time. Everything in 3.1.2-7.5 is here, with no new commands and no new settings, and every fix applies on every 9.x version.

Your game Your Lost Cities Download
1.21.11, NeoForge 9.4.0 to 9.5.6 3.2.0-9.x
1.21 or 1.21.1, NeoForge 8.0.0 to 8.4.6 3.2.0-8.x
1.20.1, Forge 7.5.1 to 7.5.6 3.1.2-7.5-beta
1.20.1, Forge 7.4.12 3.0.0

Minecraft 1.21.11 needs its own file, because it renamed code the other versions share.

The workshop catalogue and the key reference describe 9.5.6. On an older 9.x, /lcdev workshop go says so, and any key your version does not read is ignored.

Different from Minecraft 1.20.1

A wrong-typed field in a pack file now stops the server. On 1.20.1 Lost Cities ignored it. On 1.21.11 Minecraft refuses the file at startup and names it. That covers a monorail part written as a list, a word under top or floor, a number under top, and a true or false under floor.

The load check now says this, and it flags "top": 1, which 1.20.1 accepted. Lost Cities only reads these files when the server starts, so an edit like this shows up on /reload as a warning about your next restart.

This mod has no additional files