CurseForge · Minecraft mod
Subterranean Expansion | Cave Update
Overhaul of underground caves in the overworld.
Quick answer
Which Subterranean Expansion | Cave Update release should I use?
Subterranean Expansion | Cave Update sub_expansion-1.1.1-NeoForge-1.21.1.jar targets 1.21.1 with NeoForge. The project page does not say whether this file belongs on the client, dedicated server, or both. No extra mods listed for this file.
Where it goes
Is Subterranean Expansion | Cave Update required on the client, server, or both?
The project page does not say whether this file belongs on the client, dedicated server, or both.
The source does not explicitly classify this release as client-only or server-only.
What else does Subterranean Expansion | Cave Update sub_expansion-1.1.1-NeoForge-1.21.1.jar need?
sub_expansion-1.1.1-NeoForge-1.21.1.jar. Change the file and its required mods may change too.
This file does not list any required mods. Do not add a library just because a different file uses it.
This file does not list any required or optional mods.
Before you install it
Add Subterranean Expansion | Cave Update without breaking your instance.
Built for Subterranean Expansion | Cave Update sub_expansion-1.1.1-NeoForge-1.21.1.jar. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use sub_expansion-1.1.1-NeoForge-1.21.1.jar. It targets 1.21.1 with NeoForge; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
The project page does not say whether this file belongs on the client, dedicated server, or both.
- 04
Pick the file you checked
Use the “Get this file” button beside sub_expansion-1.1.1-NeoForge-1.21.1.jar. It opens that exact file at the source.
About this project
What does Subterranean Expansion | Cave Update add?

About Subterranean Expansion:
Subterranean Expansion enhances the underground experience of vanilla caves by introducing new natural features and unique cave environments to bring you the cave update we all actually wanted.
Stalagmites & Stalactites: 
Stalagmites and Stalactites of all vanilla stone variants, and even some custom stone variants.
<details> <summary>Stalagmites & Stalactites</summary>
In Release 1.0.0:
- Stone Stalagmite/Stalactite
- Mossy Stone Stalagmite/Stalactite
- Granite Stalagmite/Stalactite
- Diorite Stalagmite/Stalactite
- Andesite Stalagmite/Stalactite
- Deepslate Stalagmite/Stalactite
- Tuff Stalagmite/Stalactite
- Sandstone Stalagmite/Stalactite
- Deep Sandstone Stalagmite/Stalactite
- Calcite Stalagmite/Stalactite
</details>
Update 1.1.0: Frosted Caves

IMPORTANT INFO:
This mod is a passion project that doesn't have a whole team behind it. We expect there to be bugs and we will try to fix them. The mod is still in active development and is planned to add more features. Other than that, enjoy our mod! ##
Recommended mods:
You should stock up on worldgen optimization mods, as this mod tends to slow it down a bit due to the added complexity. Here are a few:
FAQ:
Is there a config file?
As of update 1.1.0 there is.
Will you port to X mod loader?
No. We are going to currently use Forge for 1.20.1, although we are not opposed to do so in the future.
Where can I report bugs?
You can report in the issue tab.
Can I use this in my modpack?
Yes.
I have a suggestion, how do I suggest it?
You can suggest it in the issue tab with the suggestion tag.
Project description from CurseForge.
Pick your setup
Subterranean Expansion | Cave Update by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.20.1
1 loader buildCheck the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
Subterranean Expansion | Cave Update versions and loaders
sub_expansion-1.1.1-NeoForge-1.21.1.jar
17 Aug 2026
sub_expansion-1.1.1-Forge-1.20.1.jar
17 Aug 2026
sub_expansion-1.1.0-NeoForge-1.21.1.jar
13 Aug 2026
sub_expansion-1.1.0-Forge-1.20.1.jar
13 Aug 2026
sub_expansion-1.0.1-neoforge-1.21.1.jar
24 Sept 2025
sub_expansion-1.0.1-forge-1.20.1.jar
24 Sept 2025
sub_expansion-1.0.0-neoforge-1.21.1.jar
20 Sept 2025
sub_expansion-1.0.0-forge-1.20.1.jar
18 Sept 2025
Looking for an older file? The official CurseForge project page is in Resources.