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The Backrooms Project DeltaMinecraft modpack for 1.21.1

A large Minecraft Backrooms map where you play as a scientist named James Rider who falls into the Backrooms...

newest supported 1.21.1HorrorExtra LargeHardcoreMap Based
Latest version
The Backrooms-Project Delta-v4.0
Minecraft
1.21.1
Java
Java 21+
Loader
Fabric
Licence
not stated
Downloads
2.5k
Updated
4 mo ago
Available on
CurseForge
Space NodeOur hosting

Host The Backrooms Project Delta servers

One click and The Backrooms Project Delta is installed with the right loader, on hardware built for it.

  • 1.21.1
  • Fabric
  • One click modpack install
  • Dependencies handled
  • Tuned startup flags
  • NVMe SSD
Deploy a serverFrom €0.90 per GB

Screenshots

Click a screenshot to open it. Screenshots are served from the author’s own host and belong to them.

Minecraft versions

Every version The Backrooms Project Delta declares support for, newest first, with the Java runtime that version needs.

Other modpacks
MinecraftThroughJavaEvidenceReleased
1.21.1Fabric21+declared8 Aug 2024

Download

From The Backrooms Project Delta’s own host. Nothing is re-hosted here.

The Backrooms-Project Delta-v4.0release29 May 2026

The Backrooms-Project Delta-v4.0.zip · 295.7 MB · for 1.21.1

Download latest
ae804ff001bb…
Older versions5
  • The Backrooms-Project Delta-v3.026 Apr 20261.21.1242.0 MB488 downloadsa890754051d7…Get
  • The Backrooms-Project Delta-v2.117 Apr 20261.21.1234.1 MB25 downloadsb6cd3e9c4774…Get
  • The Backrooms-Project Delta-v2.015 Apr 20261.21.1238.5 MB55 downloadsbfeb857c6d73…Get
  • The Backrooms-Project Delta-v1.111 Apr 20261.21.1224.4 MB61 downloads96961158b5be…Get
  • The Backrooms-Project Delta-v1.03 Apr 20261.21.1224.4 MB145 downloads1b7bc8fd2496…Get

Frequently asked

Does The Backrooms Project Delta work on Minecraft 1.21.1?

Yes. 1.21.1 is the newest Minecraft version The Backrooms Project Delta declares support for, and the claim comes from the author's own release metadata rather than from a compatibility list somebody maintains by hand.

Which platform or loader does The Backrooms Project Delta support?

Fabric. A build for one platform or loader will not necessarily load on another, so this is the first thing to check before the Minecraft version.

Which Java version do I need for The Backrooms Project Delta?

On the newest Minecraft version it supports, Java 21 or newer. The requirement comes from the Minecraft version you run rather than from the modpack itself, so on an older supported Minecraft the answer is that version's Java, not this one.

How do I install The Backrooms Project Delta?

Use a launcher that imports packs, such as Prism Launcher, the Modrinth App or the CurseForge app, and open the pack file with it. The launcher installs the right loader and mods for you; installing a pack's mods by hand is the error-prone way.

Where do I download The Backrooms Project Delta safely?

Start with the author's page on CurseForge, which is where the data here is synced from. MCReference does not host or repackage files. The download link goes to the source recorded for that release; verify the publisher, filename and checksum before running it.

Works on the same versions

Ordered by how much of the recent Minecraft version coverage overlaps, not by popularity.

Re-ConsoleA continued Legacy Console Edition experience, expanded upon with modern Java Edition content and QoL! (An Official Legacy4J Project)MAX FPS: Optimized🚀 MAX FPS WITHOUT UNNECESSARY MODS! Only 16 optimization mods - NOTHING EXTRA! ✅ ALL MAJOR VERSIONS ⚡ INSTALLS ON ANY LAUNCHER! (Guide below)PacktrixPre-packed Official Modpack containing Patrix Resource Pack for easy install using Fabric/Quilt.Simply Optimized ReloadedAn unofficial port of Simply Optimized built to support every major mod loader and stay current with the newest versions of Minecraft.ElixirA well-researched performance & optimization modpack to make the game run smoother! With shader & Fresh Animations support. 26.3 ✔OptimumFuse[1.21.5] [Fabric📜] An open-source modpack that improves the game's performance and visuals, inspired by OptiFine, while staying true to the vanilla Minecraft experience.

Last checked 1 mo ago against CurseForge. We do not host files and we do not republish descriptions; every download link points at the author’s own release.

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