How to Downpatch Dark Souls 3 to v1.15

If you try to launch Dark Souls: Archthrones on the current Steam version of Dark Souls III, the game will crash immediately.

This is not a bug; it is an architectural necessity. Archthrones relies on specific memory hooks and pointers that only exist in version 1.15 of the game engine. Subsequent updates by FromSoftware (primarily for server maintenance) shifted these memory addresses, rendering the mod’s DLL injection method incompatible with the modern live version.

To play Archthrones, you must manually “downpatch” your game executable. This guide covers the safe, reversible method to swap your executable without breaking your legitimate Steam installation.

Prerequisites Checklist

Before modifying any game files, ensure your environment is ready. A mistake here can force you to redownload the entire 25GB base game.

• Clean Install: Ensure you have a fresh, unmodded installation of Dark Souls III on Steam.
• The Archthrones Demo Files: You should have already downloaded the demo assets (see our Download Hub).
• Storage Space: Keep at least 50GB free for the extraction and temporary file swapping.
• No Other Mods: Uninstall “Blue Sentinel,” “Cinders,” or “Convergence.” They will conflict with the downpatched executable.

Step 1: Backup Your Save Files (Critical)

Downpatching involves manipulating the game’s core executable. While the goal is to play Archthrones on a private server, you must protect your vanilla save files from corruption or banning risks.

1. Navigate to your AppData folder:
   C:\Users\[YourName]\AppData\Roaming\DarkSoulsIII\
2. Locate the file named DS30000.sl2.
3. Copy this file and paste it into a safe backup folder on your desktop or cloud storage.

Archthrones will eventually create its own save directory (/Roaming/Archthrones), but this manual backup is your fail-safe. For more details on save safety and server segregation, read our Online Safety & Private Server Guide.

Step 2: The Logic (Why v1.15?)

You might be asking why the mod team hasn’t updated the mod to work with the latest version.

The answer lies in Memory Static Addresses. The Archthrones custom script engine hooks into specific lines of code in the DarkSoulsIII.exe to inject new mechanics like Deflection & Posture and the new Curse Rework.

When FromSoftware updated the game to remove the RCE vulnerability in 2022/2023, they recompiled the executable. This shifted every line of code, breaking the mod’s “hooks.” Downpatching simply reverts the “door” (the .exe) so the mod can walk through it, while keeping the “house” (the game assets) largely the same.

Step 3: Acquiring the v1.15 Executable

There are two primary ways to get this file. Since Steam does not offer a native “Rollback” button for Dark Souls III, we must use external tools.

Method A: The DepotDownloader (Recommended)

This method pulls the official, legal file directly from Steam’s backend servers using your own credentials.

1. Download DepotDownloader (requires .NET Core).
2. Open a Command Prompt (CMD) in the DepotDownloader folder.
3. Run the command to fetch the specific depot containing the 1.15 executable. You will need the App ID (374320) and the specific Manifest ID for the 1.15 update.

.\DepotDownloader.bat -app 374320 -depot 374321 -manifest [Manifest-ID-Here] -username [SteamUser] -password [SteamPass]

(Note: You can find the exact historical Manifest ID for v1.15 on SteamDB).

Method B: Community Archives

Many players find the DepotDownloader method too technical. The Archthrones community often archives the DarkSoulsIII.exe (v1.15) specifically for this purpose. If you have obtained this file from a trusted community source, you can skip to Step 4.

Step 4: The Executable Swap

Once you have the v1.15 executable, the installation is a simple drag-and-drop operation.

1. Open your Dark Souls III game directory:
   Steam Library > Right Click Dark Souls III > Manage > Browse Local Files.
2. Rename your current DarkSoulsIII.exe to DarkSoulsIII.exe.bak.

• Do not delete it. You will need to restore this filename if you ever want to play the vanilla game online again.

1. Paste the v1.15 DarkSoulsIII.exe into the folder.
2. Paste the Archthrones mod files (including the dinput8.dll) into the same folder.

Verification: Right-click the new executable, select Properties > Details. The File Version should read 1.15.

Step 5: Preventing Steam Auto-Updates

Steam will detect that your file is “out of date” and attempt to “fix” it by downloading the latest version again, undoing your work. You must stop this.

1. Right-click Dark Souls III in Steam.
2. Go to Properties > Updates.
3. Change “Automatic Updates” to “Only update this game when I launch it”.
4. CRITICAL: Always launch Archthrones via the executable directly or a custom shortcut, NOT through the big green “Play” button in Steam.

If Steam accidentally updates your game, simply repeat Step 4.

Troubleshooting the Downpatch

If you have followed these steps and the game still fails to load, check these common issues:

• White Screen Crash: This is common on Steam Deck or specific monitors. It usually involves resolution conflicts. See our Steam Deck Configuration Guide for the WINEDLLOVERRIDES fix.
• “Failed to Load Assets”: This means the executable is 1.15, but you haven’t installed the 11GB asset pack correctly. Refer back to the main Installation Guide.
• Controller Not Working: The 1.15 executable sometimes struggles with Steam Input. Ensure you have “Forced Off” Steam Input in the game properties if your controller is unresponsive.

For a full list of error codes and fixes, visit the Troubleshooting Hub.

Frequently Asked Questions (FAQ)