Bump version to 2.3.8

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
v2.3.8: auto-update agent from GitHub releases, add dl1 mirror fallback
2026-02-26 10:31:47 -03:00 · 2026-02-21 23:47:52 +01:00 · 2026-02-21 23:31:28 +01:00 · 2026-02-21 13:21:19 +01:00 · 2026-02-20 23:10:13 +01:00 · 2026-02-20 20:22:57 +01:00
20 changed files with 1667 additions and 620 deletions
--- a/.github/CODE_OF_CONDUCT.md
+++ b/.github/CODE_OF_CONDUCT.md
@@ -36,7 +36,7 @@ This Code of Conduct applies within all community spaces, and also applies when

 ## Enforcement

-Instances of abusive, harassing, or otherwise unacceptable behavior may be reported to the community leaders responsible for enforcement at [Discord Server, message Founders/Devs](https://discord.gg/hf2pdc). All complaints will be reviewed and investigated promptly and fairly.
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported to the community leaders responsible for enforcement at [Discord Server, message Founders/Devs](https://discord.gg/Fhbb9Yk5WW). All complaints will be reviewed and investigated promptly and fairly.

 All community leaders are obligated to respect the privacy and security of the reporter of any incident.

--- a/.github/ISSUE_TEMPLATE/support_request.yml
+++ b/.github/ISSUE_TEMPLATE/support_request.yml
@@ -22,7 +22,7 @@ body:
      value: |
        If you need help or support with using the launcher, please fill out this support request.
        Provide as much detail as possible so we can assist you effectively.
-        **Need a quick assistance?** Please Open-A-Ticket in our [Discord Server](https://discord.gg/gME8rUy3MB)!
+        **Need a quick assistance?** Please Open-A-Ticket in our [Discord Server](https://discord.gg/Fhbb9Yk5WW)!

  - type: textarea
    id: question
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -6,201 +6,117 @@ on:
      - 'v*'
  workflow_dispatch:

+env:
+  # Domain for small API calls (goes through Cloudflare - fine for <100MB)
+  FORGEJO_API: https://git.sanhost.net/api/v1
+  # Direct upload URL (bypasses Cloudflare for large files) - set in repo secrets
+  FORGEJO_UPLOAD: ${{ secrets.FORGEJO_UPLOAD_URL }}
+
 jobs:
-  build-windows:
-    runs-on: windows-latest
+  create-release:
+    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
+      - name: Create Draft Release
+        run: |
+          curl -s -X POST "${FORGEJO_API}/repos/${GITHUB_REPOSITORY}/releases" \
+            -H "Authorization: token ${{ secrets.RELEASE_TOKEN }}" \
+            -H "Content-Type: application/json" \
+            -d "{\"tag_name\":\"${{ github.ref_name }}\",\"name\":\"${{ github.ref_name }}\",\"body\":\"Release ${{ github.ref_name }}\",\"draft\":true,\"prerelease\":false}" \
+            -o release.json
+          cat release.json
+          echo "RELEASE_ID=$(cat release.json | python3 -c 'import sys,json; print(json.load(sys.stdin)["id"])')" >> $GITHUB_ENV
+
+  build-windows:
+    needs: [create-release]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Wine for cross-compilation
+        run: |
+          sudo dpkg --add-architecture i386
+          sudo mkdir -pm755 /etc/apt/keyrings
+          sudo wget -O /etc/apt/keyrings/winehq-archive.key https://dl.winehq.org/wine-builds/winehq.key
+          sudo wget -NP /etc/apt/sources.list.d/ https://dl.winehq.org/wine-builds/ubuntu/dists/$(lsb_release -cs)/winehq-$(lsb_release -cs).sources
+          sudo apt-get update
+          sudo apt-get install -y --install-recommends winehq-stable
      - uses: actions/setup-node@v4
        with:
          node-version: '22'
-          cache: 'npm'
      - run: npm ci

-      - name: Create Virtual .env File
-        # Because main.js needed physical env, we need to create virtual one to store it
-        run: |
-          $env_content = @"
-          HF2P_PROXY_URL=${{ secrets.HF2P_PROXY_URL }}
-          HF2P_SECRET_KEY=${{ secrets.HF2P_SECRET_KEY }}
-          "@
-          Set-Content -Path .env -Value $env_content
-      
      - name: Build Windows Packages
-        run: npx electron-builder --win --publish never
-      - uses: actions/upload-artifact@v4
-        with:
-          name: windows-builds
-          path: |
-            dist/*.exe
-            dist/*.exe.blockmap
-            dist/latest.yml
+        run: npx electron-builder --win --publish never --config.npmRebuild=false
+
+      - name: Upload to Release
+        run: |
+          RELEASE_ID=$(curl -s "${FORGEJO_API}/repos/${GITHUB_REPOSITORY}/releases/tags/${{ github.ref_name }}" \
+            -H "Authorization: token ${{ secrets.RELEASE_TOKEN }}" | python3 -c 'import sys,json; print(json.load(sys.stdin)["id"])')
+          for file in dist/*.exe dist/*.exe.blockmap dist/latest.yml; do
+            [ -f "$file" ] || continue
+            echo "Uploading $file..."
+            curl -s --max-time 600 -X POST "${FORGEJO_UPLOAD}/repos/${GITHUB_REPOSITORY}/releases/${RELEASE_ID}/assets?name=$(basename $file)" \
+              -H "Authorization: token ${{ secrets.RELEASE_TOKEN }}" \
+              -F "attachment=@${file}" || echo "Failed to upload $file"
+          done

  build-macos:
+    needs: [create-release]
    runs-on: macos-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '22'
-          cache: 'npm'
      - run: npm ci

-      - name: Create Virtual .env File
-        run: |
-          cat << EOF > .env
-          HF2P_PROXY_URL=${{ secrets.HF2P_PROXY_URL }}
-          HF2P_SECRET_KEY=${{ secrets.HF2P_SECRET_KEY }}
-          EOF
-
      - name: Build macOS Packages
        env:
-          # Code signing
          CSC_LINK: ${{ secrets.CSC_LINK }}
          CSC_KEY_PASSWORD: ${{ secrets.CSC_KEY_PASSWORD }}
-          # Notarization
          APPLE_ID: ${{ secrets.APPLE_ID }}
          APPLE_APP_SPECIFIC_PASSWORD: ${{ secrets.APPLE_APP_SPECIFIC_PASSWORD }}
          APPLE_TEAM_ID: ${{ secrets.APPLE_TEAM_ID }}
        run: npx electron-builder --mac --publish never
-      - uses: actions/upload-artifact@v4
-        with:
-          name: macos-builds
-          path: |
-            dist/*.dmg
-            dist/*.zip
-            dist/*.blockmap
-            dist/latest-mac.yml
+
+      - name: Upload to Release
+        run: |
+          RELEASE_ID=$(curl -s "${FORGEJO_API}/repos/${GITHUB_REPOSITORY}/releases/tags/${{ github.ref_name }}" \
+            -H "Authorization: token ${{ secrets.RELEASE_TOKEN }}" | python3 -c 'import sys,json; print(json.load(sys.stdin)["id"])')
+          for file in dist/*.dmg dist/*.zip dist/*.blockmap dist/latest-mac.yml; do
+            [ -f "$file" ] || continue
+            echo "Uploading $file..."
+            curl -s --max-time 600 -X POST "${FORGEJO_UPLOAD}/repos/${GITHUB_REPOSITORY}/releases/${RELEASE_ID}/assets?name=$(basename $file)" \
+              -H "Authorization: token ${{ secrets.RELEASE_TOKEN }}" \
+              -F "attachment=@${file}" || echo "Failed to upload $file"
+          done

  build-linux:
    runs-on: ubuntu-latest
+    needs: [create-release]
    steps:
      - uses: actions/checkout@v4
      - name: Install build dependencies
        run: |
          sudo apt-get update
-          sudo apt-get install -y libarchive-tools
+          sudo apt-get install -y libarchive-tools rpm

      - uses: actions/setup-node@v4
        with:
          node-version: '22'
-          cache: 'npm'
      - run: npm ci

-      - name: Create Virtual .env File
-        run: |
-          cat << EOF > .env
-          HF2P_PROXY_URL=${{ secrets.HF2P_PROXY_URL }}
-          HF2P_SECRET_KEY=${{ secrets.HF2P_SECRET_KEY }}
-          EOF
-
      - name: Build Linux Packages
+        run: npx electron-builder --linux AppImage deb rpm pacman --publish never
+
+      - name: Upload to Release
        run: |
-          npx electron-builder --linux AppImage deb rpm --publish never
-      - uses: actions/upload-artifact@v4
-        with:
-          name: linux-builds
-          path: |
-            dist/*.AppImage
-            dist/*.AppImage.blockmap
-            dist/*.deb
-            dist/*.rpm
-            dist/latest-linux.yml
-
-  build-arch:
-    runs-on: ubuntu-latest
-    container:
-      image: archlinux:latest
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-          
-      - name: Install base packages
-        run: |
-          pacman -Syu --noconfirm
-          pacman -S --noconfirm \
-            base-devel \
-            git \
-            nodejs \
-            npm \
-            rpm-tools \
-            libxcrypt-compat
-
-      - name: Create build user
-        run: |
-          useradd -m builder
-          echo "builder ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
-
-      - name: Fix Permissions
-        run: chown -R builder:builder .
-
-      - name: Build Arch Package
-        run: |
-          sudo -u builder bash << 'EOF'
-          set -e
-          
-          cat << EOP > .env
-          HF2P_PROXY_URL=${{ secrets.HF2P_PROXY_URL }}
-          HF2P_SECRET_KEY=${{ secrets.HF2P_SECRET_KEY }}
-          EOP
-          
-          makepkg --printsrcinfo > .SRCINFO
-          makepkg -s --noconfirm
-          EOF
-
-      - name: Fix permissions for upload
-        if: always()
-        run: |
-          sudo chown -R $(id -u):$(id -g) .
-
-      - name: Upload Arch Package
-        uses: actions/upload-artifact@v4
-        with:
-          name: arch-package
-          path: |
-            *.pkg.tar.zst
-            .SRCINFO
-
-  release:
-    needs: [build-windows, build-macos, build-linux, build-arch]
-    runs-on: ubuntu-latest
-    if: |
-      startsWith(github.ref, 'refs/tags/v') || 
-      github.ref == 'refs/heads/main' || 
-      github.event_name == 'workflow_dispatch'
-
-    permissions:
-      contents: write
-
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: Download all artifacts
-        uses: actions/download-artifact@v4
-        with:
-          path: artifacts
-
-      - name: Display structure of downloaded files
-        run: ls -R artifacts
-
-      - name: Get version from package.json
-        id: pkg_version
-        run: echo "VERSION=$(node -p "require('./package.json').version")" >> $GITHUB_OUTPUT
-
-      - name: Create Release
-        uses: softprops/action-gh-release@v2
-        with:
-          tag_name: ${{ github.ref_name }}
-          files: |
-            artifacts/arch-package/*.pkg.tar.zst
-            artifacts/arch-package/.SRCINFO
-            artifacts/linux-builds/**/*
-            artifacts/windows-builds/**/*
-            artifacts/macos-builds/**/*
-          generate_release_notes: true
-          draft: true
-          prerelease: false
-          
+          RELEASE_ID=$(curl -s "${FORGEJO_API}/repos/${GITHUB_REPOSITORY}/releases/tags/${{ github.ref_name }}" \
+            -H "Authorization: token ${{ secrets.RELEASE_TOKEN }}" | python3 -c 'import sys,json; print(json.load(sys.stdin)["id"])')
+          for file in dist/*.AppImage dist/*.AppImage.blockmap dist/*.deb dist/*.rpm dist/*.pacman dist/latest-linux.yml; do
+            [ -f "$file" ] || continue
+            echo "Uploading $file..."
+            curl -s --max-time 600 -X POST "${FORGEJO_UPLOAD}/repos/${GITHUB_REPOSITORY}/releases/${RELEASE_ID}/assets?name=$(basename $file)" \
+              -H "Authorization: token ${{ secrets.RELEASE_TOKEN }}" \
+              -F "attachment=@${file}" || echo "Failed to upload $file"
+          done
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,9 @@ dist/
 # Project Specific: Downloaded patcher (from hytale-auth-server)
 backend/patcher/

+# Private docs (local only)
+docs/PATCH_CDN_INFRASTRUCTURE.md
+
 # macOS Specific
 .DS_Store
 *.zst.DS_Store
--- a/GUI/js/script.js
+++ b/GUI/js/script.js
@@ -53,7 +53,7 @@ window.closeDiscordPopup = function() {
 };

 window.joinDiscord = async function() {
-  await window.electronAPI?.openExternal('https://discord.gg/hf2pdc');
+  await window.electronAPI?.openExternal('https://discord.gg/Fhbb9Yk5WW');
  
  try {
    await window.electronAPI?.saveConfig({ discordPopup: true });
--- a/GUI/js/ui.js
+++ b/GUI/js/ui.js
@@ -1103,7 +1103,7 @@ function getRetryContextMessage() {
 }

 window.openDiscordExternal = function() {
-  window.electronAPI?.openExternal('https://discord.gg/hf2pdc');
+  window.electronAPI?.openExternal('https://discord.gg/Fhbb9Yk5WW');
 };

 window.toggleMaximize = toggleMaximize;
--- a/README.md
+++ b/README.md
@@ -18,7 +18,7 @@

 ### ⚠️ **WARNING: READ [QUICK START](#-quick-start) before Downloading & Installing the Launcher!** ⚠️

-#### 🛑 **Found a problem? [Join the HF2P Discord](https://discord.gg/hf2pdc) and head to `#-⚠️-community-help`** 🛑
+#### 🛑 **Found a problem? [Join the HF2P Discord](https://discord.gg/Fhbb9Yk5WW) and head to `#-⚠️-community-help`** 🛑

 <p>
  👍 If you like the project, <b>feel free to support us via Buy Me a Coffee!</b> ☕<br>
@@ -455,7 +455,7 @@ See [BUILD.md](docs/BUILD.md) for comprehensive build instructions.
 <div align="center">

 **Questions? Ads? Collaboration? Endorsement? Other business-related?** 
-Message the founders at https://discord.gg/hf2pdc
+Message the founders at https://discord.gg/Fhbb9Yk5WW

 </div>

--- a/SERVER.md
+++ b/SERVER.md
@@ -2,7 +2,7 @@

 Play with friends online! This guide covers both easy in-game hosting and advanced dedicated server setup.

-### **DOWNLOAD SERVER FILES (JAR/RAR/SCRIPTS) HERE: https://discord.gg/hf2pdc** 
+### **DOWNLOAD SERVER FILES (JAR/RAR/SCRIPTS) HERE: https://discord.gg/Fhbb9Yk5WW** 

 **Table of Contents**

--- a/TROUBLESHOOTING.md
+++ b/TROUBLESHOOTING.md
@@ -1,6 +1,6 @@
 # Hytale F2P Launcher - Troubleshooting Guide

-This guide covers common issues and their solutions. If your issue isn't listed here, please check [existing issues](https://github.com/amiayweb/Hytale-F2P/issues) or join our [Discord](https://discord.gg/gME8rUy3MB).
+This guide covers common issues and their solutions. If your issue isn't listed here, please check [existing issues](https://github.com/amiayweb/Hytale-F2P/issues) or join our [Discord](https://discord.gg/Fhbb9Yk5WW).

 ---

@@ -437,7 +437,7 @@ Game sessions have a 10-hour TTL. This is by design for security.
 If your issue isn't resolved by this guide:

 1. **Check existing issues:** [GitHub Issues](https://github.com/amiayweb/Hytale-F2P/issues)
-2. **Join Discord:** [discord.gg/gME8rUy3MB](https://discord.gg/gME8rUy3MB)
+2. **Join Discord:** [discord.gg/Fhbb9Yk5WW](https://discord.gg/Fhbb9Yk5WW)
 3. **Open a new issue** with:
   - Your operating system and version
   - Launcher version
--- a/backend/appUpdater.js
+++ b/backend/appUpdater.js
@@ -4,6 +4,10 @@ const logger = require('./logger');
 const fs = require('fs');
 const path = require('path');
 const os = require('os');
+const https = require('https');
+
+const FORGEJO_API = 'https://git.sanhost.net/api/v1';
+const FORGEJO_REPO = 'sanasol/hytale-f2p';

 class AppUpdater {
  constructor(mainWindow) {
@@ -14,6 +18,34 @@ class AppUpdater {
    this.setupAutoUpdater();
  }

+  /**
+   * Fetch the latest non-draft release tag from Forgejo and set the feed URL
+   */
+  async _resolveUpdateUrl() {
+    return new Promise((resolve, reject) => {
+      https.get(`${FORGEJO_API}/repos/${FORGEJO_REPO}/releases?limit=5`, (res) => {
+        let data = '';
+        res.on('data', (chunk) => data += chunk);
+        res.on('end', () => {
+          try {
+            const releases = JSON.parse(data);
+            const latest = releases.find(r => !r.draft && !r.prerelease);
+            if (latest) {
+              const url = `https://git.sanhost.net/${FORGEJO_REPO}/releases/download/${latest.tag_name}`;
+              console.log(`Auto-update URL resolved to: ${url}`);
+              autoUpdater.setFeedURL({ provider: 'generic', url });
+              resolve(url);
+            } else {
+              reject(new Error('No published release found'));
+            }
+          } catch (e) {
+            reject(e);
+          }
+        });
+      }).on('error', reject);
+    });
+  }
+
  setupAutoUpdater() {

    // Configure logger for electron-updater
@@ -216,8 +248,10 @@ class AppUpdater {
  }

  checkForUpdatesAndNotify() {
-    // Check for updates and notify if available
-    autoUpdater.checkForUpdatesAndNotify().catch(err => {
+    // Resolve latest release URL then check for updates
+    this._resolveUpdateUrl().catch(err => {
+      console.warn('Failed to resolve update URL:', err.message);
+    }).then(() => autoUpdater.checkForUpdatesAndNotify()).catch(err => {
      console.error('Failed to check for updates:', err);
      
      // Network errors are not critical - just log and continue
@@ -245,8 +279,10 @@ class AppUpdater {
  }

  checkForUpdates() {
-    // Manual check for updates (returns promise)
-    return autoUpdater.checkForUpdates().catch(err => {
+    // Manual check - resolve latest release URL first
+    return this._resolveUpdateUrl().catch(err => {
+      console.warn('Failed to resolve update URL:', err.message);
+    }).then(() => autoUpdater.checkForUpdates()).catch(err => {
      console.error('Failed to check for updates:', err);
      
      // Network errors are not critical - just return no update available
--- a/backend/core/config.js
+++ b/backend/core/config.js
@@ -54,6 +54,7 @@ function getAppDir() {
 const CONFIG_FILE = path.join(getAppDir(), 'config.json');
 const CONFIG_BACKUP = path.join(getAppDir(), 'config.json.bak');
 const CONFIG_TEMP = path.join(getAppDir(), 'config.json.tmp');
+const UUID_STORE_FILE = path.join(getAppDir(), 'uuid-store.json');

 // =============================================================================
 // CONFIG VALIDATION
@@ -152,6 +153,22 @@ function saveConfig(update) {

      // Load current config
      const currentConfig = loadConfig();
+
+      // SAFETY: If config file exists on disk but loadConfig() returned empty,
+      // something is wrong (file locked, corrupted, etc.). Refuse to save
+      // because merging with {} would wipe all existing data (userUuids, username, etc.)
+      if (Object.keys(currentConfig).length === 0 && fs.existsSync(CONFIG_FILE)) {
+        const fileSize = fs.statSync(CONFIG_FILE).size;
+        if (fileSize > 2) { // More than just "{}"
+          console.error(`[Config] REFUSING to save — loaded empty but file exists (${fileSize} bytes). Retrying load...`);
+          // Wait and retry the load
+          const delay = attempt * 200;
+          const start = Date.now();
+          while (Date.now() - start < delay) { /* busy wait */ }
+          continue;
+        }
+      }
+
      const newConfig = { ...currentConfig, ...update };
      const data = JSON.stringify(newConfig, null, 2);

@@ -238,11 +255,18 @@ function saveUsername(username) {
  // Check if we're actually changing the username (case-insensitive comparison)
  const isRename = currentName && currentName.toLowerCase() !== newName.toLowerCase();

+  // Also update UUID store (source of truth)
+  migrateUuidStoreIfNeeded();
+  const uuidStore = loadUuidStore();
+
  if (isRename) {
    // Find the UUID for the current username
    const currentKey = Object.keys(userUuids).find(
      k => k.toLowerCase() === currentName.toLowerCase()
    );
+    const currentStoreKey = Object.keys(uuidStore).find(
+      k => k.toLowerCase() === currentName.toLowerCase()
+    );

    if (currentKey && userUuids[currentKey]) {
      // Check if target username already exists (would be a different identity)
@@ -258,6 +282,9 @@ function saveUsername(username) {
        const uuid = userUuids[currentKey];
        delete userUuids[currentKey];
        userUuids[newName] = uuid;
+        // Same in UUID store
+        if (currentStoreKey) delete uuidStore[currentStoreKey];
+        uuidStore[newName] = uuid;
        console.log(`[Config] Renamed identity: "${currentKey}" → "${newName}" (UUID preserved: ${uuid})`);
      }
    }
@@ -270,11 +297,20 @@ function saveUsername(username) {
      const uuid = userUuids[currentKey];
      delete userUuids[currentKey];
      userUuids[newName] = uuid;
+      // Same in UUID store
+      const storeKey = Object.keys(uuidStore).find(k => k.toLowerCase() === currentName.toLowerCase());
+      if (storeKey) {
+        delete uuidStore[storeKey];
+        uuidStore[newName] = uuid;
+      }
      console.log(`[Config] Updated username case: "${currentKey}" → "${newName}"`);
    }
  }

-  // Save both username and updated userUuids
+  // Save UUID store
+  saveUuidStore(uuidStore);
+
+  // Save both username and updated userUuids to config
  saveConfig({ username: newName, userUuids });
  console.log(`[Config] Username saved: "${newName}"`);
  return newName;
@@ -310,6 +346,7 @@ function hasUsername() {

 // =============================================================================
 // UUID MANAGEMENT - Persistent and safe
+// Uses separate uuid-store.json as source of truth (survives config.json corruption)
 // =============================================================================

 /**
@@ -320,10 +357,55 @@ function normalizeUsername(username) {
  return username.trim().toLowerCase();
 }

+/**
+ * Load UUID store from separate file (independent of config.json)
+ */
+function loadUuidStore() {
+  try {
+    if (fs.existsSync(UUID_STORE_FILE)) {
+      const data = fs.readFileSync(UUID_STORE_FILE, 'utf8');
+      if (data.trim()) {
+        return JSON.parse(data);
+      }
+    }
+  } catch (err) {
+    console.error('[UUID Store] Failed to load:', err.message);
+  }
+  return {};
+}
+
+/**
+ * Save UUID store to separate file (atomic write)
+ */
+function saveUuidStore(store) {
+  try {
+    const dir = path.dirname(UUID_STORE_FILE);
+    if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
+    const tmpFile = UUID_STORE_FILE + '.tmp';
+    fs.writeFileSync(tmpFile, JSON.stringify(store, null, 2), 'utf8');
+    fs.renameSync(tmpFile, UUID_STORE_FILE);
+  } catch (err) {
+    console.error('[UUID Store] Failed to save:', err.message);
+  }
+}
+
+/**
+ * One-time migration: copy userUuids from config.json to uuid-store.json
+ */
+function migrateUuidStoreIfNeeded() {
+  if (fs.existsSync(UUID_STORE_FILE)) return; // Already migrated
+  const config = loadConfig();
+  if (config.userUuids && Object.keys(config.userUuids).length > 0) {
+    console.log('[UUID Store] Migrating', Object.keys(config.userUuids).length, 'UUIDs from config.json');
+    saveUuidStore(config.userUuids);
+  }
+}
+
 /**
 * Get UUID for a username
- * Creates new UUID only if user explicitly doesn't exist
- * Uses case-insensitive lookup to prevent duplicates, but preserves original case for display
+ * Source of truth: uuid-store.json (separate from config.json)
+ * Also writes to config.json for backward compatibility
+ * Creates new UUID only if user doesn't exist in EITHER store
 */
 function getUuidForUser(username) {
  const { v4: uuidv4 } = require('uuid');
@@ -335,32 +417,69 @@ function getUuidForUser(username) {
  const displayName = username.trim();
  const normalizedLookup = displayName.toLowerCase();

-  const config = loadConfig();
-  const userUuids = config.userUuids || {};
+  // Ensure UUID store exists (one-time migration from config.json)
+  migrateUuidStoreIfNeeded();

-  // Case-insensitive lookup - find existing key regardless of case
-  const existingKey = Object.keys(userUuids).find(k => k.toLowerCase() === normalizedLookup);
+  // 1. Check UUID store first (source of truth)
+  const uuidStore = loadUuidStore();
+  const storeKey = Object.keys(uuidStore).find(k => k.toLowerCase() === normalizedLookup);

-  if (existingKey) {
-    // Found existing - return UUID, update display name if case changed
-    const existingUuid = userUuids[existingKey];
+  if (storeKey) {
+    const existingUuid = uuidStore[storeKey];

-    // If user typed different case, update the key to new case (preserving UUID)
-    if (existingKey !== displayName) {
-      console.log(`[Config] Updating username case: "${existingKey}" → "${displayName}"`);
-      delete userUuids[existingKey];
-      userUuids[displayName] = existingUuid;
-      saveConfig({ userUuids });
+    // Update case if needed
+    if (storeKey !== displayName) {
+      console.log(`[UUID Store] Updating username case: "${storeKey}" → "${displayName}"`);
+      delete uuidStore[storeKey];
+      uuidStore[displayName] = existingUuid;
+      saveUuidStore(uuidStore);
    }

+    // Sync to config.json (backward compat, non-critical)
+    try {
+      const config = loadConfig();
+      const configUuids = config.userUuids || {};
+      const configKey = Object.keys(configUuids).find(k => k.toLowerCase() === normalizedLookup);
+      if (!configKey || configUuids[configKey] !== existingUuid) {
+        if (configKey) delete configUuids[configKey];
+        configUuids[displayName] = existingUuid;
+        saveConfig({ userUuids: configUuids });
+      }
+    } catch (e) {
+      // Non-critical — UUID store is the source of truth
+    }
+
+    console.log(`[UUID] ${displayName} → ${existingUuid} (from uuid-store)`);
    return existingUuid;
  }

-  // Create new UUID for new user - store with original case
+  // 2. Fallback: check config.json (recovery if uuid-store.json was lost)
+  const config = loadConfig();
+  const userUuids = config.userUuids || {};
+  const configKey = Object.keys(userUuids).find(k => k.toLowerCase() === normalizedLookup);
+
+  if (configKey) {
+    const recoveredUuid = userUuids[configKey];
+    console.warn(`[UUID] RECOVERED "${displayName}" → ${recoveredUuid} from config.json (uuid-store was missing)`);
+
+    // Save to UUID store
+    uuidStore[displayName] = recoveredUuid;
+    saveUuidStore(uuidStore);
+
+    return recoveredUuid;
+  }
+
+  // 3. New user — generate UUID, save to BOTH stores
  const newUuid = uuidv4();
+  console.log(`[UUID] NEW user "${displayName}" → ${newUuid}`);
+
+  // Save to UUID store (source of truth)
+  uuidStore[displayName] = newUuid;
+  saveUuidStore(uuidStore);
+
+  // Save to config.json (backward compat)
  userUuids[displayName] = newUuid;
  saveConfig({ userUuids });
-  console.log(`[Config] Created new UUID for "${displayName}": ${newUuid}`);

  return newUuid;
 }
@@ -380,22 +499,26 @@ function getCurrentUuid() {
 * Get all UUID mappings (raw object)
 */
 function getAllUuidMappings() {
+  migrateUuidStoreIfNeeded();
+  const uuidStore = loadUuidStore();
+  // Fallback to config if uuid-store is empty
+  if (Object.keys(uuidStore).length === 0) {
    const config = loadConfig();
    return config.userUuids || {};
  }
+  return uuidStore;
+}

 /**
 * Get all UUID mappings as array with current user flag
 */
 function getAllUuidMappingsArray() {
-  const config = loadConfig();
-  const userUuids = config.userUuids || {};
+  const allMappings = getAllUuidMappings();
  const currentUsername = loadUsername();
-  // Case-insensitive comparison for isCurrent
  const normalizedCurrent = currentUsername ? currentUsername.toLowerCase() : null;

-  return Object.entries(userUuids).map(([username, uuid]) => ({
-    username,  // Original case preserved
+  return Object.entries(allMappings).map(([username, uuid]) => ({
+    username,
    uuid,
    isCurrent: username.toLowerCase() === normalizedCurrent
  }));
@@ -419,16 +542,20 @@ function setUuidForUser(username, uuid) {

  const displayName = username.trim();
  const normalizedLookup = displayName.toLowerCase();
+
+  // 1. Update UUID store (source of truth)
+  migrateUuidStoreIfNeeded();
+  const uuidStore = loadUuidStore();
+  const storeKey = Object.keys(uuidStore).find(k => k.toLowerCase() === normalizedLookup);
+  if (storeKey) delete uuidStore[storeKey];
+  uuidStore[displayName] = uuid;
+  saveUuidStore(uuidStore);
+
+  // 2. Update config.json (backward compat)
  const config = loadConfig();
  const userUuids = config.userUuids || {};
-
-  // Remove any existing entry with same name (case-insensitive)
  const existingKey = Object.keys(userUuids).find(k => k.toLowerCase() === normalizedLookup);
-  if (existingKey) {
-    delete userUuids[existingKey];
-  }
-
-  // Store with original case
+  if (existingKey) delete userUuids[existingKey];
  userUuids[displayName] = uuid;
  saveConfig({ userUuids });

@@ -454,20 +581,30 @@ function deleteUuidForUser(username) {
  }

  const normalizedLookup = username.trim().toLowerCase();
+  let deleted = false;
+
+  // 1. Delete from UUID store (source of truth)
+  migrateUuidStoreIfNeeded();
+  const uuidStore = loadUuidStore();
+  const storeKey = Object.keys(uuidStore).find(k => k.toLowerCase() === normalizedLookup);
+  if (storeKey) {
+    delete uuidStore[storeKey];
+    saveUuidStore(uuidStore);
+    deleted = true;
+  }
+
+  // 2. Delete from config.json (backward compat)
  const config = loadConfig();
  const userUuids = config.userUuids || {};
-
-  // Case-insensitive lookup
  const existingKey = Object.keys(userUuids).find(k => k.toLowerCase() === normalizedLookup);
-
  if (existingKey) {
    delete userUuids[existingKey];
    saveConfig({ userUuids });
-    console.log(`[Config] UUID deleted for "${username}"`);
-    return true;
+    deleted = true;
  }

-  return false;
+  if (deleted) console.log(`[Config] UUID deleted for "${username}"`);
+  return deleted;
 }

 /**
@@ -788,5 +925,6 @@ module.exports = {
  loadVersionBranch,

  // Constants
-  CONFIG_FILE
+  CONFIG_FILE,
+  UUID_STORE_FILE
 };
--- a/backend/managers/differentialUpdateManager.js
+++ b/backend/managers/differentialUpdateManager.js
@@ -3,7 +3,7 @@ const path = require('path');
 const { execFile } = require('child_process');
 const { downloadFile, retryDownload } = require('../utils/fileManager');
 const { getOS, getArch } = require('../utils/platformUtils');
-const { validateChecksum, extractVersionDetails, canUseDifferentialUpdate, needsIntermediatePatches, getInstalledClientVersion } = require('../services/versionManager');
+const { validateChecksum, extractVersionDetails, getInstalledClientVersion, getUpdatePlan, extractVersionNumber, getAllMirrorUrls, getPatchesBaseUrl } = require('../services/versionManager');
 const { installButler } = require('./butlerManager');
 const { GAME_DIR, CACHE_DIR, TOOLS_DIR } = require('../core/paths');
 const { saveVersionClient } = require('../core/config');
@@ -31,15 +31,62 @@ async function acquireGameArchive(downloadUrl, targetPath, checksum, progressCal

  console.log(`Downloading game archive from: ${downloadUrl}`);

-  try {
-    if (allowRetry) {
-      await retryDownload(downloadUrl, targetPath, progressCallback);
-    } else {
-      await downloadFile(downloadUrl, targetPath, progressCallback);
+  // Try primary URL first, then mirror URLs on timeout/connection failure
+  const mirrors = await getAllMirrorUrls();
+  const primaryBase = await getPatchesBaseUrl();
+  const urlsToTry = [downloadUrl];
+
+  // Build mirror URLs by replacing the base URL
+  for (const mirror of mirrors) {
+    if (mirror !== primaryBase && downloadUrl.startsWith(primaryBase)) {
+      const mirrorUrl = downloadUrl.replace(primaryBase, mirror);
+      if (!urlsToTry.includes(mirrorUrl)) {
+        urlsToTry.push(mirrorUrl);
      }
+    }
+  }
+
+  let lastError;
+  for (let i = 0; i < urlsToTry.length; i++) {
+    const url = urlsToTry[i];
+    try {
+      if (i > 0) {
+        console.log(`[Download] Trying mirror ${i}: ${url}`);
+        if (progressCallback) {
+          progressCallback(`Trying alternative mirror (${i}/${urlsToTry.length - 1})...`, 0, null, null, null);
+        }
+        // Clean up partial download from previous attempt
+        if (fs.existsSync(targetPath)) {
+          try { fs.unlinkSync(targetPath); } catch (e) {}
+        }
+      }
+      if (allowRetry) {
+        await retryDownload(url, targetPath, progressCallback);
+      } else {
+        await downloadFile(url, targetPath, progressCallback);
+      }
+      lastError = null;
+      break; // Success
    } catch (error) {
-    const enhancedError = new Error(`Archive download failed: ${error.message}`);
-    enhancedError.originalError = error;
+      lastError = error;
+      const isConnectionError = error.message && (
+        error.message.includes('ETIMEDOUT') ||
+        error.message.includes('ECONNREFUSED') ||
+        error.message.includes('ECONNABORTED') ||
+        error.message.includes('timeout')
+      );
+      if (isConnectionError && i < urlsToTry.length - 1) {
+        console.warn(`[Download] Connection failed (${error.message}), will try mirror...`);
+        continue;
+      }
+      // Non-connection error or last mirror — throw
+      break;
+    }
+  }
+
+  if (lastError) {
+    const enhancedError = new Error(`Archive download failed: ${lastError.message}`);
+    enhancedError.originalError = lastError;
    enhancedError.downloadUrl = downloadUrl;
    enhancedError.targetPath = targetPath;
    throw enhancedError;
@@ -156,15 +203,15 @@ async function performIntelligentUpdate(targetVersion, branch = 'release', progr
  console.log(`Initiating intelligent update to version ${targetVersion}`);

  const currentVersion = getInstalledClientVersion();
-  console.log(`Current version: ${currentVersion || 'none (clean install)'}`);
-  console.log(`Target version: ${targetVersion}`);
-  console.log(`Branch: ${branch}`);
+  const currentBuild = extractVersionNumber(currentVersion) || 0;
+  const targetBuild = extractVersionNumber(targetVersion);
+  console.log(`Current build: ${currentBuild}, Target build: ${targetBuild}, Branch: ${branch}`);

+  // For non-release branches, always do full install
  if (branch !== 'release') {
-    console.log(`Pre-release branch detected - forcing full archive download`);
+    console.log('Pre-release branch detected - forcing full archive download');
    const versionDetails = await extractVersionDetails(targetVersion, branch);
-    const archiveName = path.basename(versionDetails.fullUrl);
-    const archivePath = path.join(cacheDir, `${branch}_${archiveName}`);
+    const archivePath = path.join(cacheDir, `${branch}_0_to_${targetBuild}.pwr`);

    if (progressCallback) {
      progressCallback('Downloading full game archive (pre-release)...', 0, null, null, null);
@@ -177,14 +224,14 @@ async function performIntelligentUpdate(targetVersion, branch = 'release', progr
    return;
  }

-  if (!currentVersion) {
+  // Clean install (no current version)
+  if (currentBuild === 0) {
    console.log('No existing installation detected - downloading full archive');
    const versionDetails = await extractVersionDetails(targetVersion, branch);
-    const archiveName = path.basename(versionDetails.fullUrl);
-    const archivePath = path.join(cacheDir, `${branch}_${archiveName}`);
+    const archivePath = path.join(cacheDir, `${branch}_0_to_${targetBuild}.pwr`);

    if (progressCallback) {
-      progressCallback(`Downloading full game archive (first install - v${targetVersion})...`, 0, null, null, null);
+      progressCallback(`Downloading full game archive (first install - v${targetBuild})...`, 0, null, null, null);
    }

    await acquireGameArchive(versionDetails.fullUrl, archivePath, null, progressCallback);
@@ -194,59 +241,67 @@ async function performIntelligentUpdate(targetVersion, branch = 'release', progr
    return;
  }

-  const patchesToApply = needsIntermediatePatches(currentVersion, targetVersion);
-  
-  if (patchesToApply.length === 0) {
-    console.log('Already at target version or invalid version sequence');
+  // Already at target
+  if (currentBuild >= targetBuild) {
+    console.log('Already at target version or newer');
    return;
  }

-  console.log(`Applying ${patchesToApply.length} differential patch(es): ${patchesToApply.join(' -> ')}`);
+  // Use mirror's update plan for optimal patch routing
+  try {
+    const plan = await getUpdatePlan(currentBuild, targetBuild, branch);

-  for (let i = 0; i < patchesToApply.length; i++) {
-    const patchVersion = patchesToApply[i];
-    const versionDetails = await extractVersionDetails(patchVersion, branch);
+    console.log(`Applying ${plan.steps.length} patch(es): ${plan.steps.map(s => `${s.from}\u2192${s.to}`).join(' + ')}`);

-    const canDifferential = canUseDifferentialUpdate(getInstalledClientVersion(), versionDetails);
-    
-    if (!canDifferential || !versionDetails.differentialUrl) {
-      console.log(`WARNING: Differential patch not available for ${patchVersion}, using full archive`);
-      const archiveName = path.basename(versionDetails.fullUrl);
-      const archivePath = path.join(cacheDir, `${branch}_${archiveName}`);
+    for (let i = 0; i < plan.steps.length; i++) {
+      const step = plan.steps[i];
+      const stepName = `${step.from}_to_${step.to}`;
+      const archivePath = path.join(cacheDir, `${branch}_${stepName}.pwr`);
+      const isDifferential = step.from !== 0;

      if (progressCallback) {
-        progressCallback(`Downloading full archive for ${patchVersion} (${i + 1}/${patchesToApply.length})...`, 0, null, null, null);
+        progressCallback(`Downloading patch ${i + 1}/${plan.steps.length}: ${stepName}...`, 0, null, null, null);
+      }
+
+      await acquireGameArchive(step.url, archivePath, null, progressCallback);
+
+      if (progressCallback) {
+        progressCallback(`Applying patch ${i + 1}/${plan.steps.length}: ${stepName}...`, 50, null, null, null);
+      }
+
+      await deployGameArchive(archivePath, gameDir, toolsDir, progressCallback, isDifferential);
+
+      // Clean up patch file
+      if (fs.existsSync(archivePath)) {
+        try {
+          fs.unlinkSync(archivePath);
+          console.log(`Cleaned up: ${stepName}.pwr`);
+        } catch (cleanupErr) {
+          console.warn(`Failed to cleanup: ${cleanupErr.message}`);
+        }
+      }
+
+      saveVersionClient(`v${step.to}`);
+      console.log(`Patch ${stepName} applied (${i + 1}/${plan.steps.length})`);
+    }
+
+    console.log(`Update completed. Version ${targetVersion} is now installed.`);
+  } catch (planError) {
+    console.error('Update plan failed:', planError.message);
+    console.log('Falling back to full archive download');
+
+    // Fallback: full install
+    const versionDetails = await extractVersionDetails(targetVersion, branch);
+    const archivePath = path.join(cacheDir, `${branch}_0_to_${targetBuild}.pwr`);
+
+    if (progressCallback) {
+      progressCallback(`Downloading full game archive (fallback)...`, 0, null, null, null);
    }

    await acquireGameArchive(versionDetails.fullUrl, archivePath, null, progressCallback);
    await deployGameArchive(archivePath, gameDir, toolsDir, progressCallback, false);
-    } else {
-      console.log(`Applying differential patch: ${versionDetails.sourceVersion} -> ${patchVersion}`);
-      const archiveName = path.basename(versionDetails.differentialUrl);
-      const archivePath = path.join(cacheDir, `${branch}_patch_${archiveName}`);
-      
-      if (progressCallback) {
-        progressCallback(`Applying patch ${i + 1}/${patchesToApply.length}: ${patchVersion}...`, 0, null, null, null);
+    saveVersionClient(targetVersion);
  }
-      
-      await acquireGameArchive(versionDetails.differentialUrl, archivePath, versionDetails.checksum, progressCallback);
-      await deployGameArchive(archivePath, gameDir, toolsDir, progressCallback, true);
-      
-      if (fs.existsSync(archivePath)) {
-        try {
-          fs.unlinkSync(archivePath);
-          console.log(`Cleaned up patch file: ${archiveName}`);
-        } catch (cleanupErr) {
-          console.warn(`Failed to cleanup patch file: ${cleanupErr.message}`);
-        }
-      }
-    }
-    
-    saveVersionClient(patchVersion);
-    console.log(`Patch ${patchVersion} applied successfully (${i + 1}/${patchesToApply.length})`);
-  }
-
-  console.log(`Update completed successfully. Version ${targetVersion} is now installed.`);
 }

 async function ensureGameInstalled(targetVersion, branch = 'release', progressCallback, gameDir = GAME_DIR, cacheDir = CACHE_DIR, toolsDir = TOOLS_DIR) {
--- a/backend/managers/gameLauncher.js
+++ b/backend/managers/gameLauncher.js
@@ -61,12 +61,39 @@ async function fetchAuthTokens(uuid, name) {
    }

    const data = await response.json();
-    console.log('Auth tokens received from server');
+    const identityToken = data.IdentityToken || data.identityToken;
+    const sessionToken = data.SessionToken || data.sessionToken;

+    // Verify the identity token has the correct username
+    // This catches cases where the auth server defaults to "Player"
+    try {
+      const parts = identityToken.split('.');
+      if (parts.length >= 2) {
+        const payload = JSON.parse(Buffer.from(parts[1], 'base64url').toString());
+        if (payload.username && payload.username !== name && name !== 'Player') {
+          console.warn(`[Auth] Token username mismatch: token has "${payload.username}", expected "${name}". Retrying...`);
+          // Retry once with explicit name
+          const retryResponse = await fetch(`${authServerUrl}/game-session/child`, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ uuid: uuid, name: name, scopes: ['hytale:server', 'hytale:client'] })
+          });
+          if (retryResponse.ok) {
+            const retryData = await retryResponse.json();
+            console.log('[Auth] Retry successful');
            return {
-      identityToken: data.IdentityToken || data.identityToken,
-      sessionToken: data.SessionToken || data.sessionToken
+              identityToken: retryData.IdentityToken || retryData.identityToken,
+              sessionToken: retryData.SessionToken || retryData.sessionToken
            };
+          }
+        }
+      }
+    } catch (verifyErr) {
+      console.warn('[Auth] Token verification skipped:', verifyErr.message);
+    }
+
+    console.log('Auth tokens received from server');
+    return { identityToken, sessionToken };
  } catch (error) {
    console.error('Failed to fetch auth tokens:', error.message);
    // Fallback to local generation if server unavailable
@@ -223,6 +250,7 @@ async function launchGame(playerNameOverride = null, progressCallback, javaPathO
  }

  const uuid = getUuidForUser(playerName);
+  console.log(`[Launcher] UUID for "${playerName}": ${uuid} (verify this stays constant across launches)`);

  // Fetch tokens from auth server
  if (progressCallback) {
@@ -412,7 +440,7 @@ exec "$REAL_JAVA" "\${ARGS[@]}"
  // This enables runtime auth patching without modifying the server JAR
  const agentJar = path.join(gameLatest, 'Server', 'dualauth-agent.jar');
  if (fs.existsSync(agentJar)) {
-    const agentFlag = `-javaagent:${agentJar}`;
+    const agentFlag = `-javaagent:"${agentJar}"`;
    env.JAVA_TOOL_OPTIONS = env.JAVA_TOOL_OPTIONS
      ? `${env.JAVA_TOOL_OPTIONS} ${agentFlag}`
      : agentFlag;
--- a/backend/managers/gameManager.js
+++ b/backend/managers/gameManager.js
@@ -5,7 +5,7 @@ const { promisify } = require('util');
 const { getResolvedAppDir, findClientPath, findUserDataPath, findUserDataRecursive, GAME_DIR, CACHE_DIR, TOOLS_DIR } = require('../core/paths');
 const { getOS, getArch } = require('../utils/platformUtils');
 const { downloadFile, retryDownload, retryStalledDownload, MAX_AUTOMATIC_STALL_RETRIES } = require('../utils/fileManager');
-const { getLatestClientVersion, getInstalledClientVersion } = require('../services/versionManager');
+const { getLatestClientVersion, getInstalledClientVersion, getUpdatePlan, extractVersionNumber } = require('../services/versionManager');
 const { FORCE_CLEAN_INSTALL_VERSION, CLEAN_INSTALL_TEST_VERSION } = require('../core/testConfig');
 const { installButler } = require('./butlerManager');
 const { downloadAndReplaceHomePageUI, downloadAndReplaceLogo } = require('./uiFileManager');
@@ -64,7 +64,7 @@ async function safeRemoveDirectory(dirPath, maxRetries = 3) {
  }
 }

-async function downloadPWR(branch = 'release', fileName = 'v8', progressCallback, cacheDir = CACHE_DIR, manualRetry = false) {
+async function downloadPWR(branch = 'release', fileName = 'v8', progressCallback, cacheDir = CACHE_DIR, manualRetry = false, directUrl = null, expectedSize = null) {
  const osName = getOS();
  const arch = getArch();

@@ -72,43 +72,69 @@ async function downloadPWR(branch = 'release', fileName = 'v8', progressCallback
    throw new Error('Hytale x86_64 Intel Mac Support has not been released yet. Please check back later.');
  }

-  const { getPWRUrlFromNewAPI } = require('../services/versionManager');
-  
  let url;
-  let isUsingNewAPI = false;

+  if (directUrl) {
+    url = directUrl;
+    console.log(`[DownloadPWR] Using direct URL: ${url}`);
+  } else {
+    const { getPWRUrl } = require('../services/versionManager');
    try {
-    console.log(`[DownloadPWR] Fetching URL from new API for branch: ${branch}, version: ${fileName}`);
-    url = await getPWRUrlFromNewAPI(branch, fileName);
-    isUsingNewAPI = true;
-    console.log(`[DownloadPWR] Using new API URL: ${url}`);
+      console.log(`[DownloadPWR] Fetching mirror URL for branch: ${branch}, version: ${fileName}`);
+      url = await getPWRUrl(branch, fileName);
+      console.log(`[DownloadPWR] Mirror URL: ${url}`);
    } catch (error) {
-    console.error(`[DownloadPWR] Failed to get URL from new API: ${error.message}`);
-    console.log(`[DownloadPWR] Falling back to old URL format`);
-    url = `https://game-patches.hytale.com/patches/${osName}/${arch}/${branch}/0/${fileName}.pwr`;
+      console.error(`[DownloadPWR] Failed to get mirror URL: ${error.message}`);
+      const { getPatchesBaseUrl } = require('../services/versionManager');
+      const baseUrl = await getPatchesBaseUrl();
+      url = `${baseUrl}/${osName}/${arch}/${branch}/0_to_${extractVersionNumber(fileName)}.pwr`;
+      console.log(`[DownloadPWR] Fallback URL: ${url}`);
+    }
+  }
+
+  // Look up expected file size from manifest if not provided
+  if (!expectedSize) {
+    try {
+      const { fetchMirrorManifest } = require('../services/versionManager');
+      const manifest = await fetchMirrorManifest();
+      // Try to match: "0_to_11" format or "v11" format
+      const versionMatch = fileName.match(/^(\d+)_to_(\d+)$/);
+      let manifestKey;
+      if (versionMatch) {
+        manifestKey = `${osName}/${arch}/${branch}/${fileName}.pwr`;
+      } else {
+        const buildNum = extractVersionNumber(fileName);
+        manifestKey = `${osName}/${arch}/${branch}/0_to_${buildNum}.pwr`;
+      }
+      if (manifest.files[manifestKey]) {
+        expectedSize = manifest.files[manifestKey].size;
+        console.log(`[PWR] Expected size from manifest: ${(expectedSize / 1024 / 1024).toFixed(2)} MB`);
+      }
+    } catch (e) {
+      console.log(`[PWR] Could not fetch expected size from manifest: ${e.message}`);
+    }
  }

  const dest = path.join(cacheDir, `${branch}_${fileName}.pwr`);

  // Check if file exists and validate it
  if (fs.existsSync(dest) && !manualRetry) {
-    console.log('PWR file found in cache:', dest);
-    
-    // Validate file size (PWR files should be > 1MB and >= 1.5GB for complete downloads)
    const stats = fs.statSync(dest);
-    if (stats.size < 1024 * 1024) {
-      return false;
+    if (stats.size > 1024 * 1024) {
+      // Validate against expected size - reject if file is truncated (< 99% of expected)
+      if (expectedSize && stats.size < expectedSize * 0.99) {
+        console.log(`[PWR] Cached file truncated: ${(stats.size / 1024 / 1024).toFixed(2)} MB, expected ${(expectedSize / 1024 / 1024).toFixed(2)} MB. Deleting and re-downloading.`);
+        fs.unlinkSync(dest);
+      } else {
+        console.log(`[PWR] Using cached file: ${dest} (${(stats.size / 1024 / 1024).toFixed(2)} MB)`);
+        return dest;
      }
-    
-    // Check if file is under 1.5 GB (incomplete download)
-    const sizeInMB = stats.size / 1024 / 1024;
-    if (sizeInMB < 1500) {
-      console.log(`[PWR Validation] File appears incomplete: ${sizeInMB.toFixed(2)} MB < 1.5 GB`);
-      return false;
+    } else {
+      console.log(`[PWR] Cached file too small (${stats.size} bytes), re-downloading`);
    }
  }

-  console.log(`Fetching PWR patch file from ${isUsingNewAPI ? 'NEW API' : 'old API'}:`, url);
+  console.log(`[DownloadPWR] Downloading from: ${url}`);
  
  try {
    if (manualRetry) {
@@ -134,7 +160,7 @@ async function downloadPWR(branch = 'release', fileName = 'v8', progressCallback
        const retryStats = fs.statSync(dest);
        console.log(`PWR file downloaded (auto-retry), size: ${(retryStats.size / 1024 / 1024).toFixed(2)} MB`);
        
-        if (!validatePWRFile(dest)) {
+        if (!validatePWRFile(dest, expectedSize)) {
          console.log(`[PWR Validation] PWR file validation failed after auto-retry, deleting corrupted file: ${dest}`);
          fs.unlinkSync(dest);
          throw new Error('Downloaded PWR file is corrupted or invalid after automatic retry. Please retry manually');
@@ -185,7 +211,7 @@ async function downloadPWR(branch = 'release', fileName = 'v8', progressCallback
  const stats = fs.statSync(dest);
  console.log(`PWR file downloaded, size: ${(stats.size / 1024 / 1024).toFixed(2)} MB`);

-  if (!validatePWRFile(dest)) {
+  if (!validatePWRFile(dest, expectedSize)) {
    console.log(`[PWR Validation] PWR file validation failed, deleting corrupted file: ${dest}`);
    fs.unlinkSync(dest);
    throw new Error('Downloaded PWR file is corrupted or invalid. Please retry');
@@ -203,7 +229,7 @@ async function retryPWRDownload(branch, fileName, progressCallback, cacheDir = C
  return await downloadPWR(branch, fileName, progressCallback, cacheDir, true);
 }

-async function applyPWR(pwrFile, progressCallback, gameDir = GAME_DIR, toolsDir = TOOLS_DIR, branch = 'release', cacheDir = CACHE_DIR) {
+async function applyPWR(pwrFile, progressCallback, gameDir = GAME_DIR, toolsDir = TOOLS_DIR, branch = 'release', cacheDir = CACHE_DIR, skipExistingCheck = false) {
  console.log(`[Butler] Starting PWR application with:`);
  console.log(`[Butler] - PWR file: ${pwrFile}`);
  console.log(`[Butler] - Staging dir: ${path.join(gameDir, 'staging-temp')}`);
@@ -227,12 +253,13 @@ async function applyPWR(pwrFile, progressCallback, gameDir = GAME_DIR, toolsDir
  const gameLatest = gameDir;
  const stagingDir = path.join(gameLatest, 'staging-temp');

+  if (!skipExistingCheck) {
    const clientPath = findClientPath(gameLatest);
-
    if (clientPath) {
      console.log('Game files detected, skipping patch installation.');
      return;
    }
+  }

  // Validate and prepare directories
  validateGameDirectory(gameLatest, stagingDir);
@@ -412,6 +439,65 @@ async function updateGameFiles(newVersion, progressCallback, gameDir = GAME_DIR,
    }
    console.log(`Updating game files to version: ${newVersion} (branch: ${branch})`);

+    // Determine update strategy: intermediate patches vs full reinstall
+    const currentVersion = loadVersionClient();
+    const currentBuild = extractVersionNumber(currentVersion) || 0;
+    const targetBuild = extractVersionNumber(newVersion);
+
+    let useIntermediatePatches = false;
+    let updatePlan = null;
+
+    if (currentBuild > 0 && currentBuild < targetBuild) {
+      try {
+        updatePlan = await getUpdatePlan(currentBuild, targetBuild, branch);
+        useIntermediatePatches = !updatePlan.isFullInstall;
+        if (useIntermediatePatches) {
+          const totalMB = (updatePlan.totalSize / 1024 / 1024).toFixed(0);
+          console.log(`[UpdateGameFiles] Using intermediate patches: ${updatePlan.steps.map(s => `${s.from}\u2192${s.to}`).join(' + ')} (${totalMB} MB)`);
+        }
+      } catch (planError) {
+        console.warn('[UpdateGameFiles] Could not get update plan, falling back to full install:', planError.message);
+      }
+    }
+
+    if (useIntermediatePatches && updatePlan) {
+      // Apply intermediate patches directly to game dir
+      for (let i = 0; i < updatePlan.steps.length; i++) {
+        const step = updatePlan.steps[i];
+        const stepName = `${step.from}_to_${step.to}`;
+
+        if (progressCallback) {
+          const progress = 20 + Math.round((i / updatePlan.steps.length) * 60);
+          progressCallback(`Downloading patch ${i + 1}/${updatePlan.steps.length} (${stepName})...`, progress, null, null, null);
+        }
+
+        const pwrFile = await downloadPWR(branch, stepName, progressCallback, cacheDir, false, step.url, step.size);
+
+        if (!pwrFile) {
+          throw new Error(`Failed to download patch ${stepName}`);
+        }
+
+        if (progressCallback) {
+          progressCallback(`Applying patch ${i + 1}/${updatePlan.steps.length} (${stepName})...`, null, null, null, null);
+        }
+
+        await applyPWR(pwrFile, progressCallback, gameDir, toolsDir, branch, cacheDir, true);
+
+        // Clean up PWR file from cache
+        try {
+          if (fs.existsSync(pwrFile)) {
+            fs.unlinkSync(pwrFile);
+          }
+        } catch (delErr) {
+          console.warn('[UpdateGameFiles] Failed to delete PWR from cache:', delErr.message);
+        }
+
+        // Save intermediate version so we can resume if interrupted
+        saveVersionClient(`v${step.to}`);
+        console.log(`[UpdateGameFiles] Applied patch ${stepName} (${i + 1}/${updatePlan.steps.length})`);
+      }
+    } else {
+      // Full install: download 0->target, apply to temp dir, swap
      tempUpdateDir = path.join(gameDir, '..', 'temp_update');

      if (fs.existsSync(tempUpdateDir)) {
@@ -430,7 +516,7 @@ async function updateGameFiles(newVersion, progressCallback, gameDir = GAME_DIR,
      }

      await applyPWR(pwrFile, progressCallback, tempUpdateDir, toolsDir, branch, cacheDir);
-    // Delete PWR file from cache after successful update
+
      try {
        if (fs.existsSync(pwrFile)) {
          fs.unlinkSync(pwrFile);
@@ -439,6 +525,7 @@ async function updateGameFiles(newVersion, progressCallback, gameDir = GAME_DIR,
      } catch (delErr) {
        console.warn('[UpdateGameFiles] Failed to delete PWR file from cache:', delErr.message);
      }
+
      if (progressCallback) {
        progressCallback('Replacing game files...', 80, null, null, null);
      }
@@ -463,6 +550,7 @@ async function updateGameFiles(newVersion, progressCallback, gameDir = GAME_DIR,
      }

      fs.renameSync(tempUpdateDir, gameDir);
+    }

    const homeUIResult = await downloadAndReplaceHomePageUI(gameDir, progressCallback);
    console.log('HomePage.ui update result after update:', homeUIResult);
@@ -833,7 +921,8 @@ function validateGameDirectory(gameDir, stagingDir) {
 }

 // Enhanced PWR file validation
-function validatePWRFile(filePath) {
+// Accepts intermediate patches (50+ MB) and full installs (1.5+ GB)
+function validatePWRFile(filePath, expectedSize = null) {
  try {
    if (!fs.existsSync(filePath)) {
      return false;
@@ -842,27 +931,20 @@ function validatePWRFile(filePath) {
    const stats = fs.statSync(filePath);
    const sizeInMB = stats.size / 1024 / 1024;

+    // PWR files should be at least 1 MB
    if (stats.size < 1024 * 1024) {
+      console.log(`[PWR Validation] File too small: ${sizeInMB.toFixed(2)} MB`);
      return false;
    }

-    // Check if file is under 1.5 GB (incomplete download)
-    if (sizeInMB < 1500) {
-      console.log(`[PWR Validation] File appears incomplete: ${sizeInMB.toFixed(2)} MB < 1.5 GB`);
+    // Validate against expected size if known (reject if < 99% of expected)
+    if (expectedSize && stats.size < expectedSize * 0.99) {
+      const expectedMB = expectedSize / 1024 / 1024;
+      console.log(`[PWR Validation] File truncated: ${sizeInMB.toFixed(2)} MB, expected ${expectedMB.toFixed(2)} MB`);
      return false;
    }

-    // Basic file header validation (PWR files should have specific headers)
-    const buffer = fs.readFileSync(filePath, { start: 0, end: 20 });
-    if (buffer.length < 10) {
-      return false;
-    }
-    
-    // Check for common PWR magic bytes or patterns
-    // This is a basic check - could be enhanced with actual PWR format specification
-    const header = buffer.toString('hex', 0, 10);
-    console.log(`[PWR Validation] File header: ${header}`);
-    
+    console.log(`[PWR Validation] File size: ${sizeInMB.toFixed(2)} MB - OK`);
    return true;
  } catch (error) {
    console.error(`[PWR Validation] Error:`, error.message);
--- a/backend/services/versionManager.js
+++ b/backend/services/versionManager.js
@@ -1,287 +1,500 @@
 const axios = require('axios');
 const crypto = require('crypto');
 const fs = require('fs');
+const path = require('path');
 const { getOS, getArch } = require('../utils/platformUtils');
-const { smartRequest } = require('../utils/proxyClient');

-const BASE_PATCH_URL = 'https://game-patches.hytale.com/patches';
-const MANIFEST_API = 'https://files.hytalef2p.com/api/patch_manifest';
-const NEW_API_URL = 'https://thecute.cloud/ShipOfYarn/api.php';
+// Patches base URL fetched dynamically via multi-source fallback chain
+const AUTH_DOMAIN = process.env.HYTALE_AUTH_DOMAIN || 'auth.sanasol.ws';
+const PATCHES_CONFIG_SOURCES = [
+  { type: 'http', url: `https://${AUTH_DOMAIN}/api/patches-config`, name: 'primary' },
+  { type: 'http', url: 'https://htdwnldsan.top/patches-config', name: 'backup-1' },
+  { type: 'http', url: 'https://dl1.htdwnldsan.top/patches-config', name: 'backup-2' },
+  { type: 'doh',  name: '_patches.htdwnldsan.top', name_label: 'dns-txt' },
+];
+const HARDCODED_FALLBACK = 'https://dl.vboro.de/patches';

-let apiCache = null;
-let apiCacheTime = 0;
-const API_CACHE_DURATION = 60000; // 1 minute
+// Alternative mirrors (non-Cloudflare) for regions where CF is blocked
+const NON_CF_MIRRORS = [
+  'https://dl1.htdwnldsan.top',
+  'https://htdwnldsan.top/patches',
+];

-async function fetchNewAPI() {
+// Fallback: latest known build number if manifest is unreachable
+const FALLBACK_LATEST_BUILD = 11;
+
+let patchesBaseUrl = null;
+let patchesConfigTime = 0;
+const PATCHES_CONFIG_CACHE_DURATION = 300000; // 5 minutes
+
+let manifestCache = null;
+let manifestCacheTime = 0;
+const MANIFEST_CACHE_DURATION = 60000; // 1 minute
+
+// Disk cache path for patches URL (survives restarts)
+function getDiskCachePath() {
+  const os = require('os');
+  const home = os.homedir();
+  let appDir;
+  if (process.platform === 'win32') {
+    appDir = path.join(home, 'AppData', 'Local', 'HytaleF2P');
+  } else if (process.platform === 'darwin') {
+    appDir = path.join(home, 'Library', 'Application Support', 'HytaleF2P');
+  } else {
+    appDir = path.join(home, '.hytalef2p');
+  }
+  return path.join(appDir, 'patches-url-cache.json');
+}
+
+function saveDiskCache(url) {
+  try {
+    const cachePath = getDiskCachePath();
+    const dir = path.dirname(cachePath);
+    if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
+    fs.writeFileSync(cachePath, JSON.stringify({ patches_url: url, ts: Date.now() }), 'utf8');
+  } catch (e) {
+    // Non-critical, ignore
+  }
+}
+
+function loadDiskCache() {
+  try {
+    const cachePath = getDiskCachePath();
+    if (fs.existsSync(cachePath)) {
+      const data = JSON.parse(fs.readFileSync(cachePath, 'utf8'));
+      if (data && data.patches_url) return data.patches_url;
+    }
+  } catch (e) {
+    // Non-critical, ignore
+  }
+  return null;
+}
+
+/**
+ * Fetch patches URL from a single HTTP config endpoint
+ */
+async function fetchFromHttp(url) {
+  const response = await axios.get(url, {
+    timeout: 8000,
+    headers: { 'User-Agent': 'Hytale-F2P-Launcher' }
+  });
+  if (response.data && response.data.patches_url) {
+    return response.data.patches_url.replace(/\/+$/, '');
+  }
+  throw new Error('Invalid response');
+}
+
+/**
+ * Fetch patches URL from DNS TXT record via DNS-over-HTTPS
+ */
+async function fetchFromDoh(recordName) {
+  const dohEndpoints = [
+    { url: 'https://dns.google/resolve', params: { name: recordName, type: 'TXT' } },
+    { url: 'https://cloudflare-dns.com/dns-query', params: { name: recordName, type: 'TXT' }, headers: { 'Accept': 'application/dns-json' } },
+  ];
+
+  for (const endpoint of dohEndpoints) {
+    try {
+      const response = await axios.get(endpoint.url, {
+        params: endpoint.params,
+        headers: { 'User-Agent': 'Hytale-F2P-Launcher', ...(endpoint.headers || {}) },
+        timeout: 5000
+      });
+      const answers = response.data && response.data.Answer;
+      if (answers && answers.length > 0) {
+        // TXT records are quoted, strip quotes
+        const txt = answers[0].data.replace(/^"|"$/g, '');
+        if (txt.startsWith('http')) return txt.replace(/\/+$/, '');
+      }
+    } catch (e) {
+      // Try next DoH endpoint
+    }
+  }
+  throw new Error('All DoH endpoints failed');
+}
+
+/**
+ * Fetch patches base URL with hardened multi-source fallback chain:
+ * 1. Memory cache (5 min)
+ * 2. HTTP: auth.sanasol.ws (primary)
+ * 3. HTTP: htdwnldsan.top (backup, different host/domain/registrar)
+ * 4. DNS TXT: _patches.htdwnldsan.top via DoH (different protocol layer)
+ * 5. Disk cache (survives restarts, never expires)
+ * 6. Hardcoded fallback URL (last resort)
+ */
+async function getPatchesBaseUrl() {
  const now = Date.now();

-  if (apiCache && (now - apiCacheTime) < API_CACHE_DURATION) {
-    console.log('[NewAPI] Using cached API data');
-    return apiCache;
+  // 1. Memory cache
+  if (patchesBaseUrl && (now - patchesConfigTime) < PATCHES_CONFIG_CACHE_DURATION) {
+    return patchesBaseUrl;
  }

+  // 2-4. Try all sources: HTTP endpoints first, then DoH
+  for (const source of PATCHES_CONFIG_SOURCES) {
    try {
-    console.log('[NewAPI] Fetching from:', NEW_API_URL);
-    const response = await axios.get(NEW_API_URL, {
-      timeout: 15000,
-      headers: {
-        'User-Agent': 'Hytale-F2P-Launcher'
+      let url;
+      if (source.type === 'http') {
+        console.log(`[Mirror] Trying ${source.name}: ${source.url}`);
+        url = await fetchFromHttp(source.url);
+      } else if (source.type === 'doh') {
+        console.log(`[Mirror] Trying ${source.name_label}: ${source.name}`);
+        url = await fetchFromDoh(source.name);
      }
-    });
-    
-    if (response.data && response.data.hytale) {
-      apiCache = response.data;
-      apiCacheTime = now;
-      console.log('[NewAPI] API data fetched and cached successfully');
-      return response.data;
-    } else {
-      throw new Error('Invalid API response structure');
-    }
-  } catch (error) {
-    console.error('[NewAPI] Error fetching API:', error.message);
-    if (apiCache) {
-      console.log('[NewAPI] Using expired cache due to error');
-      return apiCache;
-    }
-    throw error;
-  }
-}
-
-async function getLatestVersionFromNewAPI(branch = 'release') {
-  try {
-    const apiData = await fetchNewAPI();
-    const osName = getOS();
-    const arch = getArch();
-    
-    let osKey = osName;
-    if (osName === 'darwin') {
-      osKey = 'mac';
-    }
-    
-    const branchData = apiData.hytale[branch];
-    if (!branchData || !branchData[osKey]) {
-      throw new Error(`No data found for branch: ${branch}, OS: ${osKey}`);
-    }
-    
-    const osData = branchData[osKey];
-    
-    const versions = Object.keys(osData).filter(key => key.endsWith('.pwr'));
-    
-    if (versions.length === 0) {
-      throw new Error(`No .pwr files found for ${osKey}`);
-    }
-    
-    const versionNumbers = versions.map(v => {
-      const match = v.match(/v(\d+)/);
-      return match ? parseInt(match[1]) : 0;
-    });
-    
-    const latestVersionNumber = Math.max(...versionNumbers);
-    console.log(`[NewAPI] Latest version number: ${latestVersionNumber} for branch ${branch}`);
-    
-    return `v${latestVersionNumber}`;
-  } catch (error) {
-    console.error('[NewAPI] Error getting latest version:', error.message);
-    throw error;
-  }
-}
-
-async function getPWRUrlFromNewAPI(branch = 'release', version = 'v8') {
-  try {
-    const apiData = await fetchNewAPI();
-    const osName = getOS();
-    const arch = getArch();
-    
-    let osKey = osName;
-    if (osName === 'darwin') {
-      osKey = 'mac';
-    }
-    
-    let fileName;
-    if (osName === 'windows') {
-      fileName = `${version}-windows-amd64.pwr`;
-    } else if (osName === 'linux') {
-      fileName = `${version}-linux-amd64.pwr`;
-    } else if (osName === 'darwin') {
-      fileName = `${version}-darwin-arm64.pwr`;
-    }
-    
-    const branchData = apiData.hytale[branch];
-    if (!branchData || !branchData[osKey]) {
-      throw new Error(`No data found for branch: ${branch}, OS: ${osKey}`);
-    }
-    
-    const osData = branchData[osKey];
-    const url = osData[fileName];
-    
-    if (!url) {
-      throw new Error(`No URL found for ${fileName}`);
-    }
-    
-    console.log(`[NewAPI] URL for ${fileName}: ${url}`);
+      if (url) {
+        patchesBaseUrl = url;
+        patchesConfigTime = now;
+        saveDiskCache(url);
+        console.log(`[Mirror] Patches URL (via ${source.name || source.name_label}): ${url}`);
        return url;
-  } catch (error) {
-    console.error('[NewAPI] Error getting PWR URL:', error.message);
-    throw error;
      }
+    } catch (e) {
+      console.warn(`[Mirror] ${source.name || source.name_label} failed: ${e.message}`);
+    }
+  }
+
+  // 5. Stale memory cache (any age)
+  if (patchesBaseUrl) {
+    console.log('[Mirror] All sources failed, using stale memory cache:', patchesBaseUrl);
+    return patchesBaseUrl;
+  }
+
+  // 6. Disk cache (survives restarts)
+  const diskUrl = loadDiskCache();
+  if (diskUrl) {
+    patchesBaseUrl = diskUrl;
+    console.log('[Mirror] All sources failed, using disk cache:', diskUrl);
+    return diskUrl;
+  }
+
+  // 7. Hardcoded fallback
+  console.warn('[Mirror] All sources + caches exhausted, using hardcoded fallback:', HARDCODED_FALLBACK);
+  patchesBaseUrl = HARDCODED_FALLBACK;
+  return HARDCODED_FALLBACK;
+}
+
+/**
+ * Get all available mirror base URLs (primary + non-Cloudflare fallbacks)
+ * Used by download logic to retry on different mirrors when primary is blocked
+ */
+async function getAllMirrorUrls() {
+  const primary = await getPatchesBaseUrl();
+  // Deduplicate: don't include mirrors that match primary
+  const mirrors = NON_CF_MIRRORS.filter(m => m !== primary);
+  return [primary, ...mirrors];
+}
+
+/**
+ * Fetch the mirror manifest — tries primary URL first, then non-Cloudflare mirrors
+ */
+async function fetchMirrorManifest() {
+  const now = Date.now();
+
+  if (manifestCache && (now - manifestCacheTime) < MANIFEST_CACHE_DURATION) {
+    console.log('[Mirror] Using cached manifest');
+    return manifestCache;
+  }
+
+  const mirrors = await getAllMirrorUrls();
+
+  for (let i = 0; i < mirrors.length; i++) {
+    const baseUrl = mirrors[i];
+    const manifestUrl = `${baseUrl}/manifest.json`;
+    try {
+      console.log(`[Mirror] Fetching manifest from: ${manifestUrl}`);
+      const response = await axios.get(manifestUrl, {
+        timeout: 15000,
+        maxRedirects: 5,
+        headers: { 'User-Agent': 'Hytale-F2P-Launcher' }
+      });
+
+      if (response.data && response.data.files) {
+        manifestCache = response.data;
+        manifestCacheTime = now;
+        // If a non-primary mirror worked, switch to it for downloads too
+        if (i > 0) {
+          console.log(`[Mirror] Primary unreachable, switching to mirror: ${baseUrl}`);
+          patchesBaseUrl = baseUrl;
+          patchesConfigTime = now;
+          saveDiskCache(baseUrl);
+        }
+        console.log('[Mirror] Manifest fetched successfully');
+        return response.data;
+      }
+      throw new Error('Invalid manifest structure');
+    } catch (error) {
+      const isTimeout = error.code === 'ETIMEDOUT' || error.code === 'ECONNABORTED' || error.message.includes('timeout');
+      console.error(`[Mirror] Error fetching manifest from ${baseUrl}: ${error.message}${isTimeout ? ' (Cloudflare may be blocked)' : ''}`);
+      if (i < mirrors.length - 1) {
+        console.log(`[Mirror] Trying next mirror...`);
+      }
+    }
+  }
+
+  // All mirrors failed — use cached manifest if available
+  if (manifestCache) {
+    console.log('[Mirror] All mirrors failed, using expired cache');
+    return manifestCache;
+  }
+  throw new Error('All mirrors failed and no cached manifest available');
+}
+
+/**
+ * Parse manifest to get available patches for current platform
+ * Returns array of { from, to, key, size }
+ */
+function getPlatformPatches(manifest, branch = 'release') {
+  const os = getOS();
+  const arch = getArch();
+  const prefix = `${os}/${arch}/${branch}/`;
+  const patches = [];
+
+  for (const [key, info] of Object.entries(manifest.files)) {
+    if (key.startsWith(prefix) && key.endsWith('.pwr')) {
+      const filename = key.slice(prefix.length, -4); // e.g., "0_to_11"
+      const match = filename.match(/^(\d+)_to_(\d+)$/);
+      if (match) {
+        patches.push({
+          from: parseInt(match[1]),
+          to: parseInt(match[2]),
+          key,
+          size: info.size
+        });
+      }
+    }
+  }
+
+  return patches;
+}
+
+/**
+ * Find optimal patch path using BFS with download size minimization
+ * Returns array of { from, to, url, size, key } steps, or null if no path found
+ */
+async function findOptimalPatchPath(currentBuild, targetBuild, patches) {
+  if (currentBuild >= targetBuild) return [];
+
+  const baseUrl = await getPatchesBaseUrl();
+  const edges = {};
+  for (const patch of patches) {
+    if (!edges[patch.from]) edges[patch.from] = [];
+    edges[patch.from].push(patch);
+  }
+
+  const queue = [{ build: currentBuild, path: [], totalSize: 0 }];
+  let bestPath = null;
+  let bestSize = Infinity;
+
+  while (queue.length > 0) {
+    const { build, path, totalSize } = queue.shift();
+
+    if (build === targetBuild) {
+      if (totalSize < bestSize) {
+        bestPath = path;
+        bestSize = totalSize;
+      }
+      continue;
+    }
+
+    if (totalSize >= bestSize) continue;
+
+    const nextEdges = edges[build] || [];
+    for (const edge of nextEdges) {
+      if (edge.to <= build || edge.to > targetBuild) continue;
+      if (path.some(p => p.to === edge.to)) continue;
+
+      queue.push({
+        build: edge.to,
+        path: [...path, {
+          from: edge.from,
+          to: edge.to,
+          url: `${baseUrl}/${edge.key}`,
+          size: edge.size,
+          key: edge.key
+        }],
+        totalSize: totalSize + edge.size
+      });
+    }
+  }
+
+  return bestPath;
+}
+
+/**
+ * Get the optimal update plan from currentBuild to targetBuild
+ * Returns { steps: [{from, to, url, size}], totalSize, isFullInstall }
+ */
+async function getUpdatePlan(currentBuild, targetBuild, branch = 'release') {
+  const manifest = await fetchMirrorManifest();
+  const patches = getPlatformPatches(manifest, branch);
+
+  // Try optimal path
+  const steps = await findOptimalPatchPath(currentBuild, targetBuild, patches);
+
+  if (steps && steps.length > 0) {
+    const totalSize = steps.reduce((sum, s) => sum + s.size, 0);
+    console.log(`[Mirror] Update plan: ${steps.map(s => `${s.from}\u2192${s.to}`).join(' + ')} (${(totalSize / 1024 / 1024).toFixed(0)} MB)`);
+    return { steps, totalSize, isFullInstall: steps.length === 1 && steps[0].from === 0 };
+  }
+
+  // Fallback: full install 0 -> target
+  const fullPatch = patches.find(p => p.from === 0 && p.to === targetBuild);
+  if (fullPatch) {
+    const baseUrl = await getPatchesBaseUrl();
+    const step = {
+      from: 0,
+      to: targetBuild,
+      url: `${baseUrl}/${fullPatch.key}`,
+      size: fullPatch.size,
+      key: fullPatch.key
+    };
+    console.log(`[Mirror] Full install: 0\u2192${targetBuild} (${(fullPatch.size / 1024 / 1024).toFixed(0)} MB)`);
+    return { steps: [step], totalSize: fullPatch.size, isFullInstall: true };
+  }
+
+  throw new Error(`No patch path found from build ${currentBuild} to ${targetBuild} for ${getOS()}/${getArch()}`);
 }

 async function getLatestClientVersion(branch = 'release') {
  try {
-    console.log(`[NewAPI] Fetching latest client version from new API (branch: ${branch})...`);
+    console.log(`[Mirror] Fetching latest client version (branch: ${branch})...`);
+    const manifest = await fetchMirrorManifest();
+    const patches = getPlatformPatches(manifest, branch);

-    // Utiliser la nouvelle API
-    const latestVersion = await getLatestVersionFromNewAPI(branch);
-    console.log(`[NewAPI] Latest client version for ${branch}: ${latestVersion}`);
-    return latestVersion;
+    if (patches.length === 0) {
+      console.log(`[Mirror] No patches for branch '${branch}', using fallback`);
+      return `v${FALLBACK_LATEST_BUILD}`;
+    }

+    const latestBuild = Math.max(...patches.map(p => p.to));
+    console.log(`[Mirror] Latest client version: v${latestBuild}`);
+    return `v${latestBuild}`;
  } catch (error) {
-    console.error('[NewAPI] Error fetching client version from new API:', error.message);
-    console.log('[NewAPI] Falling back to old API...');
+    console.error('[Mirror] Error:', error.message);
+    return `v${FALLBACK_LATEST_BUILD}`;
+  }
+}
+
+/**
+ * Get PWR download URL for fresh install (0 -> target)
+ * Backward-compatible with old getPWRUrlFromNewAPI signature
+ * Checks mirror first, then constructs URL for the branch
+ */
+async function getPWRUrl(branch = 'release', version = 'v11') {
+  const targetBuild = extractVersionNumber(version);
+  const os = getOS();
+  const arch = getArch();

-    // Fallback vers l'ancienne API si la nouvelle échoue
  try {
-      const response = await smartRequest(`https://files.hytalef2p.com/api/version_client?branch=${branch}`, {
-        timeout: 40000,
-        headers: {
-          'User-Agent': 'Hytale-F2P-Launcher'
-        }
-      });
+    const manifest = await fetchMirrorManifest();
+    const patches = getPlatformPatches(manifest, branch);
+    const fullPatch = patches.find(p => p.from === 0 && p.to === targetBuild);

-      if (response.data && response.data.client_version) {
-        const version = response.data.client_version;
-        console.log(`Latest client version for ${branch} (old API): ${version}`);
-        return version;
+    if (fullPatch) {
+      const baseUrl = await getPatchesBaseUrl();
+      const url = `${baseUrl}/${fullPatch.key}`;
+      console.log(`[Mirror] PWR URL: ${url}`);
+      return url;
+    }
+
+    if (patches.length > 0) {
+      // Branch exists in mirror but no full patch for this target - construct URL
+      console.log(`[Mirror] No 0->${targetBuild} patch found, constructing URL`);
    } else {
-        console.log('Warning: Invalid API response, falling back to latest known version (v8)');
-        return 'v8';
-      }
-    } catch (fallbackError) {
-      console.error('Error fetching client version from old API:', fallbackError.message);
-      console.log('Warning: Both APIs unavailable, falling back to latest known version (v8)');
-      return 'v8';
-    }
+      console.log(`[Mirror] Branch '${branch}' not in mirror, constructing URL`);
    }
+  } catch (error) {
+    console.error('[Mirror] Error getting PWR URL:', error.message);
  }

-// Fonction utilitaire pour extraire le numéro de version
-// Supporte les formats: "7.pwr", "v8", "v8-windows-amd64.pwr", etc.
+  // Construct mirror URL (will work if patch was uploaded but manifest is stale)
+  const baseUrl = await getPatchesBaseUrl();
+  return `${baseUrl}/${os}/${arch}/${branch}/0_to_${targetBuild}.pwr`;
+}
+
+// Backward-compatible alias
+const getPWRUrlFromNewAPI = getPWRUrl;
+
+// Utility function to extract version number
+// Supports: "7.pwr", "v8", "v8-windows-amd64.pwr", "5_to_10", etc.
 function extractVersionNumber(version) {
  if (!version) return 0;

-  // Nouveau format: "v8" ou "v8-xxx.pwr"
+  // New format: "v8" or "v8-xxx.pwr"
  const vMatch = version.match(/v(\d+)/);
-  if (vMatch) {
-    return parseInt(vMatch[1]);
-  }
+  if (vMatch) return parseInt(vMatch[1]);

-  // Ancien format: "7.pwr"
+  // Old format: "7.pwr"
  const pwrMatch = version.match(/(\d+)\.pwr/);
-  if (pwrMatch) {
-    return parseInt(pwrMatch[1]);
-  }
+  if (pwrMatch) return parseInt(pwrMatch[1]);

-  // Fallback: essayer de parser directement
+  // Fallback
  const num = parseInt(version);
  return isNaN(num) ? 0 : num;
 }

-function buildArchiveUrl(buildNumber, branch = 'release') {
+async function buildArchiveUrl(buildNumber, branch = 'release') {
+  const baseUrl = await getPatchesBaseUrl();
  const os = getOS();
  const arch = getArch();
-  return `${BASE_PATCH_URL}/${os}/${arch}/${branch}/0/${buildNumber}.pwr`;
+  return `${baseUrl}/${os}/${arch}/${branch}/0_to_${buildNumber}.pwr`;
 }

 async function checkArchiveExists(buildNumber, branch = 'release') {
-  const url = buildArchiveUrl(buildNumber, branch);
+  const url = await buildArchiveUrl(buildNumber, branch);
  try {
    const response = await axios.head(url, { timeout: 10000 });
    return response.status === 200;
-  } catch (error) {
+  } catch {
    return false;
  }
 }

-async function discoverAvailableVersions(latestKnown, branch = 'release', maxProbe = 50) {
-  const available = [];
-  const latest = extractVersionNumber(latestKnown);
-  
-  for (let i = latest; i >= Math.max(1, latest - maxProbe); i--) {
-    const exists = await checkArchiveExists(i, branch);
-    if (exists) {
-      available.push(`${i}.pwr`);
-    }
-  }
-  
-  return available;
-}
-
-async function fetchPatchManifest(branch = 'release') {
+async function discoverAvailableVersions(latestKnown, branch = 'release') {
  try {
-    const os = getOS();
-    const arch = getArch();
-    const response = await smartRequest(`${MANIFEST_API}?branch=${branch}&os=${os}&arch=${arch}`, {
-      timeout: 10000
-    });
-    return response.data.patches || {};
-  } catch (error) {
-    console.error('Failed to fetch patch manifest:', error.message);
-    return {};
+    const manifest = await fetchMirrorManifest();
+    const patches = getPlatformPatches(manifest, branch);
+    const versions = [...new Set(patches.map(p => p.to))].sort((a, b) => b - a);
+    return versions.map(v => `${v}.pwr`);
+  } catch {
+    return [];
  }
 }

 async function extractVersionDetails(targetVersion, branch = 'release') {
  const buildNumber = extractVersionNumber(targetVersion);
-  const previousBuild = buildNumber - 1;
-  
-  const manifest = await fetchPatchManifest(branch);
-  const patchInfo = manifest[buildNumber];
+  const fullUrl = await buildArchiveUrl(buildNumber, branch);

  return {
    version: targetVersion,
-    buildNumber: buildNumber,
+    buildNumber,
    buildName: `HYTALE-Build-${buildNumber}`,
-    fullUrl: patchInfo?.original_url || buildArchiveUrl(buildNumber, branch),
-    differentialUrl: patchInfo?.patch_url || null,
-    checksum: patchInfo?.patch_hash || null,
-    sourceVersion: patchInfo?.from ? `${patchInfo.from}.pwr` : (previousBuild > 0 ? `${previousBuild}.pwr` : null),
-    isDifferential: !!patchInfo?.proper_patch,
-    releaseNotes: patchInfo?.patch_note || null
+    fullUrl,
+    differentialUrl: null,
+    checksum: null,
+    sourceVersion: null,
+    isDifferential: false,
+    releaseNotes: null
  };
 }

-function canUseDifferentialUpdate(currentVersion, targetDetails) {
-  if (!targetDetails) return false;
-  if (!targetDetails.differentialUrl) return false;
-  if (!targetDetails.isDifferential) return false;
-  
-  if (!currentVersion) return false;
-  
-  const currentBuild = extractVersionNumber(currentVersion);
-  const expectedSource = extractVersionNumber(targetDetails.sourceVersion);
-  
-  return currentBuild === expectedSource;
+function canUseDifferentialUpdate() {
+  // Differential updates are now handled via getUpdatePlan()
+  return false;
 }

 function needsIntermediatePatches(currentVersion, targetVersion) {
  if (!currentVersion) return [];
-  
  const current = extractVersionNumber(currentVersion);
  const target = extractVersionNumber(targetVersion);
-  
-  const intermediates = [];
-  for (let i = current + 1; i <= target; i++) {
-    intermediates.push(`${i}.pwr`);
-  }
-  
-  return intermediates;
+  if (current >= target) return [];
+  return [targetVersion];
 }

 async function computeFileChecksum(filePath) {
  return new Promise((resolve, reject) => {
    const hash = crypto.createHash('sha256');
    const stream = fs.createReadStream(filePath);
-    
    stream.on('data', data => hash.update(data));
    stream.on('end', () => resolve(hash.digest('hex')));
    stream.on('error', reject);
@@ -290,7 +503,6 @@ async function computeFileChecksum(filePath) {

 async function validateChecksum(filePath, expectedChecksum) {
  if (!expectedChecksum) return true;
-  
  const actualChecksum = await computeFileChecksum(filePath);
  return actualChecksum === expectedChecksum;
 }
@@ -299,7 +511,7 @@ function getInstalledClientVersion() {
  try {
    const { loadVersionClient } = require('../core/config');
    return loadVersionClient();
-  } catch (err) {
+  } catch {
    return null;
  }
 }
@@ -315,8 +527,13 @@ module.exports = {
  computeFileChecksum,
  validateChecksum,
  getInstalledClientVersion,
-  fetchNewAPI,
-  getLatestVersionFromNewAPI,
+  fetchMirrorManifest,
+  getPWRUrl,
  getPWRUrlFromNewAPI,
-  extractVersionNumber
+  getUpdatePlan,
+  extractVersionNumber,
+  getPlatformPatches,
+  findOptimalPatchPath,
+  getPatchesBaseUrl,
+  getAllMirrorUrls
 };
--- a/backend/utils/clientPatcher.js
+++ b/backend/utils/clientPatcher.js
@@ -9,7 +9,9 @@ const MAX_DOMAIN_LENGTH = 16;

 // DualAuth ByteBuddy Agent (runtime class transformation, no JAR modification)
 const DUALAUTH_AGENT_URL = 'https://github.com/sanasol/hytale-auth-server/releases/latest/download/dualauth-agent.jar';
+const DUALAUTH_AGENT_VERSION_API = 'https://api.github.com/repos/sanasol/hytale-auth-server/releases/latest';
 const DUALAUTH_AGENT_FILENAME = 'dualauth-agent.jar';
+const DUALAUTH_AGENT_VERSION_FILE = 'dualauth-agent.version';

 function getTargetDomain() {
  if (process.env.HYTALE_AUTH_DOMAIN) {
@@ -511,30 +513,70 @@ class ClientPatcher {
   */
  async ensureAgentAvailable(serverDir, progressCallback) {
    const agentPath = this.getAgentPath(serverDir);
+    const versionPath = path.join(serverDir, DUALAUTH_AGENT_VERSION_FILE);

    console.log('=== DualAuth Agent (ByteBuddy) ===');
    console.log(`Target: ${agentPath}`);

-    // Check if agent already exists and is valid
+    // Check local version and whether file exists
+    let localVersion = null;
+    let agentExists = false;
    if (fs.existsSync(agentPath)) {
      try {
        const stats = fs.statSync(agentPath);
        if (stats.size > 1024) {
-          console.log(`DualAuth Agent present (${(stats.size / 1024).toFixed(0)} KB)`);
-          if (progressCallback) progressCallback('DualAuth Agent ready', 100);
-          return { success: true, agentPath, alreadyExists: true };
+          agentExists = true;
+          if (fs.existsSync(versionPath)) {
+            localVersion = fs.readFileSync(versionPath, 'utf8').trim();
          }
-        // File exists but too small - corrupt, re-download
+        } else {
          console.log('Agent file appears corrupt, re-downloading...');
          fs.unlinkSync(agentPath);
+        }
      } catch (e) {
        console.warn('Could not check agent file:', e.message);
      }
    }

+    // Check for updates from GitHub
+    let remoteVersion = null;
+    let needsDownload = !agentExists;
+    if (agentExists) {
+      try {
+        if (progressCallback) progressCallback('Checking for agent updates...', 5);
+        const axios = require('axios');
+        const resp = await axios.get(DUALAUTH_AGENT_VERSION_API, {
+          timeout: 5000,
+          headers: { 'Accept': 'application/vnd.github.v3+json' }
+        });
+        remoteVersion = resp.data.tag_name; // e.g. "v1.1.10"
+        if (localVersion && localVersion === remoteVersion) {
+          console.log(`DualAuth Agent up to date (${localVersion})`);
+          if (progressCallback) progressCallback('DualAuth Agent ready', 100);
+          return { success: true, agentPath, alreadyExists: true, version: localVersion };
+        }
+        console.log(`Agent update available: ${localVersion || 'unknown'} → ${remoteVersion}`);
+        needsDownload = true;
+      } catch (e) {
+        // GitHub API failed - use existing agent if available
+        console.warn(`Could not check for updates: ${e.message}`);
+        if (agentExists) {
+          console.log(`Using existing agent (${localVersion || 'unknown version'})`);
+          if (progressCallback) progressCallback('DualAuth Agent ready', 100);
+          return { success: true, agentPath, alreadyExists: true, version: localVersion };
+        }
+      }
+    }
+
+    if (!needsDownload) {
+      if (progressCallback) progressCallback('DualAuth Agent ready', 100);
+      return { success: true, agentPath, alreadyExists: true, version: localVersion };
+    }
+
    // Download agent from GitHub releases
-    if (progressCallback) progressCallback('Downloading DualAuth Agent...', 20);
-    console.log(`Downloading from: ${DUALAUTH_AGENT_URL}`);
+    const action = agentExists ? 'Updating' : 'Downloading';
+    if (progressCallback) progressCallback(`${action} DualAuth Agent...`, 20);
+    console.log(`${action} from: ${DUALAUTH_AGENT_URL}`);

    try {
      // Ensure server directory exists
@@ -548,7 +590,7 @@ class ClientPatcher {
      const stream = await smartDownloadStream(DUALAUTH_AGENT_URL, (chunk, downloadedBytes, total) => {
        if (progressCallback && total) {
          const percent = 20 + Math.floor((downloadedBytes / total) * 70);
-          progressCallback(`Downloading agent... ${(downloadedBytes / 1024).toFixed(0)} KB`, percent);
+          progressCallback(`${action} agent... ${(downloadedBytes / 1024).toFixed(0)} KB`, percent);
        }
      });

@@ -575,9 +617,13 @@ class ClientPatcher {
      }
      fs.renameSync(tmpPath, agentPath);

-      console.log(`DualAuth Agent downloaded (${(stats.size / 1024).toFixed(0)} KB)`);
+      // Save version
+      const version = remoteVersion || 'unknown';
+      fs.writeFileSync(versionPath, version, 'utf8');
+
+      console.log(`DualAuth Agent ${agentExists ? 'updated' : 'downloaded'} (${(stats.size / 1024).toFixed(0)} KB, ${version})`);
      if (progressCallback) progressCallback('DualAuth Agent ready', 100);
-      return { success: true, agentPath };
+      return { success: true, agentPath, updated: agentExists, version };

    } catch (downloadError) {
      console.error(`Failed to download DualAuth Agent: ${downloadError.message}`);
@@ -586,6 +632,11 @@ class ClientPatcher {
      if (fs.existsSync(tmpPath)) {
        try { fs.unlinkSync(tmpPath); } catch (e) { /* ignore */ }
      }
+      // If we had an existing agent, still use it
+      if (agentExists) {
+        console.log('Using existing agent despite update failure');
+        return { success: true, agentPath, alreadyExists: true, version: localVersion };
+      }
      return { success: false, error: downloadError.message };
    }
  }
--- a/dev-app-update.yml
+++ b/dev-app-update.yml
@@ -1,3 +1,2 @@
-provider: github
-owner: amiayweb # Change to your own GitHub username
-repo: Hytale-F2P
+provider: generic
+url: https://git.sanhost.net/sanasol/hytale-f2p/releases/download/latest
--- a/main.js
+++ b/main.js
@@ -84,12 +84,12 @@ function setDiscordActivity() {
      largeImageText: 'Hytale F2P Launcher',
      buttons: [
        {
-          label: 'GitHub',
-          url: 'https://github.com/amiayweb/Hytale-F2P'
+          label: 'Download',
+          url: 'https://git.sanhost.net/sanasol/hytale-f2p/releases'
        },
        {
          label: 'Discord',
-          url: 'https://discord.gg/hf2pdc'
+          url: 'https://discord.gg/Fhbb9Yk5WW'
        }
      ]
    });
@@ -964,8 +964,8 @@ ipcMain.handle('open-external', async (event, url) => {

 ipcMain.handle('open-download-page', async () => {
  try {
-    // Open GitHub releases page for manual download
-    await shell.openExternal('https://github.com/amiayweb/Hytale-F2P/releases/latest');
+    // Open Forgejo releases page for manual download
+    await shell.openExternal('https://git.sanhost.net/sanasol/hytale-f2p/releases/latest');
    return { success: true };
  } catch (error) {
    console.error('Failed to open download page:', error);
--- a/package.json
+++ b/package.json
@@ -1,8 +1,8 @@
 {
  "name": "hytale-f2p-launcher",
-  "version": "2.2.2",
+  "version": "2.3.8",
  "description": "A modern, cross-platform launcher for Hytale with automatic updates and multi-client support",
-  "homepage": "https://github.com/amiayweb/Hytale-F2P",
+  "homepage": "https://git.sanhost.net/sanasol/hytale-f2p",
  "main": "main.js",
  "scripts": {
    "start": "electron .",
@@ -118,9 +118,8 @@
      "createStartMenuShortcut": true
    },
    "publish": {
-      "provider": "github",
-      "owner": "amiayweb",
-      "repo": "Hytale-F2P"
+      "provider": "generic",
+      "url": "https://git.sanhost.net/sanasol/hytale-f2p/releases/download/latest"
    }
  }
 }
--- a/test-uuid-persistence.js
+++ b/test-uuid-persistence.js
@@ -0,0 +1,523 @@
+#!/usr/bin/env node
+/**
+ * UUID Persistence Tests
+ *
+ * Simulates the exact conditions that caused character data loss:
+ * - Config file corruption during updates
+ * - File locks making config temporarily unreadable
+ * - Username re-entry after config wipe
+ *
+ * Run: node test-uuid-persistence.js
+ */
+
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+
+// Use a temp directory so we don't mess with real config
+const TEST_DIR = path.join(os.tmpdir(), 'hytale-uuid-test-' + Date.now());
+const CONFIG_FILE = path.join(TEST_DIR, 'config.json');
+const CONFIG_BACKUP = path.join(TEST_DIR, 'config.json.bak');
+const CONFIG_TEMP = path.join(TEST_DIR, 'config.json.tmp');
+const UUID_STORE_FILE = path.join(TEST_DIR, 'uuid-store.json');
+
+// Track test results
+let passed = 0;
+let failed = 0;
+const failures = [];
+
+function assert(condition, message) {
+  if (condition) {
+    passed++;
+    console.log(`  ✓ ${message}`);
+  } else {
+    failed++;
+    failures.push(message);
+    console.log(`  ✗ FAIL: ${message}`);
+  }
+}
+
+function assertEqual(actual, expected, message) {
+  if (actual === expected) {
+    passed++;
+    console.log(`  ✓ ${message}`);
+  } else {
+    failed++;
+    failures.push(`${message} (expected: ${expected}, got: ${actual})`);
+    console.log(`  ✗ FAIL: ${message} (expected: "${expected}", got: "${actual}")`);
+  }
+}
+
+function cleanup() {
+  try {
+    if (fs.existsSync(TEST_DIR)) {
+      fs.rmSync(TEST_DIR, { recursive: true });
+    }
+  } catch (e) {}
+}
+
+function setup() {
+  cleanup();
+  fs.mkdirSync(TEST_DIR, { recursive: true });
+}
+
+// ============================================================================
+// Inline the config functions so we can override paths
+// (We can't require config.js directly because it uses hardcoded getAppDir())
+// ============================================================================
+
+function validateConfig(config) {
+  if (!config || typeof config !== 'object') return false;
+  if (config.userUuids !== undefined && typeof config.userUuids !== 'object') return false;
+  if (config.username !== undefined && (typeof config.username !== 'string')) return false;
+  return true;
+}
+
+function loadConfig() {
+  try {
+    if (fs.existsSync(CONFIG_FILE)) {
+      const data = fs.readFileSync(CONFIG_FILE, 'utf8');
+      if (data.trim()) {
+        const config = JSON.parse(data);
+        if (validateConfig(config)) return config;
+        console.warn('[Config] Primary config invalid structure, trying backup...');
+      }
+    }
+  } catch (err) {
+    console.error('[Config] Failed to load primary config:', err.message);
+  }
+
+  try {
+    if (fs.existsSync(CONFIG_BACKUP)) {
+      const data = fs.readFileSync(CONFIG_BACKUP, 'utf8');
+      if (data.trim()) {
+        const config = JSON.parse(data);
+        if (validateConfig(config)) {
+          console.log('[Config] Recovered from backup successfully');
+          try { fs.writeFileSync(CONFIG_FILE, data, 'utf8'); } catch (e) {}
+          return config;
+        }
+      }
+    }
+  } catch (err) {}
+
+  return {};
+}
+
+function saveConfig(update) {
+  const maxRetries = 3;
+  for (let attempt = 1; attempt <= maxRetries; attempt++) {
+    try {
+      if (!fs.existsSync(TEST_DIR)) fs.mkdirSync(TEST_DIR, { recursive: true });
+
+      const currentConfig = loadConfig();
+
+      // SAFETY CHECK: refuse to save if file exists but loaded empty
+      if (Object.keys(currentConfig).length === 0 && fs.existsSync(CONFIG_FILE)) {
+        const fileSize = fs.statSync(CONFIG_FILE).size;
+        if (fileSize > 2) {
+          console.error(`[Config] REFUSING to save — loaded empty but file exists (${fileSize} bytes). Retrying...`);
+          const delay = attempt * 50; // shorter delay for tests
+          const start = Date.now();
+          while (Date.now() - start < delay) {}
+          continue;
+        }
+      }
+
+      const newConfig = { ...currentConfig, ...update };
+      const data = JSON.stringify(newConfig, null, 2);
+
+      fs.writeFileSync(CONFIG_TEMP, data, 'utf8');
+      const verification = JSON.parse(fs.readFileSync(CONFIG_TEMP, 'utf8'));
+      if (!validateConfig(verification)) throw new Error('Validation failed');
+
+      if (fs.existsSync(CONFIG_FILE)) {
+        try {
+          const currentData = fs.readFileSync(CONFIG_FILE, 'utf8');
+          if (currentData.trim()) fs.writeFileSync(CONFIG_BACKUP, currentData, 'utf8');
+        } catch (e) {}
+      }
+
+      fs.renameSync(CONFIG_TEMP, CONFIG_FILE);
+      return true;
+    } catch (err) {
+      try { if (fs.existsSync(CONFIG_TEMP)) fs.unlinkSync(CONFIG_TEMP); } catch (e) {}
+      if (attempt >= maxRetries) throw err;
+    }
+  }
+}
+
+function loadUuidStore() {
+  try {
+    if (fs.existsSync(UUID_STORE_FILE)) {
+      const data = fs.readFileSync(UUID_STORE_FILE, 'utf8');
+      if (data.trim()) return JSON.parse(data);
+    }
+  } catch (err) {}
+  return {};
+}
+
+function saveUuidStore(store) {
+  const tmpFile = UUID_STORE_FILE + '.tmp';
+  fs.writeFileSync(tmpFile, JSON.stringify(store, null, 2), 'utf8');
+  fs.renameSync(tmpFile, UUID_STORE_FILE);
+}
+
+function migrateUuidStoreIfNeeded() {
+  if (fs.existsSync(UUID_STORE_FILE)) return;
+  const config = loadConfig();
+  if (config.userUuids && Object.keys(config.userUuids).length > 0) {
+    console.log('[UUID Store] Migrating', Object.keys(config.userUuids).length, 'UUIDs');
+    saveUuidStore(config.userUuids);
+  }
+}
+
+function getUuidForUser(username) {
+  const { v4: uuidv4 } = require('uuid');
+  if (!username || !username.trim()) throw new Error('Username required');
+
+  const displayName = username.trim();
+  const normalizedLookup = displayName.toLowerCase();
+
+  migrateUuidStoreIfNeeded();
+
+  // 1. Check UUID store (source of truth)
+  const uuidStore = loadUuidStore();
+  const storeKey = Object.keys(uuidStore).find(k => k.toLowerCase() === normalizedLookup);
+  if (storeKey) {
+    const existingUuid = uuidStore[storeKey];
+    if (storeKey !== displayName) {
+      delete uuidStore[storeKey];
+      uuidStore[displayName] = existingUuid;
+      saveUuidStore(uuidStore);
+    }
+    // Sync to config (non-critical)
+    try {
+      const config = loadConfig();
+      const configUuids = config.userUuids || {};
+      const configKey = Object.keys(configUuids).find(k => k.toLowerCase() === normalizedLookup);
+      if (!configKey || configUuids[configKey] !== existingUuid) {
+        if (configKey) delete configUuids[configKey];
+        configUuids[displayName] = existingUuid;
+        saveConfig({ userUuids: configUuids });
+      }
+    } catch (e) {}
+    return existingUuid;
+  }
+
+  // 2. Fallback: check config.json
+  const config = loadConfig();
+  const userUuids = config.userUuids || {};
+  const configKey = Object.keys(userUuids).find(k => k.toLowerCase() === normalizedLookup);
+  if (configKey) {
+    const recoveredUuid = userUuids[configKey];
+    uuidStore[displayName] = recoveredUuid;
+    saveUuidStore(uuidStore);
+    return recoveredUuid;
+  }
+
+  // 3. New user — generate UUID
+  const newUuid = uuidv4();
+  uuidStore[displayName] = newUuid;
+  saveUuidStore(uuidStore);
+  userUuids[displayName] = newUuid;
+  saveConfig({ userUuids });
+  return newUuid;
+}
+
+// ============================================================================
+// OLD CODE (before fix) — for comparison testing
+// ============================================================================
+
+function getUuidForUser_OLD(username) {
+  const { v4: uuidv4 } = require('uuid');
+  if (!username || !username.trim()) throw new Error('Username required');
+  const displayName = username.trim();
+  const normalizedLookup = displayName.toLowerCase();
+
+  const config = loadConfig();
+  const userUuids = config.userUuids || {};
+  const existingKey = Object.keys(userUuids).find(k => k.toLowerCase() === normalizedLookup);
+
+  if (existingKey) {
+    return userUuids[existingKey];
+  }
+
+  // New user
+  const newUuid = uuidv4();
+  userUuids[displayName] = newUuid;
+  saveConfig({ userUuids });
+  return newUuid;
+}
+
+function saveConfig_OLD(update) {
+  // OLD saveConfig without safety check
+  if (!fs.existsSync(TEST_DIR)) fs.mkdirSync(TEST_DIR, { recursive: true });
+  const currentConfig = loadConfig();
+  // NO SAFETY CHECK — this is the bug
+  const newConfig = { ...currentConfig, ...update };
+  fs.writeFileSync(CONFIG_FILE, JSON.stringify(newConfig, null, 2), 'utf8');
+  return true;
+}
+
+// ============================================================================
+// TESTS
+// ============================================================================
+
+console.log('\n' + '='.repeat(70));
+console.log('UUID PERSISTENCE TESTS — Simulating update corruption scenarios');
+console.log('='.repeat(70));
+
+// --------------------------------------------------------------------------
+// TEST 1: Normal flow — UUID stays consistent
+// --------------------------------------------------------------------------
+console.log('\n--- Test 1: Normal flow — UUID stays consistent ---');
+setup();
+
+const uuid1 = getUuidForUser('SpecialK');
+const uuid2 = getUuidForUser('SpecialK');
+const uuid3 = getUuidForUser('specialk'); // case insensitive
+
+assertEqual(uuid1, uuid2, 'Same username returns same UUID');
+assertEqual(uuid1, uuid3, 'Case-insensitive lookup returns same UUID');
+assert(uuid1.match(/^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i), 'UUID is valid v4 format');
+
+// --------------------------------------------------------------------------
+// TEST 2: Simulate update corruption (THE BUG) — old code
+// --------------------------------------------------------------------------
+console.log('\n--- Test 2: OLD CODE — Config wipe during update loses UUID ---');
+setup();
+
+// Setup: player has UUID
+const oldConfig = { username: 'SpecialK', userUuids: { 'SpecialK': 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee' }, hasLaunchedBefore: true };
+fs.writeFileSync(CONFIG_FILE, JSON.stringify(oldConfig, null, 2), 'utf8');
+
+const uuidBefore = getUuidForUser_OLD('SpecialK');
+assertEqual(uuidBefore, 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee', 'UUID correct before corruption');
+
+// Simulate: config.json gets corrupted (loadConfig returns {} because file locked)
+// This simulates what happens when saveConfig reads an empty/locked file
+fs.writeFileSync(CONFIG_FILE, '', 'utf8'); // Simulate corruption: empty file
+
+// Old saveConfig behavior: reads empty, merges with update, saves
+// This wipes userUuids
+saveConfig_OLD({ hasLaunchedBefore: true });
+
+const configAfterCorruption = JSON.parse(fs.readFileSync(CONFIG_FILE, 'utf8'));
+assert(!configAfterCorruption.userUuids, 'OLD CODE: userUuids wiped after corruption');
+assert(!configAfterCorruption.username, 'OLD CODE: username wiped after corruption');
+
+// Player re-enters name, gets NEW UUID (character data lost!)
+const uuidAfterOld = getUuidForUser_OLD('SpecialK');
+assert(uuidAfterOld !== uuidBefore, 'OLD CODE: UUID changed after corruption (BUG!)');
+
+// --------------------------------------------------------------------------
+// TEST 3: NEW CODE — Config wipe during update, UUID survives via uuid-store
+// --------------------------------------------------------------------------
+console.log('\n--- Test 3: NEW CODE — Config wipe + UUID survives via uuid-store ---');
+setup();
+
+// Setup: player has UUID (stored in both config.json AND uuid-store.json)
+const initialConfig = { username: 'SpecialK', userUuids: { 'SpecialK': 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee' }, hasLaunchedBefore: true };
+fs.writeFileSync(CONFIG_FILE, JSON.stringify(initialConfig, null, 2), 'utf8');
+
+// First call migrates to uuid-store
+const uuidFirst = getUuidForUser('SpecialK');
+assertEqual(uuidFirst, 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee', 'UUID correct before corruption');
+assert(fs.existsSync(UUID_STORE_FILE), 'uuid-store.json created');
+
+// Simulate: config.json gets wiped (same as the update bug)
+fs.writeFileSync(CONFIG_FILE, '{}', 'utf8');
+
+// Verify config is empty
+const wipedConfig = loadConfig();
+assert(!wipedConfig.userUuids || Object.keys(wipedConfig.userUuids).length === 0, 'Config wiped — no userUuids');
+assert(!wipedConfig.username, 'Config wiped — no username');
+
+// Player re-enters same name → UUID recovered from uuid-store!
+const uuidAfterNew = getUuidForUser('SpecialK');
+assertEqual(uuidAfterNew, 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee', 'NEW CODE: UUID preserved after config wipe!');
+
+// --------------------------------------------------------------------------
+// TEST 4: saveConfig safety check — refuses to overwrite good data with empty
+// --------------------------------------------------------------------------
+console.log('\n--- Test 4: saveConfig safety check — blocks destructive writes ---');
+setup();
+
+// Setup: valid config file with data
+const goodConfig = { username: 'SpecialK', userUuids: { 'SpecialK': 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee' }, hasLaunchedBefore: true, installPath: 'C:\\Games\\Hytale' };
+fs.writeFileSync(CONFIG_FILE, JSON.stringify(goodConfig, null, 2), 'utf8');
+
+// Make the file temporarily unreadable by writing garbage (simulates file lock/corruption)
+const originalContent = fs.readFileSync(CONFIG_FILE, 'utf8');
+fs.writeFileSync(CONFIG_FILE, 'NOT VALID JSON!!!', 'utf8');
+
+// Try to save — should refuse because file exists but can't be parsed
+let saveThrew = false;
+try {
+  saveConfig({ someNewField: true });
+} catch (e) {
+  saveThrew = true;
+}
+
+// The file should still have the garbage (not overwritten with { someNewField: true })
+const afterContent = fs.readFileSync(CONFIG_FILE, 'utf8');
+
+// Restore original for backup recovery test
+fs.writeFileSync(CONFIG_FILE, JSON.stringify(goodConfig, null, 2), 'utf8');
+
+// Note: with invalid JSON, loadConfig returns {} and safety check triggers
+// The save may eventually succeed on retry if the file becomes readable
+// What matters is that it doesn't blindly overwrite
+assert(afterContent !== '{\n  "someNewField": true\n}', 'Safety check prevented blind overwrite of corrupted file');
+
+// --------------------------------------------------------------------------
+// TEST 5: Backup recovery — config.json corrupted, recovered from .bak
+// --------------------------------------------------------------------------
+console.log('\n--- Test 5: Backup recovery — auto-recover from .bak ---');
+setup();
+
+// Create config and backup
+const validConfig = { username: 'SpecialK', userUuids: { 'SpecialK': 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee' } };
+fs.writeFileSync(CONFIG_BACKUP, JSON.stringify(validConfig, null, 2), 'utf8');
+fs.writeFileSync(CONFIG_FILE, 'CORRUPTED', 'utf8');
+
+const recovered = loadConfig();
+assertEqual(recovered.username, 'SpecialK', 'Username recovered from backup');
+assert(recovered.userUuids && recovered.userUuids['SpecialK'] === 'aaaaaaaa-bbbb-4ccc-9ddd-eeeeeeeeeeee', 'UUID recovered from backup');
+
+// --------------------------------------------------------------------------
+// TEST 6: Full update simulation — the exact scenario from player report
+// --------------------------------------------------------------------------
+console.log('\n--- Test 6: Full update simulation (player report scenario) ---');
+setup();
+
+// Step 1: Player installs v2.3.4, sets username, plays game
+console.log('  Step 1: Player sets up profile...');
+saveConfig({ username: 'Special K', hasLaunchedBefore: true });
+const originalUuid = getUuidForUser('Special K');
+console.log(`  Original UUID: ${originalUuid}`);
+
+// Step 2: v2.3.5 auto-update — new app launches
+console.log('  Step 2: Simulating v2.3.5 update...');
+
+// Simulate the 3 saveConfig calls that happen during startup
+// But first, simulate config being temporarily locked (returns empty)
+const preUpdateContent = fs.readFileSync(CONFIG_FILE, 'utf8');
+fs.writeFileSync(CONFIG_FILE, '', 'utf8'); // Simulate: file empty during write (race condition)
+
+// These are the 3 calls from: profileManager.init, migrateUserDataToCentralized, handleFirstLaunchCheck
+// With our safety check, they should NOT wipe the data
+try { saveConfig({ hasLaunchedBefore: true }); } catch (e) { /* expected — safety check blocks it */ }
+
+// Simulate file becomes readable again (antivirus releases lock)
+fs.writeFileSync(CONFIG_FILE, preUpdateContent, 'utf8');
+
+// Step 3: Player re-enters username (because UI might show empty)
+console.log('  Step 3: Player re-enters username...');
+const postUpdateUuid = getUuidForUser('Special K');
+console.log(`  Post-update UUID: ${postUpdateUuid}`);
+
+assertEqual(postUpdateUuid, originalUuid, 'UUID survived the full update cycle!');
+
+// --------------------------------------------------------------------------
+// TEST 7: Multiple users — UUIDs stay independent
+// --------------------------------------------------------------------------
+console.log('\n--- Test 7: Multiple users — UUIDs stay independent ---');
+setup();
+
+const uuidAlice = getUuidForUser('Alice');
+const uuidBob = getUuidForUser('Bob');
+const uuidCharlie = getUuidForUser('Charlie');
+
+assert(uuidAlice !== uuidBob, 'Alice and Bob have different UUIDs');
+assert(uuidBob !== uuidCharlie, 'Bob and Charlie have different UUIDs');
+
+// Wipe config, all should survive
+fs.writeFileSync(CONFIG_FILE, '{}', 'utf8');
+
+assertEqual(getUuidForUser('Alice'), uuidAlice, 'Alice UUID survived config wipe');
+assertEqual(getUuidForUser('Bob'), uuidBob, 'Bob UUID survived config wipe');
+assertEqual(getUuidForUser('Charlie'), uuidCharlie, 'Charlie UUID survived config wipe');
+
+// --------------------------------------------------------------------------
+// TEST 8: UUID store deleted — recovery from config.json
+// --------------------------------------------------------------------------
+console.log('\n--- Test 8: UUID store deleted — recovery from config.json ---');
+setup();
+
+// Create UUID via normal flow (saves to both stores)
+const uuidOriginal = getUuidForUser('TestPlayer');
+
+// Delete uuid-store.json (simulates user manually deleting it or disk issue)
+fs.unlinkSync(UUID_STORE_FILE);
+assert(!fs.existsSync(UUID_STORE_FILE), 'uuid-store.json deleted');
+
+// UUID should be recovered from config.json
+const uuidRecovered = getUuidForUser('TestPlayer');
+assertEqual(uuidRecovered, uuidOriginal, 'UUID recovered from config.json after uuid-store deletion');
+assert(fs.existsSync(UUID_STORE_FILE), 'uuid-store.json recreated after recovery');
+
+// --------------------------------------------------------------------------
+// TEST 9: Both stores deleted — new UUID generated (fresh install)
+// --------------------------------------------------------------------------
+console.log('\n--- Test 9: Both stores deleted — new UUID (fresh install) ---');
+setup();
+
+const uuidFresh = getUuidForUser('NewPlayer');
+
+// Delete both
+fs.unlinkSync(UUID_STORE_FILE);
+fs.unlinkSync(CONFIG_FILE);
+
+const uuidAfterWipe = getUuidForUser('NewPlayer');
+assert(uuidAfterWipe !== uuidFresh, 'New UUID generated when both stores are gone (expected for true fresh install)');
+
+// --------------------------------------------------------------------------
+// TEST 10: Worst case — config.json wiped AND uuid-store.json exists
+// Simulates the EXACT player-reported scenario with new code
+// --------------------------------------------------------------------------
+console.log('\n--- Test 10: Exact player scenario with new code ---');
+setup();
+
+// Player has been playing for a while
+saveConfig({
+  username: 'Special K',
+  hasLaunchedBefore: true,
+  installPath: 'C:\\Games\\Hytale',
+  version_client: '2026.02.19-1a311a592',
+  version_branch: 'release',
+  userUuids: { 'Special K': '11111111-2222-4333-9444-555555555555' }
+});
+
+// First call creates uuid-store.json
+const originalUuid10 = getUuidForUser('Special K');
+assertEqual(originalUuid10, '11111111-2222-4333-9444-555555555555', 'Original UUID loaded');
+
+// BOOM: Update happens, config.json completely wiped
+fs.writeFileSync(CONFIG_FILE, '{}', 'utf8');
+
+// Username lost — player has to re-enter
+const loadedUsername = loadConfig().username;
+assert(!loadedUsername, 'Username is gone from config (simulating what player saw)');
+
+// Player types "Special K" again in settings
+saveConfig({ username: 'Special K' });
+
+// Player clicks Play — getUuidForUser called
+const recoveredUuid10 = getUuidForUser('Special K');
+assertEqual(recoveredUuid10, '11111111-2222-4333-9444-555555555555', 'UUID recovered — character data preserved!');
+
+// ============================================================================
+// RESULTS
+// ============================================================================
+console.log('\n' + '='.repeat(70));
+console.log(`RESULTS: ${passed} passed, ${failed} failed`);
+if (failed > 0) {
+  console.log('\nFailures:');
+  failures.forEach(f => console.log(`  ✗ ${f}`));
+}
+console.log('='.repeat(70));
+
+cleanup();
+process.exit(failed > 0 ? 1 : 0);