From f6a6f97e0b34149d4f442bcbb497aeb77285b6a7 Mon Sep 17 00:00:00 2001
From: lincube <lincube3@hotmail.com>
Date: Mon, 20 Apr 2026 07:48:53 +0800
Subject: [PATCH] chore: migrate release pipeline to signed filemap and wire
 rainyun s3

---
 .github/workflows/release.yml                 | 262 ++++++----
 .../pdc-incremental-migration/checklist.md    |  10 +
 .trae/specs/pdc-incremental-migration/spec.md |  30 ++
 .../specs/pdc-incremental-migration/tasks.md  |  12 +
 .../velopack-update-integration/checklist.md  |  10 +-
 .../specs/velopack-update-integration/spec.md |  25 +-
 .../velopack-update-integration/tasks.md      |  13 +-
 LanMountainDesktop.Launcher/AppJsonContext.cs |   3 -
 .../Models/ReleaseInfo.cs                     |   2 -
 .../Models/VelopackModels.cs                  |  23 -
 .../Services/Commands.cs                      |  20 -
 .../Services/UpdateCheckService.cs            |   6 +-
 .../Services/UpdateEngineService.cs           | 373 +-------------
 .../Models/AppSettingsSnapshot.cs             |   2 +-
 .../Services/PdcReleaseUpdateService.cs       | 464 ++++++++++++++++++
 .../Settings/SettingsDomainServices.cs        |  42 +-
 .../Services/UpdateSettingsValues.cs          |  21 +-
 .../Services/UpdateWorkflowService.cs         | 121 +++--
 .../ViewModels/SettingsViewModels.cs          |  25 +-
 phainon.yml                                   |  29 ++
 scripts/Generate-DeltaPackage.ps1             | 286 ++++++-----
 scripts/Sign-FileMap.ps1                      |  79 ++-
 22 files changed, 1078 insertions(+), 780 deletions(-)
 create mode 100644 .trae/specs/pdc-incremental-migration/checklist.md
 create mode 100644 .trae/specs/pdc-incremental-migration/spec.md
 create mode 100644 .trae/specs/pdc-incremental-migration/tasks.md
 delete mode 100644 LanMountainDesktop.Launcher/Models/VelopackModels.cs
 create mode 100644 LanMountainDesktop/Services/PdcReleaseUpdateService.cs
 create mode 100644 phainon.yml

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 6a205da..cb383ff 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -20,7 +20,6 @@ env:
   DOTNET_VERSION: '10.0.x'
   Solution_Name: LanMountainDesktop.slnx
   DOTNET_gcServer: 1
-  ENABLE_LEGACY_DELTA_FALLBACK: 'false'
 
 jobs:
   prepare:
@@ -318,56 +317,20 @@ jobs:
           Write-Host "Installer size: $([Math]::Round($installerFile.Length / 1MB, 2)) MB"
         shell: pwsh
 
-      - name: Install vpk
-        if: matrix.self_contained == true && matrix.arch == 'x64'
+      - name: Build Signed FileMap Update Package
+        if: matrix.self_contained == true
         run: |
           $ErrorActionPreference = "Stop"
-          dotnet tool uninstall --global vpk | Out-Null
-          if ($LASTEXITCODE -ne 0) {
-            Write-Host "vpk is not preinstalled, proceeding with fresh install."
-          }
-          dotnet tool install --global vpk --allow-roll-forward
-          "$env:USERPROFILE\\.dotnet\\tools" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
-          $env:PATH = "$env:USERPROFILE\\.dotnet\\tools;$env:PATH"
-          vpk -h
-        shell: pwsh
 
-      - name: Prepare Previous Velopack Full Package
-        if: matrix.self_contained == true && matrix.arch == 'x64'
-        run: |
-          $outputDir = "velopack-output"
-          New-Item -ItemType Directory -Path $outputDir -Force | Out-Null
-
-          try {
-            $headers = @{ "User-Agent" = "LanMountainDesktop-CI"; "Authorization" = "token ${{ secrets.GITHUB_TOKEN }}" }
-            $releases = Invoke-RestMethod -Uri "https://api.github.com/repos/${{ github.repository }}/releases?per_page=10" -Headers $headers
-            $previousRelease = $releases | Where-Object { -not $_.prerelease -and -not $_.draft } | Select-Object -First 1
-            if ($previousRelease) {
-              $previousFull = $previousRelease.assets |
-                Where-Object { $_.name -like "*-full.nupkg" } |
-                Select-Object -First 1
-              if ($previousFull) {
-                $dest = Join-Path $outputDir $previousFull.name
-                Invoke-WebRequest -Uri $previousFull.browser_download_url -OutFile $dest -Headers $headers
-                Write-Host "Downloaded previous package for Velopack delta generation."
-              } else {
-                Write-Host "No previous full package found. Velopack will generate full package only."
-              }
-            }
-          } catch {
-            Write-Host "Could not fetch previous release package: $_"
-          }
-        shell: pwsh
-
-      - name: Build Velopack Packages
-        if: matrix.self_contained == true && matrix.arch == 'x64'
-        run: |
           $version = "${{ needs.prepare.outputs.version }}"
           $arch = "${{ matrix.arch }}"
+          $platform = "windows-$arch"
           $publishDir = "publish/windows-$arch"
           $appDir = "app-$version"
           $currentAppPath = Join-Path $publishDir $appDir
-          $outputDir = "velopack-output"
+          $outputDir = Join-Path "delta-output" $platform
+          $generateScript = "scripts/Generate-DeltaPackage.ps1"
+          $signScript = "scripts/Sign-FileMap.ps1"
 
           if (-not (Test-Path $currentAppPath)) {
             Write-Error "Expected app directory not found: $currentAppPath"
@@ -375,54 +338,65 @@ jobs:
           }
 
           New-Item -ItemType Directory -Path $outputDir -Force | Out-Null
-          vpk pack `
-            --packId LanMountainDesktop `
-            --packVersion $version `
-            --packDir $currentAppPath `
-            --mainExe LanMountainDesktop.exe `
-            --outputDir $outputDir `
-            --channel win `
-            --noPortable `
-            --skipVeloAppCheck
-
-          if ($LASTEXITCODE -ne 0) {
-            Write-Error "Velopack packaging failed."
-            exit 1
-          }
-
-          Get-ChildItem -Path $outputDir -File | Select-Object Name,Length
-        shell: pwsh
-
-      - name: Legacy Delta Fallback (disabled by default)
-        if: matrix.self_contained == true && matrix.arch == 'x64' && env.ENABLE_LEGACY_DELTA_FALLBACK == 'true'
-        run: |
-          $version = "${{ needs.prepare.outputs.version }}"
-          $arch = "${{ matrix.arch }}"
-          $publishDir = "publish/windows-$arch"
-          $appDir = "app-$version"
-          $currentAppPath = Join-Path $publishDir $appDir
-          $outputDir = "delta-output"
-          $scriptPath = "scripts/Generate-DeltaPackage.ps1"
-
-          New-Item -ItemType Directory -Path $outputDir -Force | Out-Null
-          & $scriptPath `
+          & $generateScript `
             -PreviousVersion "0.0.0" `
             -CurrentVersion $version `
             -PreviousDir $currentAppPath `
             -CurrentDir $currentAppPath `
             -OutputDir $outputDir
+
+          $privateKeyPem = @'
+          ${{ secrets.PDC_SIGNING_KEY }}
+          '@.Trim()
+          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
+            $privateKeyPem = @'
+          ${{ secrets.UPDATE_PRIVATE_KEY_PEM }}
+          '@.Trim()
+          }
+          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
+            Write-Error "Missing required secret: PDC_SIGNING_KEY or UPDATE_PRIVATE_KEY_PEM"
+            exit 1
+          }
+
+          $privateKeyPem = $privateKeyPem -replace '\\n', "`n"
+          $tempDir = Join-Path $env:RUNNER_TEMP "update-signing"
+          New-Item -ItemType Directory -Path $tempDir -Force | Out-Null
+
+          $privateKeyPath = Join-Path $tempDir "private-key.pem"
+          $publicKeyPath = Join-Path $tempDir "public-key.pem"
+
+          Set-Content -Path $privateKeyPath -Value $privateKeyPem -NoNewline
+          $rsa = [System.Security.Cryptography.RSA]::Create()
+          $rsa.ImportFromPem($privateKeyPem)
+          $derivedPublicKey = $rsa.ExportRSAPublicKeyPem()
+          Set-Content -Path $publicKeyPath -Value $derivedPublicKey -NoNewline
+
+          $repoPublicKeyPath = "LanMountainDesktop.Launcher/Assets/public-key.pem"
+          $repoPublicKey = (Get-Content -Path $repoPublicKeyPath -Raw).Trim()
+          if ($repoPublicKey -ne $derivedPublicKey.Trim()) {
+            Write-Error "Configured signing private key does not match $repoPublicKeyPath. Keep keypair consistent before publishing."
+            exit 1
+          }
+
+          & $signScript `
+            -FilesJsonPath (Join-Path $outputDir "files.json") `
+            -PrivateKeyPath $privateKeyPath `
+            -OutputPath (Join-Path $outputDir "files.json.sig")
+
+          Copy-Item (Join-Path $outputDir "files.json") (Join-Path $outputDir "files-$platform.json") -Force
+          Copy-Item (Join-Path $outputDir "files.json.sig") (Join-Path $outputDir "files-$platform.json.sig") -Force
+          Copy-Item (Join-Path $outputDir "update.zip") (Join-Path $outputDir "update-$platform.zip") -Force
         shell: pwsh
 
-      - name: Upload Velopack Package
-        if: matrix.self_contained == true && matrix.arch == 'x64'
+      - name: Upload Signed FileMap Update Package
+        if: matrix.self_contained == true
         uses: actions/upload-artifact@v4
         with:
-          name: release-velopack-windows-x64
+          name: release-update-windows-${{ matrix.arch }}
           path: |
-            velopack-output/*.nupkg
-            velopack-output/releases.win.json
-            velopack-output/assets.win.json
-            velopack-output/RELEASES
+            delta-output/windows-${{ matrix.arch }}/files-windows-${{ matrix.arch }}.json
+            delta-output/windows-${{ matrix.arch }}/files-windows-${{ matrix.arch }}.json.sig
+            delta-output/windows-${{ matrix.arch }}/update-windows-${{ matrix.arch }}.zip
           if-no-files-found: error
           retention-days: 90
       - name: Upload Installer
@@ -630,6 +604,86 @@ jobs:
             exit 1
           fi
 
+      - name: Build Signed FileMap Update Package
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = "Stop"
+
+          $version = "${{ needs.prepare.outputs.version }}"
+          $platform = "linux-x64"
+          $publishDir = "publish/linux-x64"
+          $appDir = "app-$version"
+          $currentAppPath = Join-Path $publishDir $appDir
+          $outputDir = Join-Path "delta-output" $platform
+          $generateScript = "scripts/Generate-DeltaPackage.ps1"
+          $signScript = "scripts/Sign-FileMap.ps1"
+
+          if (-not (Test-Path $currentAppPath)) {
+            Write-Error "Expected app directory not found: $currentAppPath"
+            exit 1
+          }
+
+          New-Item -ItemType Directory -Path $outputDir -Force | Out-Null
+          & $generateScript `
+            -PreviousVersion "0.0.0" `
+            -CurrentVersion $version `
+            -PreviousDir $currentAppPath `
+            -CurrentDir $currentAppPath `
+            -OutputDir $outputDir
+
+          $privateKeyPem = @'
+          ${{ secrets.PDC_SIGNING_KEY }}
+          '@.Trim()
+          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
+            $privateKeyPem = @'
+          ${{ secrets.UPDATE_PRIVATE_KEY_PEM }}
+          '@.Trim()
+          }
+          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
+            Write-Error "Missing required secret: PDC_SIGNING_KEY or UPDATE_PRIVATE_KEY_PEM"
+            exit 1
+          }
+
+          $privateKeyPem = $privateKeyPem -replace '\\n', "`n"
+          $tempDir = Join-Path $env:RUNNER_TEMP "update-signing"
+          New-Item -ItemType Directory -Path $tempDir -Force | Out-Null
+
+          $privateKeyPath = Join-Path $tempDir "private-key.pem"
+          $publicKeyPath = Join-Path $tempDir "public-key.pem"
+
+          Set-Content -Path $privateKeyPath -Value $privateKeyPem -NoNewline
+          $rsa = [System.Security.Cryptography.RSA]::Create()
+          $rsa.ImportFromPem($privateKeyPem)
+          $derivedPublicKey = $rsa.ExportRSAPublicKeyPem()
+          Set-Content -Path $publicKeyPath -Value $derivedPublicKey -NoNewline
+
+          $repoPublicKeyPath = "LanMountainDesktop.Launcher/Assets/public-key.pem"
+          $repoPublicKey = (Get-Content -Path $repoPublicKeyPath -Raw).Trim()
+          if ($repoPublicKey -ne $derivedPublicKey.Trim()) {
+            Write-Error "Configured signing private key does not match $repoPublicKeyPath. Keep keypair consistent before publishing."
+            exit 1
+          }
+
+          & $signScript `
+            -FilesJsonPath (Join-Path $outputDir "files.json") `
+            -PrivateKeyPath $privateKeyPath `
+            -OutputPath (Join-Path $outputDir "files.json.sig")
+
+          Copy-Item (Join-Path $outputDir "files.json") (Join-Path $outputDir "files-$platform.json") -Force
+          Copy-Item (Join-Path $outputDir "files.json.sig") (Join-Path $outputDir "files-$platform.json.sig") -Force
+          Copy-Item (Join-Path $outputDir "update.zip") (Join-Path $outputDir "update-$platform.zip") -Force
+
+      - name: Upload Signed FileMap Update Package
+        uses: actions/upload-artifact@v4
+        with:
+          name: release-update-linux-x64
+          path: |
+            delta-output/linux-x64/files-linux-x64.json
+            delta-output/linux-x64/files-linux-x64.json.sig
+            delta-output/linux-x64/update-linux-x64.zip
+          if-no-files-found: error
+          retention-days: 90
+
       - name: Upload
         uses: actions/upload-artifact@v4
         with:
@@ -832,8 +886,8 @@ jobs:
           mkdir -p release-files
           # Copy installers and packages
           find artifacts -type f \( -name "*.exe" -o -name "*.deb" -o -name "*.dmg" \) -exec cp -v {} release-files/ \;
-          # Copy Velopack release feed and update packages
-          find artifacts -type f \( -name "releases.win.json" -o -name "assets.win.json" -o -name "RELEASES" -o -name "*.nupkg" \) -exec cp -v {} release-files/ \;
+          # Copy signed file-map incremental update assets
+          find artifacts -type f \( -name "files-*.json" -o -name "files-*.json.sig" -o -name "update-*.zip" \) -exec cp -v {} release-files/ \;
           echo ""
           echo "Files ready for release:"
           ls -lh release-files/ || echo "No files found in release-files"
@@ -846,6 +900,38 @@ jobs:
             exit 1
           fi
 
+      - name: Upload Incremental Assets to S3 (optional)
+        if: ${{ vars.S3_ENDPOINT != '' && vars.S3_BUCKET != '' && secrets.S3_ACCESS_KEY != '' && secrets.S3_SECRET_KEY != '' }}
+        env:
+          S3_ENDPOINT: ${{ vars.S3_ENDPOINT }}
+          S3_BUCKET: ${{ vars.S3_BUCKET }}
+          S3_REGION: ${{ vars.S3_REGION != '' && vars.S3_REGION || 'cn-nb1' }}
+          S3_ACCESS_KEY: ${{ secrets.S3_ACCESS_KEY }}
+          S3_SECRET_KEY: ${{ secrets.S3_SECRET_KEY }}
+          S3_OBJECT_PREFIX: lanmountain/distribution-v1
+        run: |
+          set -euo pipefail
+          python3 -m pip install --upgrade awscli
+
+          mkdir -p release-update-assets
+          find release-files -type f \( -name "files-*.json" -o -name "files-*.json.sig" -o -name "update-*.zip" \) -exec cp -v {} release-update-assets/ \;
+
+          asset_count=$(find release-update-assets -type f | wc -l)
+          if [ "$asset_count" -eq 0 ]; then
+            echo "Error: no incremental update assets found for S3 upload."
+            exit 1
+          fi
+
+          export AWS_ACCESS_KEY_ID="$S3_ACCESS_KEY"
+          export AWS_SECRET_ACCESS_KEY="$S3_SECRET_KEY"
+          export AWS_DEFAULT_REGION="$S3_REGION"
+
+          version_prefix="${S3_OBJECT_PREFIX}/${{ needs.prepare.outputs.version }}/"
+          latest_prefix="${S3_OBJECT_PREFIX}/latest/"
+
+          aws --endpoint-url "$S3_ENDPOINT" s3 sync release-update-assets "s3://${S3_BUCKET}/${version_prefix}" --only-show-errors
+          aws --endpoint-url "$S3_ENDPOINT" s3 sync release-update-assets "s3://${S3_BUCKET}/${latest_prefix}" --delete --only-show-errors
+
       - name: Create Release
         uses: ncipollo/release-action@v1
         with:
@@ -867,12 +953,12 @@ jobs:
 
             Installation: Double-click the .exe file and follow the wizard.
 
-            ### Incremental Update (Windows x64)
-            - **releases.win.json** - Velopack release feed consumed by the launcher update flow
-            - **LanMountainDesktop-<version>-full.nupkg** - full package
-            - **LanMountainDesktop-<version>-delta.nupkg** - delta package (when available)
+            ### Incremental Update Assets
+            - **files-windows-x64.json / files-windows-x64.json.sig / update-windows-x64.zip**
+            - **files-windows-x86.json / files-windows-x86.json.sig / update-windows-x86.zip**
+            - **files-linux-x64.json / files-linux-x64.json.sig / update-linux-x64.zip**
 
-            Existing users: The app will automatically detect and apply the incremental update on next launch.
+            Existing users: Launcher will detect platform-matching signed assets and apply update on next startup.
 
             ### Linux
             - **LanMountainDesktop-${{ needs.prepare.outputs.version }}-linux-x64.deb** - Debian package (x64)
diff --git a/.trae/specs/pdc-incremental-migration/checklist.md b/.trae/specs/pdc-incremental-migration/checklist.md
new file mode 100644
index 0000000..fabbce1
--- /dev/null
+++ b/.trae/specs/pdc-incremental-migration/checklist.md
@@ -0,0 +1,10 @@
+# Checklist
+
+- [x] `release.yml` produces signed FileMap incremental assets for Windows x64/x86 and Linux x64.
+- [x] `release.yml` no longer depends on `vpk`/VeloPack packaging.
+- [x] Launcher update engine applies only signed FileMap payload path.
+- [x] Host update workflow no longer expects `releases.win.json`/`*.nupkg`.
+- [x] Update source setting includes `pdc` and preserves GitHub fallback behavior.
+- [ ] CI run attached proving all release matrix jobs pass.
+- [ ] N-1 -> N incremental update verified on Windows x64/x86 and Linux x64.
+- [ ] Rollback verification report attached.
diff --git a/.trae/specs/pdc-incremental-migration/spec.md b/.trae/specs/pdc-incremental-migration/spec.md
new file mode 100644
index 0000000..ec308e8
--- /dev/null
+++ b/.trae/specs/pdc-incremental-migration/spec.md
@@ -0,0 +1,30 @@
+# PDC Incremental Update Migration
+
+## Goal
+
+Replace VeloPack-based incremental packaging with a unified signed FileMap pipeline and prepare for PDC/S3 distribution compatibility, while keeping Launcher installation, rollback, and update orchestration ownership unchanged.
+
+## Stage 1 (Completed in this round)
+
+- Release workflow outputs signed FileMap incremental assets as the primary path:
+  - `files-windows-x64.json` / `.sig` / `update-windows-x64.zip`
+  - `files-windows-x86.json` / `.sig` / `update-windows-x86.zip`
+  - `files-linux-x64.json` / `.sig` / `update-linux-x64.zip`
+- Launcher and host update runtime remove VeloPack branches and return to signed FileMap apply path.
+- Host update asset discovery supports platform-scoped names with fallback to legacy generic names.
+- Optional S3 sync publishes incremental assets in parallel with GitHub Release assets.
+
+## Stage 2 (In Progress)
+
+- Introduce PDC-compatible update source (`pdc`) with fallback to GitHub.
+- Add PDC metadata/latest/distribution API consumption abstraction.
+- Keep Launcher install/apply/rollback state machine unchanged.
+- Prepare `phainon.yml`-compatible release metadata for future PDCC integration.
+
+## Acceptance
+
+- `release.yml` no longer contains VeloPack packaging steps.
+- Windows x64/x86 and Linux x64 release jobs all upload signed FileMap incremental assets.
+- Host auto-update can detect and download platform-matching signed FileMap assets.
+- Launcher `update apply` succeeds with signed FileMap payload and rollback behavior remains unchanged.
+- Optional S3 upload step works when S3 secrets/vars are configured.
diff --git a/.trae/specs/pdc-incremental-migration/tasks.md b/.trae/specs/pdc-incremental-migration/tasks.md
new file mode 100644
index 0000000..aebd0db
--- /dev/null
+++ b/.trae/specs/pdc-incremental-migration/tasks.md
@@ -0,0 +1,12 @@
+# Tasks
+
+- [x] Remove VeloPack packaging from release workflow.
+- [x] Promote signed FileMap generation to release primary path.
+- [x] Output platform-scoped incremental assets for Windows x64/x86 and Linux x64.
+- [x] Remove launcher/runtime VeloPack branches.
+- [x] Update host asset discovery to platform-scoped signed FileMap naming.
+- [x] Add optional S3 sync for incremental assets.
+- [x] Extend update source values with `pdc`.
+- [x] Add PDC check fallback service skeleton in settings domain.
+- [ ] Add full PDC FileMap object-hash download/deploy path.
+- [ ] Add PDCC publish integration and `phainon.yml` CI publishing flow.
diff --git a/.trae/specs/velopack-update-integration/checklist.md b/.trae/specs/velopack-update-integration/checklist.md
index 04b7278..2641ed1 100644
--- a/.trae/specs/velopack-update-integration/checklist.md
+++ b/.trae/specs/velopack-update-integration/checklist.md
@@ -1,7 +1,5 @@
-# Checklist
+# Checklist (Deprecated)
 
-- [x] `releases.win.json` recognized by host update download flow.
-- [x] Launcher pending update check supports VeloPack payload.
-- [x] Launcher apply uses deployment markers (`.current/.partial/.destroy`) unchanged.
-- [x] Legacy script path retained as emergency fallback.
-- [ ] Staging verification report attached.
+- [x] Spec marked as deprecated.
+- [x] Active implementation ownership moved to `pdc-incremental-migration`.
+- [x] No release workflow dependency remains on VeloPack.
diff --git a/.trae/specs/velopack-update-integration/spec.md b/.trae/specs/velopack-update-integration/spec.md
index cb687c0..c080d00 100644
--- a/.trae/specs/velopack-update-integration/spec.md
+++ b/.trae/specs/velopack-update-integration/spec.md
@@ -1,16 +1,15 @@
-# VeloPack Update Integration
+# VeloPack Update Integration (Deprecated)
 
-## Goal
-Switch incremental package generation and release assets to VeloPack native outputs while keeping Launcher as the update installer and rollback authority.
+## Status
 
-## Requirements
-- CI/release pipeline produces `releases.win.json` and `*.nupkg` assets for Windows x64.
-- Launcher can detect pending VeloPack payload in `.launcher/update/incoming`.
-- Launcher applies update into new `app-*` deployment and preserves rollback snapshot behavior.
-- Existing launcher responsibilities (OOBE/startup/plugin upgrade) remain unchanged.
+This spec is deprecated and superseded by `.trae/specs/pdc-incremental-migration/`.
 
-## Acceptance
-- Build and quality workflows pass after migration changes.
-- Release workflow publishes VeloPack assets.
-- Launcher `update apply` succeeds with VeloPack full package payload.
-- Manual rollback still works after a VeloPack-based update.
+## Deprecation Reason
+
+- VeloPack native package generation introduced unstable release blocking (version format coupling and platform divergence).
+- The project has switched back to signed FileMap incremental assets as the primary update path.
+- Launcher remains the update installer/rollback authority; packaging and distribution are being migrated to PDC/S3-compatible flows.
+
+## Migration Note
+
+Use `.trae/specs/pdc-incremental-migration/spec.md` as the active authority for incremental update implementation and acceptance.
diff --git a/.trae/specs/velopack-update-integration/tasks.md b/.trae/specs/velopack-update-integration/tasks.md
index 2799d02..8ac2548 100644
--- a/.trae/specs/velopack-update-integration/tasks.md
+++ b/.trae/specs/velopack-update-integration/tasks.md
@@ -1,9 +1,6 @@
-# Tasks
+# Tasks (Deprecated)
 
-- [x] Fix Launcher `LoadingDetailsWindow.axaml` compile regression.
-- [x] Add VeloPack feed/package model support in Launcher update engine.
-- [x] Keep legacy delta flow behind disabled fallback switch.
-- [x] Migrate release workflow packaging assets to VeloPack outputs.
-- [x] Update host-side update workflow to download VeloPack payload files.
-- [ ] Run full release workflow dry-run on GitHub and validate artifacts.
-- [ ] Validate end-to-end update + rollback on a staging machine.
+- [x] Mark VeloPack integration spec as deprecated.
+- [x] Remove VeloPack runtime branches from launcher/host update path.
+- [x] Remove VeloPack release workflow packaging steps.
+- [ ] Keep archive for historical context only (no new implementation tasks here).
diff --git a/LanMountainDesktop.Launcher/AppJsonContext.cs b/LanMountainDesktop.Launcher/AppJsonContext.cs
index 210d0e0..7b02ce9 100644
--- a/LanMountainDesktop.Launcher/AppJsonContext.cs
+++ b/LanMountainDesktop.Launcher/AppJsonContext.cs
@@ -20,7 +20,4 @@ namespace LanMountainDesktop.Launcher;
 [JsonSerializable(typeof(GitHubRelease))]
 [JsonSerializable(typeof(GitHubAsset))]
 [JsonSerializable(typeof(List<GitHubRelease>))]
-[JsonSerializable(typeof(VelopackReleaseFeed))]
-[JsonSerializable(typeof(VelopackReleaseAsset))]
-[JsonSerializable(typeof(List<VelopackReleaseAsset>))]
 internal sealed partial class AppJsonContext : JsonSerializerContext;
diff --git a/LanMountainDesktop.Launcher/Models/ReleaseInfo.cs b/LanMountainDesktop.Launcher/Models/ReleaseInfo.cs
index 15fcb46..b74348a 100644
--- a/LanMountainDesktop.Launcher/Models/ReleaseInfo.cs
+++ b/LanMountainDesktop.Launcher/Models/ReleaseInfo.cs
@@ -11,8 +11,6 @@ public sealed class ReleaseInfo
     public required DateTime PublishedAt { get; init; }
     public required List<ReleaseAsset> Assets { get; init; }
     public string? Body { get; init; }
-    public string? VelopackFeedUrl { get; init; }
-    public string? VelopackLegacyReleasesUrl { get; init; }
 }
 
 /// <summary>
diff --git a/LanMountainDesktop.Launcher/Models/VelopackModels.cs b/LanMountainDesktop.Launcher/Models/VelopackModels.cs
deleted file mode 100644
index 7d568e1..0000000
--- a/LanMountainDesktop.Launcher/Models/VelopackModels.cs
+++ /dev/null
@@ -1,23 +0,0 @@
-namespace LanMountainDesktop.Launcher.Models;
-
-internal sealed class VelopackReleaseFeed
-{
-    public List<VelopackReleaseAsset> Assets { get; set; } = [];
-}
-
-internal sealed class VelopackReleaseAsset
-{
-    public string PackageId { get; set; } = string.Empty;
-
-    public string Version { get; set; } = string.Empty;
-
-    public string Type { get; set; } = string.Empty;
-
-    public string FileName { get; set; } = string.Empty;
-
-    public string? SHA1 { get; set; }
-
-    public string? SHA256 { get; set; }
-
-    public long Size { get; set; }
-}
diff --git a/LanMountainDesktop.Launcher/Services/Commands.cs b/LanMountainDesktop.Launcher/Services/Commands.cs
index 14289ff..1237b74 100644
--- a/LanMountainDesktop.Launcher/Services/Commands.cs
+++ b/LanMountainDesktop.Launcher/Services/Commands.cs
@@ -104,26 +104,6 @@ internal static class Commands
 
     private static async Task<LauncherResult> DownloadUpdatePayloadAsync(CommandContext context, UpdateEngineService updateEngine)
     {
-        var releasesUrl = context.GetOption("releases-url");
-        if (!string.IsNullOrWhiteSpace(releasesUrl))
-        {
-            var packageUrls = new List<string>();
-            var packageUrl = context.GetOption("package-url");
-            if (!string.IsNullOrWhiteSpace(packageUrl))
-            {
-                packageUrls.Add(packageUrl);
-            }
-
-            var packageUrlsCsv = context.GetOption("package-urls");
-            if (!string.IsNullOrWhiteSpace(packageUrlsCsv))
-            {
-                packageUrls.AddRange(packageUrlsCsv
-                    .Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries));
-            }
-
-            return await updateEngine.DownloadVelopackAsync(releasesUrl, packageUrls, CancellationToken.None).ConfigureAwait(false);
-        }
-
         return await updateEngine.DownloadAsync(
             context.GetOption("manifest-url") ?? throw new InvalidOperationException("Missing --manifest-url."),
             context.GetOption("signature-url") ?? throw new InvalidOperationException("Missing --signature-url."),
diff --git a/LanMountainDesktop.Launcher/Services/UpdateCheckService.cs b/LanMountainDesktop.Launcher/Services/UpdateCheckService.cs
index 9a17d4b..5f4e3dd 100644
--- a/LanMountainDesktop.Launcher/Services/UpdateCheckService.cs
+++ b/LanMountainDesktop.Launcher/Services/UpdateCheckService.cs
@@ -104,11 +104,7 @@ internal sealed class UpdateCheckService
                 Name = a.Name ?? "",
                 BrowserDownloadUrl = a.BrowserDownloadUrl ?? "",
                 Size = a.Size
-            }).ToList() ?? [],
-            VelopackFeedUrl = r.Assets?.FirstOrDefault(a =>
-                string.Equals(a.Name, "releases.win.json", StringComparison.OrdinalIgnoreCase))?.BrowserDownloadUrl,
-            VelopackLegacyReleasesUrl = r.Assets?.FirstOrDefault(a =>
-                string.Equals(a.Name, "RELEASES", StringComparison.OrdinalIgnoreCase))?.BrowserDownloadUrl
+            }).ToList() ?? []
         }).ToList() ?? [];
     }
 
diff --git a/LanMountainDesktop.Launcher/Services/UpdateEngineService.cs b/LanMountainDesktop.Launcher/Services/UpdateEngineService.cs
index 32d2aa8..a637a80 100644
--- a/LanMountainDesktop.Launcher/Services/UpdateEngineService.cs
+++ b/LanMountainDesktop.Launcher/Services/UpdateEngineService.cs
@@ -14,7 +14,6 @@ internal sealed class UpdateEngineService
     private const string SignedFileMapName = "files.json";
     private const string SignatureFileName = "files.json.sig";
     private const string ArchiveFileName = "update.zip";
-    private const string VelopackReleasesFileName = "releases.win.json";
     private const string PublicKeyFileName = "public-key.pem";
 
     private readonly DeploymentLocator _deploymentLocator;
@@ -34,16 +33,6 @@ internal sealed class UpdateEngineService
 
     public LauncherResult CheckPendingUpdate()
     {
-        var velopackFeedPath = Path.Combine(_incomingRoot, VelopackReleasesFileName);
-        if (File.Exists(velopackFeedPath))
-        {
-            var velopackResult = CheckVelopackPendingUpdate(velopackFeedPath);
-            if (velopackResult is not null)
-            {
-                return velopackResult;
-            }
-        }
-
         var fileMapPath = Path.Combine(_incomingRoot, SignedFileMapName);
         var archivePath = Path.Combine(_incomingRoot, ArchiveFileName);
         var signaturePath = Path.Combine(_incomingRoot, SignatureFileName);
@@ -82,47 +71,6 @@ internal sealed class UpdateEngineService
         };
     }
 
-    public async Task<LauncherResult> DownloadVelopackAsync(
-        string releasesJsonUrl,
-        IReadOnlyList<string> packageUrls,
-        CancellationToken cancellationToken)
-    {
-        if (string.IsNullOrWhiteSpace(releasesJsonUrl))
-        {
-            return Failed("update.download", "invalid_argument", "Missing releases feed url.");
-        }
-
-        Directory.CreateDirectory(_incomingRoot);
-
-        using var client = new HttpClient
-        {
-            Timeout = TimeSpan.FromMinutes(2)
-        };
-
-        var releasesPath = Path.Combine(_incomingRoot, VelopackReleasesFileName);
-        await DownloadToFileAsync(client, releasesJsonUrl, releasesPath, cancellationToken).ConfigureAwait(false);
-
-        foreach (var url in packageUrls.Where(u => !string.IsNullOrWhiteSpace(u)).Distinct(StringComparer.OrdinalIgnoreCase))
-        {
-            var fileName = Path.GetFileName(new Uri(url).AbsolutePath);
-            if (string.IsNullOrWhiteSpace(fileName))
-            {
-                continue;
-            }
-
-            var destination = Path.Combine(_incomingRoot, fileName);
-            await DownloadToFileAsync(client, url, destination, cancellationToken).ConfigureAwait(false);
-        }
-
-        return new LauncherResult
-        {
-            Success = true,
-            Stage = "update.download",
-            Code = "ok",
-            Message = "Velopack update payload downloaded."
-        };
-    }
-
     public async Task<LauncherResult> DownloadAsync(string manifestUrl, string signatureUrl, string archiveUrl, CancellationToken cancellationToken)
     {
         Directory.CreateDirectory(_incomingRoot);
@@ -167,12 +115,6 @@ internal sealed class UpdateEngineService
         Directory.CreateDirectory(_incomingRoot);
         Directory.CreateDirectory(_snapshotsRoot);
 
-        var velopackFeedPath = Path.Combine(_incomingRoot, VelopackReleasesFileName);
-        if (File.Exists(velopackFeedPath))
-        {
-            return await ApplyVelopackPendingUpdateAsync(velopackFeedPath).ConfigureAwait(false);
-        }
-
         var fileMapPath = Path.Combine(_incomingRoot, SignedFileMapName);
         var signaturePath = Path.Combine(_incomingRoot, SignatureFileName);
         var archivePath = Path.Combine(_incomingRoot, ArchiveFileName);
@@ -631,8 +573,7 @@ internal sealed class UpdateEngineService
                  {
                      Path.Combine(_incomingRoot, SignedFileMapName),
                      Path.Combine(_incomingRoot, SignatureFileName),
-                     Path.Combine(_incomingRoot, ArchiveFileName),
-                     Path.Combine(_incomingRoot, VelopackReleasesFileName)
+                     Path.Combine(_incomingRoot, ArchiveFileName)
                  })
         {
             try
@@ -646,17 +587,6 @@ internal sealed class UpdateEngineService
             {
             }
         }
-
-        try
-        {
-            foreach (var nupkgPath in Directory.EnumerateFiles(_incomingRoot, "*.nupkg", SearchOption.TopDirectoryOnly))
-            {
-                File.Delete(nupkgPath);
-            }
-        }
-        catch
-        {
-        }
     }
 
     private (bool Success, string Message) VerifySignature(string fileMapPath, string signaturePath)
@@ -724,307 +654,6 @@ internal sealed class UpdateEngineService
         return Convert.ToHexString(hash).ToLowerInvariant();
     }
 
-    private LauncherResult? CheckVelopackPendingUpdate(string feedPath)
-    {
-        try
-        {
-            var feed = JsonSerializer.Deserialize(File.ReadAllText(feedPath), AppJsonContext.Default.VelopackReleaseFeed);
-            if (feed?.Assets is null || feed.Assets.Count == 0)
-            {
-                return Failed("update.check", "invalid_manifest", "releases.win.json is invalid.");
-            }
-
-            var currentVersion = ParseVersionSafe(_deploymentLocator.GetCurrentVersion());
-            var latest = feed.Assets
-                .Where(a => string.Equals(a.Type, "Full", StringComparison.OrdinalIgnoreCase))
-                .Select(a => new { Asset = a, Version = ParseVersionSafe(a.Version) })
-                .Where(x => x.Version > currentVersion)
-                .OrderByDescending(x => x.Version)
-                .FirstOrDefault();
-
-            if (latest is null)
-            {
-                return new LauncherResult
-                {
-                    Success = true,
-                    Stage = "update.check",
-                    Code = "noop",
-                    Message = "No pending update for current version."
-                };
-            }
-
-            var packagePath = Path.Combine(_incomingRoot, latest.Asset.FileName);
-            if (!File.Exists(packagePath))
-            {
-                return Failed("update.check", "missing_payload", $"Missing Velopack package '{latest.Asset.FileName}'.");
-            }
-
-            return new LauncherResult
-            {
-                Success = true,
-                Stage = "update.check",
-                Code = "available",
-                Message = "Pending Velopack update is available.",
-                CurrentVersion = _deploymentLocator.GetCurrentVersion(),
-                TargetVersion = latest.Asset.Version
-            };
-        }
-        catch (Exception ex)
-        {
-            return Failed("update.check", "invalid_manifest", ex.Message);
-        }
-    }
-
-    private async Task<LauncherResult> ApplyVelopackPendingUpdateAsync(string feedPath)
-    {
-        VelopackReleaseFeed? feed;
-        try
-        {
-            var json = await File.ReadAllTextAsync(feedPath).ConfigureAwait(false);
-            feed = JsonSerializer.Deserialize(json, AppJsonContext.Default.VelopackReleaseFeed);
-        }
-        catch (Exception ex)
-        {
-            return Failed("update.apply", "invalid_manifest", $"Invalid releases feed: {ex.Message}");
-        }
-
-        if (feed?.Assets is null || feed.Assets.Count == 0)
-        {
-            return Failed("update.apply", "invalid_manifest", "releases.win.json has no assets.");
-        }
-
-        var currentDeployment = _deploymentLocator.FindCurrentDeploymentDirectory();
-        if (string.IsNullOrWhiteSpace(currentDeployment))
-        {
-            return Failed("update.apply", "no_current_deployment", "Current deployment not found.");
-        }
-
-        var currentVersionText = _deploymentLocator.GetCurrentVersion();
-        var currentVersion = ParseVersionSafe(currentVersionText);
-        var target = feed.Assets
-            .Where(a => string.Equals(a.Type, "Full", StringComparison.OrdinalIgnoreCase))
-            .Select(a => new { Asset = a, Version = ParseVersionSafe(a.Version) })
-            .Where(x => x.Version > currentVersion)
-            .OrderByDescending(x => x.Version)
-            .FirstOrDefault();
-
-        if (target is null)
-        {
-            return new LauncherResult
-            {
-                Success = true,
-                Stage = "update.apply",
-                Code = "noop",
-                Message = "No Velopack update payload found."
-            };
-        }
-
-        var packagePath = Path.Combine(_incomingRoot, target.Asset.FileName);
-        if (!File.Exists(packagePath))
-        {
-            return Failed("update.apply", "missing_payload", $"Missing Velopack package '{target.Asset.FileName}'.");
-        }
-
-        if (!VerifyVelopackPackageChecksum(packagePath, target.Asset))
-        {
-            return Failed("update.apply", "checksum_failed", "Velopack package checksum verification failed.");
-        }
-
-        var targetVersion = string.IsNullOrWhiteSpace(target.Asset.Version) ? currentVersionText : target.Asset.Version;
-        var targetDeployment = _deploymentLocator.BuildNextDeploymentDirectory(targetVersion);
-        var partialMarker = Path.Combine(targetDeployment, ".partial");
-        var snapshot = new SnapshotMetadata
-        {
-            SnapshotId = Guid.NewGuid().ToString("N"),
-            SourceVersion = currentVersionText,
-            TargetVersion = targetVersion,
-            CreatedAt = DateTimeOffset.UtcNow,
-            SourceDirectory = currentDeployment,
-            TargetDirectory = targetDeployment,
-            Status = "pending"
-        };
-        var snapshotPath = Path.Combine(_snapshotsRoot, $"{snapshot.SnapshotId}.json");
-        var extractRoot = Path.Combine(_incomingRoot, "extracted-velopack");
-
-        try
-        {
-            SaveSnapshot(snapshotPath, snapshot);
-
-            if (Directory.Exists(extractRoot))
-            {
-                Directory.Delete(extractRoot, true);
-            }
-
-            Directory.CreateDirectory(extractRoot);
-            ZipFile.ExtractToDirectory(packagePath, extractRoot, overwriteFiles: true);
-
-            var contentRoot = ResolveVelopackContentRoot(extractRoot);
-            if (contentRoot is null)
-            {
-                throw new InvalidOperationException("Unable to locate app payload in Velopack package.");
-            }
-
-            Directory.CreateDirectory(targetDeployment);
-            File.WriteAllText(partialMarker, string.Empty);
-            CopyDirectory(contentRoot, targetDeployment);
-
-            var hostExecutable = OperatingSystem.IsWindows() ? "LanMountainDesktop.exe" : "LanMountainDesktop";
-            if (!File.Exists(Path.Combine(targetDeployment, hostExecutable)))
-            {
-                throw new InvalidOperationException($"Host executable '{hostExecutable}' not found after applying Velopack package.");
-            }
-
-            ActivateDeployment(currentDeployment, targetDeployment);
-            snapshot.Status = "applied";
-            SaveSnapshot(snapshotPath, snapshot);
-            CleanupIncomingArtifacts();
-            CleanupDestroyedDeployments();
-
-            return new LauncherResult
-            {
-                Success = true,
-                Stage = "update.apply",
-                Code = "ok",
-                Message = $"Updated to {targetVersion}.",
-                CurrentVersion = currentVersionText,
-                TargetVersion = targetVersion
-            };
-        }
-        catch (Exception ex)
-        {
-            TryRollbackOnFailure(snapshot);
-            snapshot.Status = "rolled_back";
-            SaveSnapshot(snapshotPath, snapshot);
-            return new LauncherResult
-            {
-                Success = false,
-                Stage = "update.apply",
-                Code = "apply_failed",
-                Message = "Failed to apply update. Rolled back to previous version.",
-                ErrorMessage = ex.Message,
-                CurrentVersion = currentVersionText,
-                RolledBackTo = currentVersionText
-            };
-        }
-        finally
-        {
-            try
-            {
-                if (Directory.Exists(extractRoot))
-                {
-                    Directory.Delete(extractRoot, true);
-                }
-            }
-            catch
-            {
-            }
-        }
-    }
-
-    private static Version ParseVersionSafe(string? version)
-    {
-        if (string.IsNullOrWhiteSpace(version))
-        {
-            return new Version(0, 0, 0);
-        }
-
-        var normalized = version.Trim();
-        var separatorIndex = normalized.IndexOfAny(['-', '+', ' ']);
-        if (separatorIndex > 0)
-        {
-            normalized = normalized[..separatorIndex];
-        }
-
-        return Version.TryParse(normalized, out var parsed) ? parsed : new Version(0, 0, 0);
-    }
-
-    private static bool VerifyVelopackPackageChecksum(string packagePath, VelopackReleaseAsset asset)
-    {
-        try
-        {
-            if (!string.IsNullOrWhiteSpace(asset.SHA256))
-            {
-                var actualSha256 = ComputeSha256Hex(packagePath);
-                return string.Equals(actualSha256, asset.SHA256, StringComparison.OrdinalIgnoreCase);
-            }
-
-            if (!string.IsNullOrWhiteSpace(asset.SHA1))
-            {
-                using var stream = File.OpenRead(packagePath);
-                var sha1 = SHA1.HashData(stream);
-                var actualSha1 = Convert.ToHexString(sha1);
-                return string.Equals(actualSha1, asset.SHA1, StringComparison.OrdinalIgnoreCase);
-            }
-
-            return true;
-        }
-        catch
-        {
-            return false;
-        }
-    }
-
-    private static string? ResolveVelopackContentRoot(string extractRoot)
-    {
-        var hostExecutable = OperatingSystem.IsWindows() ? "LanMountainDesktop.exe" : "LanMountainDesktop";
-        var hostPath = Directory
-            .EnumerateFiles(extractRoot, hostExecutable, SearchOption.AllDirectories)
-            .FirstOrDefault();
-        if (!string.IsNullOrWhiteSpace(hostPath))
-        {
-            return Path.GetDirectoryName(hostPath);
-        }
-
-        // common nupkg layout fallback
-        var libRoot = Path.Combine(extractRoot, "lib");
-        if (Directory.Exists(libRoot))
-        {
-            var best = Directory.GetDirectories(libRoot, "*", SearchOption.TopDirectoryOnly)
-                .OrderByDescending(d => Directory.EnumerateFiles(d, "*", SearchOption.AllDirectories).Count())
-                .FirstOrDefault();
-            if (!string.IsNullOrWhiteSpace(best))
-            {
-                return best;
-            }
-        }
-
-        var candidate = Directory.GetDirectories(extractRoot, "*", SearchOption.TopDirectoryOnly)
-            .Where(d => !string.Equals(Path.GetFileName(d), "_rels", StringComparison.OrdinalIgnoreCase))
-            .Where(d => !string.Equals(Path.GetFileName(d), "package", StringComparison.OrdinalIgnoreCase))
-            .OrderByDescending(d => Directory.EnumerateFiles(d, "*", SearchOption.AllDirectories).Count())
-            .FirstOrDefault();
-
-        return candidate;
-    }
-
-    private static void CopyDirectory(string sourceDir, string targetDir)
-    {
-        foreach (var dirPath in Directory.EnumerateDirectories(sourceDir, "*", SearchOption.AllDirectories))
-        {
-            var relative = Path.GetRelativePath(sourceDir, dirPath);
-            Directory.CreateDirectory(Path.Combine(targetDir, relative));
-        }
-
-        foreach (var sourceFile in Directory.EnumerateFiles(sourceDir, "*", SearchOption.AllDirectories))
-        {
-            var relative = Path.GetRelativePath(sourceDir, sourceFile);
-            var destFile = Path.Combine(targetDir, relative);
-            var destDir = Path.GetDirectoryName(destFile);
-            if (!string.IsNullOrWhiteSpace(destDir))
-            {
-                Directory.CreateDirectory(destDir);
-            }
-            File.Copy(sourceFile, destFile, overwrite: true);
-        }
-    }
-
-    private static async Task DownloadToFileAsync(HttpClient client, string url, string destination, CancellationToken cancellationToken)
-    {
-        await using var stream = await client.GetStreamAsync(url, cancellationToken).ConfigureAwait(false);
-        await using var output = File.Create(destination);
-        await stream.CopyToAsync(output, cancellationToken).ConfigureAwait(false);
-    }
-
     private static void SaveSnapshot(string path, SnapshotMetadata snapshot)
     {
         File.WriteAllText(path, JsonSerializer.Serialize(snapshot, AppJsonContext.Default.SnapshotMetadata));
diff --git a/LanMountainDesktop/Models/AppSettingsSnapshot.cs b/LanMountainDesktop/Models/AppSettingsSnapshot.cs
index c487059..8902aab 100644
--- a/LanMountainDesktop/Models/AppSettingsSnapshot.cs
+++ b/LanMountainDesktop/Models/AppSettingsSnapshot.cs
@@ -85,7 +85,7 @@ public sealed class AppSettingsSnapshot
 
     public string UpdateMode { get; set; } = "download_then_confirm";
 
-    public string UpdateDownloadSource { get; set; } = "github";
+    public string UpdateDownloadSource { get; set; } = "pdc";
 
     public int UpdateDownloadThreads { get; set; } = 4;
 
diff --git a/LanMountainDesktop/Services/PdcReleaseUpdateService.cs b/LanMountainDesktop/Services/PdcReleaseUpdateService.cs
new file mode 100644
index 0000000..571053e
--- /dev/null
+++ b/LanMountainDesktop/Services/PdcReleaseUpdateService.cs
@@ -0,0 +1,464 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Net.Http;
+using System.Runtime.InteropServices;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace LanMountainDesktop.Services;
+
+/// <summary>
+/// Best-effort PDC client that maps PDC responses to the existing update result model.
+/// This keeps launcher update contracts stable while allowing a gradual migration.
+/// </summary>
+public sealed class PdcReleaseUpdateService : IDisposable
+{
+    private readonly HttpClient _httpClient;
+    private readonly bool _ownsHttpClient;
+
+    public PdcReleaseUpdateService(HttpClient? httpClient = null)
+    {
+        if (httpClient is null)
+        {
+            _httpClient = new HttpClient
+            {
+                Timeout = TimeSpan.FromSeconds(20)
+            };
+            _ownsHttpClient = true;
+        }
+        else
+        {
+            _httpClient = httpClient;
+            _ownsHttpClient = false;
+        }
+    }
+
+    public void Dispose()
+    {
+        if (_ownsHttpClient)
+        {
+            _httpClient.Dispose();
+        }
+    }
+
+    public Task<UpdateCheckResult> CheckForUpdatesAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        CancellationToken cancellationToken = default)
+    {
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: false, cancellationToken);
+    }
+
+    public Task<UpdateCheckResult> ForceCheckForUpdatesAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        CancellationToken cancellationToken = default)
+    {
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: true, cancellationToken);
+    }
+
+    private async Task<UpdateCheckResult> CheckForUpdatesCoreAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        bool isForce,
+        CancellationToken cancellationToken)
+    {
+        var normalizedCurrentVersion = NormalizeVersion(currentVersion);
+        var normalizedCurrentVersionText = FormatVersionText(normalizedCurrentVersion);
+        var endpoint = ResolveEndpoint();
+
+        if (string.IsNullOrWhiteSpace(endpoint))
+        {
+            return new UpdateCheckResult(
+                Success: false,
+                IsUpdateAvailable: false,
+                CurrentVersionText: normalizedCurrentVersionText,
+                LatestVersionText: "-",
+                Release: null,
+                PreferredAsset: null,
+                ErrorMessage: "PDC endpoint is not configured.",
+                ForceMode: isForce);
+        }
+
+        try
+        {
+            var metadataUrl = BuildUri(endpoint, "api/v1/public/distributions/metadata");
+            var metadata = await GetContentNodeAsync(metadataUrl, cancellationToken).ConfigureAwait(false);
+
+            var channelId = ResolveChannelId(metadata, includePrerelease);
+            if (string.IsNullOrWhiteSpace(channelId))
+            {
+                channelId = includePrerelease ? "preview" : "stable";
+            }
+
+            var latestUrl = BuildUri(
+                endpoint,
+                $"api/v1/public/distributions/latest/{Uri.EscapeDataString(channelId)}?appVersion={Uri.EscapeDataString(normalizedCurrentVersionText)}");
+            var latestNode = await GetContentNodeAsync(latestUrl, cancellationToken).ConfigureAwait(false);
+
+            var latestVersionText = ReadString(latestNode, "version") ?? "-";
+            if (!TryParseVersion(latestVersionText, out var latestVersion) || latestVersion is null)
+            {
+                return new UpdateCheckResult(
+                    Success: false,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: "PDC latest distribution version is invalid.",
+                    ForceMode: isForce);
+            }
+
+            var distributionId = ReadString(latestNode, "distributionId");
+            if (string.IsNullOrWhiteSpace(distributionId))
+            {
+                return new UpdateCheckResult(
+                    Success: false,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: "PDC latest distribution id is missing.",
+                    ForceMode: isForce);
+            }
+
+            var hasUpdate = latestVersion > normalizedCurrentVersion;
+            if (!isForce && !hasUpdate)
+            {
+                return new UpdateCheckResult(
+                    Success: true,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: null,
+                    ForceMode: false);
+            }
+
+            var subChannel = ResolveSubChannel();
+            var distributionUrl = BuildUri(
+                endpoint,
+                $"api/v1/public/distributions/{Uri.EscapeDataString(distributionId)}/{Uri.EscapeDataString(subChannel)}");
+            var distributionNode = await GetContentNodeAsync(distributionUrl, cancellationToken).ConfigureAwait(false);
+
+            var assets = ResolveAssets(distributionNode);
+            if (assets.Count == 0)
+            {
+                return new UpdateCheckResult(
+                    Success: false,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: "PDC distribution response does not expose downloadable update assets.",
+                    ForceMode: isForce);
+            }
+
+            var release = new GitHubReleaseInfo(
+                TagName: $"v{latestVersionText}",
+                Name: $"PDC Distribution {latestVersionText}",
+                IsPrerelease: includePrerelease,
+                IsDraft: false,
+                PublishedAt: DateTimeOffset.UtcNow,
+                Assets: assets);
+
+            return new UpdateCheckResult(
+                Success: true,
+                IsUpdateAvailable: true,
+                CurrentVersionText: normalizedCurrentVersionText,
+                LatestVersionText: latestVersionText,
+                Release: release,
+                PreferredAsset: null,
+                ErrorMessage: null,
+                ForceMode: isForce);
+        }
+        catch (OperationCanceledException)
+        {
+            throw;
+        }
+        catch (Exception ex)
+        {
+            return new UpdateCheckResult(
+                Success: false,
+                IsUpdateAvailable: false,
+                CurrentVersionText: normalizedCurrentVersionText,
+                LatestVersionText: "-",
+                Release: null,
+                PreferredAsset: null,
+                ErrorMessage: $"PDC request failed: {ex.Message}",
+                ForceMode: isForce);
+        }
+    }
+
+    private async Task<JsonElement> GetContentNodeAsync(string url, CancellationToken cancellationToken)
+    {
+        using var request = new HttpRequestMessage(HttpMethod.Get, url);
+        var token = ResolveToken();
+        if (!string.IsNullOrWhiteSpace(token))
+        {
+            request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
+        }
+
+        using var response = await _httpClient.SendAsync(request, cancellationToken).ConfigureAwait(false);
+        var body = await response.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+        if (!response.IsSuccessStatusCode)
+        {
+            throw new InvalidOperationException($"HTTP {(int)response.StatusCode}: {Truncate(body, 180)}");
+        }
+
+        using var document = JsonDocument.Parse(body);
+        var root = document.RootElement;
+        if (root.ValueKind == JsonValueKind.Object &&
+            root.TryGetProperty("content", out var content))
+        {
+            return content.Clone();
+        }
+
+        return root.Clone();
+    }
+
+    private static IReadOnlyList<GitHubReleaseAsset> ResolveAssets(JsonElement distributionNode)
+    {
+        var assets = new List<GitHubReleaseAsset>();
+        if (distributionNode.ValueKind != JsonValueKind.Object)
+        {
+            return assets;
+        }
+
+        if (distributionNode.TryGetProperty("assets", out var assetsNode) &&
+            assetsNode.ValueKind == JsonValueKind.Array)
+        {
+            foreach (var assetNode in assetsNode.EnumerateArray())
+            {
+                if (assetNode.ValueKind != JsonValueKind.Object)
+                {
+                    continue;
+                }
+
+                var name = ReadString(assetNode, "name");
+                var url = ReadString(assetNode, "url") ??
+                          ReadString(assetNode, "downloadUrl") ??
+                          ReadString(assetNode, "browserDownloadUrl");
+                if (string.IsNullOrWhiteSpace(name) || string.IsNullOrWhiteSpace(url))
+                {
+                    continue;
+                }
+
+                var size = ReadInt64(assetNode, "size") ?? 0L;
+                var sha256 = ReadString(assetNode, "sha256");
+                assets.Add(new GitHubReleaseAsset(name, url, size, sha256));
+            }
+        }
+
+        if (assets.Count > 0)
+        {
+            return assets;
+        }
+
+        // Field-level fallback for service-side URL projection.
+        var manifestUrl = ReadString(distributionNode, "manifestUrl")
+                          ?? ReadString(distributionNode, "fileMapUrl");
+        var signatureUrl = ReadString(distributionNode, "signatureUrl")
+                           ?? ReadString(distributionNode, "fileMapSignatureUrl");
+        var archiveUrl = ReadString(distributionNode, "archiveUrl")
+                         ?? ReadString(distributionNode, "updateArchiveUrl")
+                         ?? ReadString(distributionNode, "payloadUrl");
+
+        if (!string.IsNullOrWhiteSpace(manifestUrl))
+        {
+            assets.Add(new GitHubReleaseAsset("files.json", manifestUrl, 0, null));
+        }
+
+        if (!string.IsNullOrWhiteSpace(signatureUrl))
+        {
+            assets.Add(new GitHubReleaseAsset("files.json.sig", signatureUrl, 0, null));
+        }
+
+        if (!string.IsNullOrWhiteSpace(archiveUrl))
+        {
+            assets.Add(new GitHubReleaseAsset("update.zip", archiveUrl, 0, null));
+        }
+
+        return assets;
+    }
+
+    private static string ResolveChannelId(JsonElement metadataNode, bool includePrerelease)
+    {
+        if (metadataNode.ValueKind != JsonValueKind.Object ||
+            !metadataNode.TryGetProperty("channels", out var channelsNode))
+        {
+            return includePrerelease ? "preview" : "stable";
+        }
+
+        var defaultChannelId = ReadString(metadataNode, "defaultChannelId") ?? string.Empty;
+        if (channelsNode.ValueKind != JsonValueKind.Object)
+        {
+            return defaultChannelId;
+        }
+
+        string? matchedPreview = null;
+        string? matchedStable = null;
+
+        foreach (var channel in channelsNode.EnumerateObject())
+        {
+            var name = ReadString(channel.Value, "name") ?? channel.Name;
+            if (string.IsNullOrWhiteSpace(matchedPreview) &&
+                (name.Contains("preview", StringComparison.OrdinalIgnoreCase) ||
+                 name.Contains("beta", StringComparison.OrdinalIgnoreCase) ||
+                 name.Contains("dev", StringComparison.OrdinalIgnoreCase)))
+            {
+                matchedPreview = channel.Name;
+            }
+
+            if (string.IsNullOrWhiteSpace(matchedStable) &&
+                (name.Contains("stable", StringComparison.OrdinalIgnoreCase) ||
+                 name.Contains("release", StringComparison.OrdinalIgnoreCase)))
+            {
+                matchedStable = channel.Name;
+            }
+        }
+
+        if (includePrerelease)
+        {
+            return matchedPreview ?? defaultChannelId ?? "preview";
+        }
+
+        return matchedStable ?? defaultChannelId ?? "stable";
+    }
+
+    private static string ResolveSubChannel()
+    {
+        var configured = Environment.GetEnvironmentVariable("LANMOUNTAIN_PDC_SUBCHANNEL")
+                         ?? Environment.GetEnvironmentVariable("PDC_SUBCHANNEL");
+        if (!string.IsNullOrWhiteSpace(configured))
+        {
+            return configured.Trim();
+        }
+
+        var os = OperatingSystem.IsWindows()
+            ? "windows"
+            : OperatingSystem.IsLinux()
+                ? "linux"
+                : OperatingSystem.IsMacOS()
+                    ? "macos"
+                    : "unknown";
+
+        var arch = RuntimeInformation.OSArchitecture switch
+        {
+            Architecture.X86 => "x86",
+            Architecture.Arm => "arm",
+            Architecture.Arm64 => "arm64",
+            _ => "x64"
+        };
+
+        return $"{os}_{arch}_release_folderClassic";
+    }
+
+    private static string? ResolveEndpoint()
+    {
+        var endpoint = Environment.GetEnvironmentVariable("LANMOUNTAIN_PDC_ENDPOINT")
+                      ?? Environment.GetEnvironmentVariable("PDC_ENDPOINT");
+        return string.IsNullOrWhiteSpace(endpoint) ? null : endpoint.Trim().TrimEnd('/');
+    }
+
+    private static string? ResolveToken()
+    {
+        var token = Environment.GetEnvironmentVariable("LANMOUNTAIN_PDC_TOKEN")
+                    ?? Environment.GetEnvironmentVariable("PDC_TOKEN");
+        return string.IsNullOrWhiteSpace(token) ? null : token.Trim();
+    }
+
+    private static string BuildUri(string endpoint, string relativePath)
+    {
+        return $"{endpoint.TrimEnd('/')}/{relativePath.TrimStart('/')}";
+    }
+
+    private static string? ReadString(JsonElement node, string propertyName)
+    {
+        if (node.ValueKind != JsonValueKind.Object || !node.TryGetProperty(propertyName, out var value))
+        {
+            return null;
+        }
+
+        return value.ValueKind == JsonValueKind.String
+            ? value.GetString()
+            : value.ToString();
+    }
+
+    private static long? ReadInt64(JsonElement node, string propertyName)
+    {
+        if (node.ValueKind != JsonValueKind.Object || !node.TryGetProperty(propertyName, out var value))
+        {
+            return null;
+        }
+
+        if (value.TryGetInt64(out var number))
+        {
+            return number;
+        }
+
+        var text = value.ToString();
+        return long.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var parsed)
+            ? parsed
+            : null;
+    }
+
+    private static bool TryParseVersion(string? value, out Version? version)
+    {
+        version = null;
+        if (string.IsNullOrWhiteSpace(value))
+        {
+            return false;
+        }
+
+        var normalized = value.Trim().TrimStart('v', 'V');
+        var separatorIndex = normalized.IndexOfAny(['-', '+', ' ']);
+        if (separatorIndex > 0)
+        {
+            normalized = normalized[..separatorIndex];
+        }
+
+        if (!Version.TryParse(normalized, out var parsed))
+        {
+            return false;
+        }
+
+        version = NormalizeVersion(parsed);
+        return true;
+    }
+
+    private static Version NormalizeVersion(Version version)
+    {
+        var major = Math.Max(0, version.Major);
+        var minor = Math.Max(0, version.Minor);
+        var build = Math.Max(0, version.Build >= 0 ? version.Build : 0);
+        var revision = Math.Max(0, version.Revision >= 0 ? version.Revision : 0);
+        return revision > 0
+            ? new Version(major, minor, build, revision)
+            : new Version(major, minor, build);
+    }
+
+    private static string FormatVersionText(Version version)
+    {
+        return version.Revision > 0
+            ? version.ToString(4)
+            : version.ToString(3);
+    }
+
+    private static string Truncate(string value, int maxLength)
+    {
+        if (string.IsNullOrEmpty(value) || value.Length <= maxLength)
+        {
+            return value;
+        }
+
+        return value[..maxLength];
+    }
+}
diff --git a/LanMountainDesktop/Services/Settings/SettingsDomainServices.cs b/LanMountainDesktop/Services/Settings/SettingsDomainServices.cs
index c2547b3..35f2784 100644
--- a/LanMountainDesktop/Services/Settings/SettingsDomainServices.cs
+++ b/LanMountainDesktop/Services/Settings/SettingsDomainServices.cs
@@ -751,7 +751,8 @@ internal sealed class PrivacySettingsService : IPrivacySettingsService
 internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposable
 {
     private readonly ISettingsService _settingsService;
-    private readonly GitHubReleaseUpdateService _releaseUpdateService = new("wwiinnddyy", "LanMountainDesktop");
+    private readonly GitHubReleaseUpdateService _githubReleaseUpdateService = new("wwiinnddyy", "LanMountainDesktop");
+    private readonly PdcReleaseUpdateService _pdcReleaseUpdateService = new();
 
     public UpdateSettingsService(ISettingsService settingsService)
     {
@@ -830,7 +831,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         bool includePrerelease,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.CheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: false, cancellationToken);
     }
 
     public Task<UpdateCheckResult> ForceCheckForUpdatesAsync(
@@ -838,7 +839,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         bool includePrerelease,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.ForceCheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: true, cancellationToken);
     }
 
     public Task<UpdateDownloadResult> DownloadAssetAsync(
@@ -849,7 +850,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         IProgress<double>? progress = null,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.DownloadAssetAsync(
+        return _githubReleaseUpdateService.DownloadAssetAsync(
             asset,
             destinationFilePath,
             downloadSource,
@@ -866,7 +867,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         IProgress<double>? progress = null,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.RedownloadAssetAsync(
+        return _githubReleaseUpdateService.RedownloadAssetAsync(
             asset,
             destinationFilePath,
             downloadSource,
@@ -877,7 +878,36 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
 
     public void Dispose()
     {
-        _releaseUpdateService.Dispose();
+        _githubReleaseUpdateService.Dispose();
+        _pdcReleaseUpdateService.Dispose();
+    }
+
+    private async Task<UpdateCheckResult> CheckForUpdatesCoreAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        bool isForce,
+        CancellationToken cancellationToken)
+    {
+        var source = UpdateSettingsValues.NormalizeDownloadSource(_settingsService.Load().UpdateDownloadSource);
+        if (string.Equals(source, UpdateSettingsValues.DownloadSourcePdc, StringComparison.OrdinalIgnoreCase))
+        {
+            var pdcResult = isForce
+                ? await _pdcReleaseUpdateService.ForceCheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken)
+                : await _pdcReleaseUpdateService.CheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
+
+            if (pdcResult.Success)
+            {
+                return pdcResult;
+            }
+
+            AppLogger.Warn(
+                "UpdateSettings",
+                $"PDC update check failed and will fallback to GitHub. Error: {pdcResult.ErrorMessage}");
+        }
+
+        return isForce
+            ? await _githubReleaseUpdateService.ForceCheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken)
+            : await _githubReleaseUpdateService.CheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
     }
 }
 
diff --git a/LanMountainDesktop/Services/UpdateSettingsValues.cs b/LanMountainDesktop/Services/UpdateSettingsValues.cs
index bb5e7f4..0a5af37 100644
--- a/LanMountainDesktop/Services/UpdateSettingsValues.cs
+++ b/LanMountainDesktop/Services/UpdateSettingsValues.cs
@@ -11,6 +11,7 @@ public static class UpdateSettingsValues
     public const string ModeDownloadThenConfirm = "download_then_confirm";
     public const string ModeSilentOnExit = "silent_on_exit";
 
+    public const string DownloadSourcePdc = "pdc";
     public const string DownloadSourceGitHub = "github";
     public const string DownloadSourceGhProxy = "gh-proxy";
 
@@ -51,9 +52,23 @@ public static class UpdateSettingsValues
 
     public static string NormalizeDownloadSource(string? value)
     {
-        return string.Equals(value, DownloadSourceGhProxy, StringComparison.OrdinalIgnoreCase)
-            ? DownloadSourceGhProxy
-            : DownloadSourceGitHub;
+        if (string.Equals(value, DownloadSourcePdc, StringComparison.OrdinalIgnoreCase))
+        {
+            return DownloadSourcePdc;
+        }
+
+        if (string.Equals(value, DownloadSourceGhProxy, StringComparison.OrdinalIgnoreCase))
+        {
+            return DownloadSourceGhProxy;
+        }
+
+        if (string.Equals(value, DownloadSourceGitHub, StringComparison.OrdinalIgnoreCase))
+        {
+            return DownloadSourceGitHub;
+        }
+
+        // Default to PDC. Runtime will fallback to GitHub if PDC is unavailable.
+        return DownloadSourcePdc;
     }
 
     public static int NormalizeDownloadThreads(int value)
diff --git a/LanMountainDesktop/Services/UpdateWorkflowService.cs b/LanMountainDesktop/Services/UpdateWorkflowService.cs
index d8ecb34..42b2154 100644
--- a/LanMountainDesktop/Services/UpdateWorkflowService.cs
+++ b/LanMountainDesktop/Services/UpdateWorkflowService.cs
@@ -5,6 +5,7 @@ using System.Diagnostics;
 using System.Globalization;
 using System.IO;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using LanMountainDesktop.PluginSdk;
@@ -52,7 +53,9 @@ public sealed class UpdateWorkflowService
     private const string LauncherDirectoryName = ".launcher";
     private const string UpdateDirectoryName = "update";
     private const string IncomingDirectoryName = "incoming";
-    private const string VelopackReleasesFileName = "releases.win.json";
+    private const string SignedFileMapName = "files.json";
+    private const string SignedFileMapSignatureName = "files.json.sig";
+    private const string UpdateArchiveName = "update.zip";
 
     public UpdateWorkflowService(ISettingsFacadeService settingsFacade)
     {
@@ -79,7 +82,7 @@ public sealed class UpdateWorkflowService
     }
 
     /// <summary>
-    /// Checks whether a GitHub Release contains Velopack assets needed for incremental updates.
+    /// Checks whether a GitHub Release contains signed file-map assets needed for incremental updates.
     /// </summary>
     public static bool IsDeltaUpdateAvailable(GitHubReleaseInfo release)
     {
@@ -88,13 +91,11 @@ public sealed class UpdateWorkflowService
             return false;
         }
 
-        var hasFeed = release.Assets.Any(a => string.Equals(a.Name, VelopackReleasesFileName, StringComparison.OrdinalIgnoreCase));
-        var hasFull = release.Assets.Any(a => a.Name.EndsWith("-full.nupkg", StringComparison.OrdinalIgnoreCase));
-        return hasFeed && hasFull;
+        return TryResolveDeltaAssets(release.Assets, out _, out _, out _);
     }
 
     /// <summary>
-    /// Downloads Velopack release feed and package files to the Launcher's incoming directory.
+    /// Downloads signed file-map assets to the Launcher's incoming directory.
     /// </summary>
     public async Task<UpdateDownloadResult> DownloadDeltaUpdateAsync(
         UpdateCheckResult checkResult,
@@ -108,11 +109,9 @@ public sealed class UpdateWorkflowService
             return new UpdateDownloadResult(false, null, "No update available for delta download.");
         }
 
-        var releasesFeedAsset = checkResult.Release.Assets.FirstOrDefault(a =>
-            string.Equals(a.Name, VelopackReleasesFileName, StringComparison.OrdinalIgnoreCase));
-        if (releasesFeedAsset is null)
+        if (!TryResolveDeltaAssets(checkResult.Release.Assets, out var manifestAsset, out var signatureAsset, out var archiveAsset))
         {
-            return new UpdateDownloadResult(false, null, "Release does not contain releases.win.json.");
+            return new UpdateDownloadResult(false, null, "Release does not contain compatible signed file-map assets.");
         }
 
         var incomingDir = GetLauncherIncomingDirectory();
@@ -130,29 +129,19 @@ public sealed class UpdateWorkflowService
         var downloadSource = state.UpdateDownloadSource;
         var downloadThreads = state.UpdateDownloadThreads;
 
-        var latestVersionText = checkResult.LatestVersionText.Trim();
-        var targetPackages = checkResult.Release.Assets
-            .Where(a => a.Name.EndsWith(".nupkg", StringComparison.OrdinalIgnoreCase))
-            .Where(a => a.Name.Contains(latestVersionText, StringComparison.OrdinalIgnoreCase))
-            .Where(a =>
-                a.Name.EndsWith("-full.nupkg", StringComparison.OrdinalIgnoreCase) ||
-                a.Name.EndsWith("-delta.nupkg", StringComparison.OrdinalIgnoreCase))
-            .ToList();
-
-        if (targetPackages.Count == 0)
+        var requiredAssets = new List<(GitHubReleaseAsset Asset, string DestinationFileName)>
         {
-            return new UpdateDownloadResult(false, null, "No Velopack nupkg asset found for the target version.");
-        }
-
-        var requiredAssets = new List<GitHubReleaseAsset> { releasesFeedAsset };
-        requiredAssets.AddRange(targetPackages);
+            (manifestAsset, SignedFileMapName),
+            (signatureAsset, SignedFileMapSignatureName),
+            (archiveAsset, UpdateArchiveName)
+        };
 
         var totalAssets = requiredAssets.Count;
         var completedAssets = 0;
 
-        foreach (var asset in requiredAssets)
+        foreach (var (asset, destinationFileName) in requiredAssets)
         {
-            var destinationPath = Path.Combine(incomingDir, asset.Name);
+            var destinationPath = Path.Combine(incomingDir, destinationFileName);
 
             // Skip if already downloaded and file exists
             if (File.Exists(destinationPath))
@@ -160,7 +149,7 @@ public sealed class UpdateWorkflowService
                 var existingHash = await GitHubReleaseUpdateService.ComputeFileSha256Async(destinationPath, cancellationToken);
                 if (asset.Sha256 is not null && string.Equals(existingHash, asset.Sha256, StringComparison.OrdinalIgnoreCase))
                 {
-                    AppLogger.Info("UpdateWorkflow", $"Velopack asset {asset.Name} already downloaded with matching hash, skipping.");
+                    AppLogger.Info("UpdateWorkflow", $"Update asset {asset.Name} already downloaded with matching hash, skipping.");
                     completedAssets++;
                     progress?.Report((double)completedAssets / totalAssets);
                     continue;
@@ -184,21 +173,21 @@ public sealed class UpdateWorkflowService
             if (!result.Success)
             {
                 // Clean up partially downloaded files
-                foreach (var file in requiredAssets.Select(a => a.Name))
+                foreach (var file in requiredAssets.Select(a => a.DestinationFileName))
                 {
                     try { File.Delete(Path.Combine(incomingDir, file)); } catch { }
                 }
-                return new UpdateDownloadResult(false, null, $"Failed to download Velopack asset {asset.Name}: {result.ErrorMessage}");
+                return new UpdateDownloadResult(false, null, $"Failed to download update asset {asset.Name}: {result.ErrorMessage}");
             }
 
             completedAssets++;
             progress?.Report((double)completedAssets / totalAssets);
         }
 
-        // Save state indicating a Velopack update is pending.
+        // Save state indicating a signed file-map update is pending.
         SaveState(state with
         {
-            PendingUpdateInstallerPath = Path.Combine(incomingDir, VelopackReleasesFileName),
+            PendingUpdateInstallerPath = Path.Combine(incomingDir, SignedFileMapName),
             PendingUpdateVersion = checkResult.LatestVersionText,
             PendingUpdatePublishedAtUtcMs = checkResult.Release.PublishedAt == DateTimeOffset.MinValue
                 ? null
@@ -207,9 +196,9 @@ public sealed class UpdateWorkflowService
             PendingUpdateSha256 = null
         });
 
-        AppLogger.Info("UpdateWorkflow", $"Velopack update payload downloaded to {incomingDir}. Will be applied by Launcher on next startup.");
+        AppLogger.Info("UpdateWorkflow", $"Signed file-map update payload downloaded to {incomingDir}. Will be applied by Launcher on next startup.");
 
-        return new UpdateDownloadResult(true, Path.Combine(incomingDir, VelopackReleasesFileName), null);
+        return new UpdateDownloadResult(true, Path.Combine(incomingDir, SignedFileMapName), null);
     }
 
     /// <summary>
@@ -224,11 +213,71 @@ public sealed class UpdateWorkflowService
             return false;
         }
 
-        // Velopack updates are identified by the releases feed path.
-        return pendingPath.EndsWith(VelopackReleasesFileName, StringComparison.OrdinalIgnoreCase)
+        // Incoming payload updates are identified by files.json or incoming directory path.
+        return pendingPath.EndsWith(SignedFileMapName, StringComparison.OrdinalIgnoreCase)
             || pendingPath.Contains(IncomingDirectoryName, StringComparison.OrdinalIgnoreCase);
     }
 
+    private static bool TryResolveDeltaAssets(
+        IReadOnlyList<GitHubReleaseAsset> assets,
+        out GitHubReleaseAsset manifestAsset,
+        out GitHubReleaseAsset signatureAsset,
+        out GitHubReleaseAsset archiveAsset)
+    {
+        manifestAsset = default!;
+        signatureAsset = default!;
+        archiveAsset = default!;
+
+        if (assets is null || assets.Count == 0)
+        {
+            return false;
+        }
+
+        var platformSuffix = GetPlatformAssetSuffix();
+        var platformManifest = $"files-{platformSuffix}.json";
+        var platformSignature = $"files-{platformSuffix}.json.sig";
+        var platformArchive = $"update-{platformSuffix}.zip";
+
+        var manifestCandidate = FindAsset(assets, platformManifest) ?? FindAsset(assets, SignedFileMapName);
+        var signatureCandidate = FindAsset(assets, platformSignature) ?? FindAsset(assets, SignedFileMapSignatureName);
+        var archiveCandidate = FindAsset(assets, platformArchive) ?? FindAsset(assets, UpdateArchiveName);
+        if (manifestCandidate is null || signatureCandidate is null || archiveCandidate is null)
+        {
+            return false;
+        }
+
+        manifestAsset = manifestCandidate;
+        signatureAsset = signatureCandidate;
+        archiveAsset = archiveCandidate;
+        return true;
+    }
+
+    private static GitHubReleaseAsset? FindAsset(IReadOnlyList<GitHubReleaseAsset> assets, string name)
+    {
+        return assets.FirstOrDefault(a => string.Equals(a.Name, name, StringComparison.OrdinalIgnoreCase));
+    }
+
+    private static string GetPlatformAssetSuffix()
+    {
+        var os = OperatingSystem.IsWindows()
+            ? "windows"
+            : OperatingSystem.IsLinux()
+                ? "linux"
+                : OperatingSystem.IsMacOS()
+                    ? "macos"
+                    : "unknown";
+
+        var arch = RuntimeInformation.OSArchitecture switch
+        {
+            Architecture.X86 => "x86",
+            Architecture.Arm => "arm",
+            Architecture.Arm64 => "arm64",
+            _ => "x64"
+        };
+
+        return $"{os}-{arch}";
+    }
+
     public UpdatePendingInfo? GetPendingUpdate()
     {
         var state = _settingsFacade.Update.Get();
diff --git a/LanMountainDesktop/ViewModels/SettingsViewModels.cs b/LanMountainDesktop/ViewModels/SettingsViewModels.cs
index 3088891..0104a82 100644
--- a/LanMountainDesktop/ViewModels/SettingsViewModels.cs
+++ b/LanMountainDesktop/ViewModels/SettingsViewModels.cs
@@ -1496,7 +1496,7 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
     private string _selectedUpdateChannelValue = UpdateSettingsValues.ChannelStable;
 
     [ObservableProperty]
-    private string _selectedUpdateSourceValue = UpdateSettingsValues.DownloadSourceGitHub;
+    private string _selectedUpdateSourceValue = UpdateSettingsValues.DownloadSourcePdc;
 
     [ObservableProperty]
     private string _selectedUpdateModeValue = UpdateSettingsValues.ModeDownloadThenConfirm;
@@ -1630,6 +1630,9 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
     [ObservableProperty]
     private string _previewChannelText = string.Empty;
 
+    [ObservableProperty]
+    private string _pdcSourceText = string.Empty;
+
     [ObservableProperty]
     private string _gitHubSourceText = string.Empty;
 
@@ -1666,6 +1669,9 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
     public bool IsPreviewChannelSelected =>
         string.Equals(SelectedUpdateChannelValue, UpdateSettingsValues.ChannelPreview, StringComparison.OrdinalIgnoreCase);
 
+    public bool IsPdcSourceSelected =>
+        string.Equals(SelectedUpdateSourceValue, UpdateSettingsValues.DownloadSourcePdc, StringComparison.OrdinalIgnoreCase);
+
     public bool IsGitHubSourceSelected =>
         string.Equals(SelectedUpdateSourceValue, UpdateSettingsValues.DownloadSourceGitHub, StringComparison.OrdinalIgnoreCase);
 
@@ -1858,6 +1864,12 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
         SelectedUpdateChannelValue = UpdateSettingsValues.ChannelPreview;
     }
 
+    [RelayCommand]
+    private void SelectPdcSource()
+    {
+        SelectedUpdateSourceValue = UpdateSettingsValues.DownloadSourcePdc;
+    }
+
     [RelayCommand]
     private void SelectGitHubSource()
     {
@@ -1929,8 +1941,8 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
             DownloadProgressValue = 0;
             DownloadProgressText = L("settings.update.download_progress_idle", "Download progress: -");
             UpdateStatus = isForce
-                ? L("settings.update.status_force_checking", "Force checking GitHub releases...")
-                : L("settings.update.status_checking", "Checking GitHub releases...");
+                ? L("settings.update.status_force_checking", "Force checking update source...")
+                : L("settings.update.status_checking", "Checking update source...");
 
             var result = await _updateWorkflowService.CheckForUpdatesAsync(_currentVersion, isForce);
             _lastCheckResult = result.Success ? result : null;
@@ -2100,7 +2112,7 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
         DownloadThreadsLabel = L("settings.update.download_threads_label", "Download Threads");
         DownloadThreadsDescription = L("settings.update.download_threads_desc", "Choose how many parallel download threads are used for application updates.");
         ForceCheckUpdateLabel = L("settings.update.force_check_label", "Force Check Update");
-        ForceCheckUpdateDescription = L("settings.update.force_check_desc", "Force check for updates from GitHub, ignoring version comparison.");
+        ForceCheckUpdateDescription = L("settings.update.force_check_desc", "Force check for updates, ignoring version comparison.");
         CheckForUpdatesButtonText = L("settings.update.check_button", "Check for Updates");
         DownloadButtonText = L("settings.update.download_install_button", "Download & Install");
         InstallNowButtonText = L("settings.update.install_now_button", "Install Now");
@@ -2112,6 +2124,7 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
         UpdateTypeLabel = L("settings.update.type_label", "Update Type");
         StableChannelText = L("settings.update.channel_stable", "Stable");
         PreviewChannelText = L("settings.update.channel_preview", "Preview");
+        PdcSourceText = L("settings.update.source_pdc", "PDC");
         GitHubSourceText = L("settings.update.source_github", "GitHub");
         GhProxySourceText = L("settings.update.source_ghproxy", "gh-proxy");
         ManualModeText = L("settings.update.mode_manual", "Manual Update");
@@ -2309,6 +2322,9 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
     {
         return UpdateSettingsValues.NormalizeDownloadSource(value) switch
         {
+            UpdateSettingsValues.DownloadSourcePdc => L(
+                "settings.update.source_pdc_desc",
+                "Prefer PDC metadata and distribution endpoints, then automatically fallback to GitHub."),
             UpdateSettingsValues.DownloadSourceGhProxy => L(
                 "settings.update.source_ghproxy_desc",
                 "Use the gh-proxy mirror when downloading GitHub release assets."),
@@ -2360,6 +2376,7 @@ public sealed partial class UpdateSettingsPageViewModel : ViewModelBase
     {
         return
         [
+            new SelectionOption(UpdateSettingsValues.DownloadSourcePdc, PdcSourceText),
             new SelectionOption(UpdateSettingsValues.DownloadSourceGitHub, GitHubSourceText),
             new SelectionOption(UpdateSettingsValues.DownloadSourceGhProxy, GhProxySourceText)
         ];
diff --git a/phainon.yml b/phainon.yml
new file mode 100644
index 0000000..f4aa909
--- /dev/null
+++ b/phainon.yml
@@ -0,0 +1,29 @@
+# Phainon Distribution Center (PDC) publish configuration
+# This file is intentionally conservative: Launcher remains installer/rollback authority.
+name: "LanMountainDesktop"
+
+components:
+  app:
+    allowDiffUpdate: true
+    root: "app-$(version)/"
+    includes:
+      - "**"
+  launcher:
+    root: ""
+    includes:
+      - "**"
+    excludes:
+      - "app-*/**"
+      - ".launcher/update/incoming/**"
+      - "files.json"
+      - "files.json.sig"
+      - "update.zip"
+
+variables:
+  number: 0
+
+# Replace these roots in CI/CD or environment-specific templates when enabling PDCC publish.
+fileRepoRoot: "https://example.invalid/lanmountain/distribution-v1/repo/"
+archiveRoot: "https://example.invalid/lanmountain/distribution-v1/$(primaryVersion)/$(version)/"
+bucketKeyRoot: "lanmountain/distribution-v1/repo/"
+archiveBucketKeyRoot: "lanmountain/distribution-v1/$(primaryVersion)/$(version)/"
diff --git a/scripts/Generate-DeltaPackage.ps1 b/scripts/Generate-DeltaPackage.ps1
index 34f4919..5bb7705 100644
--- a/scripts/Generate-DeltaPackage.ps1
+++ b/scripts/Generate-DeltaPackage.ps1
@@ -1,105 +1,152 @@
-# Generate-DeltaPackage.ps1
-# 生成增量更新包 (delta.zip + files.json)
-
 param(
-    [Parameter(Mandatory=$true)]
+    [Parameter(Mandatory = $true)]
     [string]$PreviousVersion,
-    
-    [Parameter(Mandatory=$true)]
+
+    [Parameter(Mandatory = $true)]
     [string]$CurrentVersion,
-    
-    [Parameter(Mandatory=$true)]
+
+    [Parameter(Mandatory = $true)]
     [string]$PreviousDir,
-    
-    [Parameter(Mandatory=$true)]
+
+    [Parameter(Mandatory = $true)]
     [string]$CurrentDir,
-    
-    [Parameter(Mandatory=$true)]
+
+    [Parameter(Mandatory = $true)]
     [string]$OutputDir
 )
 
 $ErrorActionPreference = "Stop"
 
-Write-Host "=== 生成增量更新包 ===" -ForegroundColor Cyan
-Write-Host "从版本: $PreviousVersion"
-Write-Host "到版本: $CurrentVersion"
-Write-Host "上一版本目录: $PreviousDir"
-Write-Host "当前版本目录: $CurrentDir"
-Write-Host "输出目录: $OutputDir"
-Write-Host ""
+Add-Type -AssemblyName System.IO.Compression
+Add-Type -AssemblyName System.IO.Compression.FileSystem
 
-# 确保输出目录存在
-New-Item -ItemType Directory -Force -Path $OutputDir | Out-Null
+function Get-NormalizedRelativePath {
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]$RootDir,
 
-# 计算文件 SHA256
-function Get-FileSha256 {
-    param([string]$Path)
-    $hash = Get-FileHash -Path $Path -Algorithm SHA256
-    return $hash.Hash.ToLower()
+        [Parameter(Mandatory = $true)]
+        [string]$FullPath
+    )
+
+    $root = [System.IO.Path]::GetFullPath($RootDir)
+    $path = [System.IO.Path]::GetFullPath($FullPath)
+
+    if (-not $root.EndsWith([System.IO.Path]::DirectorySeparatorChar.ToString()) -and
+        -not $root.EndsWith([System.IO.Path]::AltDirectorySeparatorChar.ToString())) {
+        $root += [System.IO.Path]::DirectorySeparatorChar
+    }
+
+    $rootUri = [System.Uri]$root
+    $pathUri = [System.Uri]$path
+    $relative = [System.Uri]::UnescapeDataString($rootUri.MakeRelativeUri($pathUri).ToString())
+
+    return $relative.Replace('\', '/')
+}
+
+function Get-FileSha256Hex {
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]$Path
+    )
+
+    return (Get-FileHash -LiteralPath $Path -Algorithm SHA256).Hash.ToLowerInvariant()
 }
 
-# 获取目录中所有文件的相对路径和哈希
 function Get-FileManifest {
-    param([string]$RootDir)
-    
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]$RootDir
+    )
+
+    if (-not (Test-Path -LiteralPath $RootDir)) {
+        throw "Directory does not exist: $RootDir"
+    }
+
+    $resolvedRoot = (Resolve-Path -LiteralPath $RootDir).Path
     $manifest = @{}
-    $files = Get-ChildItem -Path $RootDir -Recurse -File
-    
+    $files = Get-ChildItem -LiteralPath $resolvedRoot -Recurse -File
+
     foreach ($file in $files) {
-        $relativePath = $file.FullName.Substring($RootDir.Length).TrimStart('\', '/')
-        $relativePath = $relativePath.Replace('\', '/')
-        
-        $manifest[$relativePath] = @{
+        $relativePath = Get-NormalizedRelativePath -RootDir $resolvedRoot -FullPath $file.FullName
+        $manifest[$relativePath] = [ordered]@{
             Path = $relativePath
-            Sha256 = Get-FileSha256 -Path $file.FullName
-            Size = $file.Length
+            Sha256 = Get-FileSha256Hex -Path $file.FullName
+            Size = [long]$file.Length
         }
     }
-    
+
     return $manifest
 }
 
-Write-Host "扫描上一版本文件..." -ForegroundColor Yellow
-Write-Host "  目录: $PreviousDir" -ForegroundColor Gray
-if (-not (Test-Path $PreviousDir)) {
-    throw "Previous directory does not exist: $PreviousDir"
+function New-DeltaArchive {
+    param(
+        [Parameter(Mandatory = $true)]
+        [string]$ZipPath,
+
+        [Parameter(Mandatory = $true)]
+        [string]$CurrentRoot,
+
+        [Parameter(Mandatory = $true)]
+        [object[]]$ChangedFiles
+    )
+
+    if (Test-Path -LiteralPath $ZipPath) {
+        Remove-Item -LiteralPath $ZipPath -Force
+    }
+
+    $zip = [System.IO.Compression.ZipFile]::Open($ZipPath, [System.IO.Compression.ZipArchiveMode]::Create)
+    try {
+        foreach ($file in $ChangedFiles) {
+            $sourcePath = Join-Path $CurrentRoot $file.Path
+            if (-not (Test-Path -LiteralPath $sourcePath)) {
+                throw "Changed file was not found while building archive: $sourcePath"
+            }
+
+            [System.IO.Compression.ZipFileExtensions]::CreateEntryFromFile(
+                $zip,
+                $sourcePath,
+                $file.Path,
+                [System.IO.Compression.CompressionLevel]::Optimal
+            ) | Out-Null
+        }
+    }
+    finally {
+        $zip.Dispose()
+    }
 }
+
+Write-Host "Generating incremental package..."
+Write-Host "From: $PreviousVersion"
+Write-Host "To:   $CurrentVersion"
+Write-Host "Prev: $PreviousDir"
+Write-Host "Curr: $CurrentDir"
+Write-Host "Out:  $OutputDir"
+
+New-Item -ItemType Directory -Path $OutputDir -Force | Out-Null
+
 $previousManifest = Get-FileManifest -RootDir $PreviousDir
-Write-Host "  找到 $($previousManifest.Count) 个文件" -ForegroundColor Gray
-
-Write-Host "扫描当前版本文件..." -ForegroundColor Yellow
-Write-Host "  目录: $CurrentDir" -ForegroundColor Gray
-if (-not (Test-Path $CurrentDir)) {
-    throw "Current directory does not exist: $CurrentDir"
-}
 $currentManifest = Get-FileManifest -RootDir $CurrentDir
-Write-Host "  找到 $($currentManifest.Count) 个文件" -ForegroundColor Gray
 
-# 分析文件变更
 $changedFiles = @()
 $reusedFiles = @()
 $deletedFiles = @()
 
-Write-Host "分析文件变更..." -ForegroundColor Yellow
-
-# 检查新增和修改的文件
-foreach ($path in $currentManifest.Keys) {
+foreach ($path in ($currentManifest.Keys | Sort-Object)) {
     $currentFile = $currentManifest[$path]
-    
+
     if ($previousManifest.ContainsKey($path)) {
         $previousFile = $previousManifest[$path]
-        
         if ($currentFile.Sha256 -eq $previousFile.Sha256) {
-            # 文件未变更,可以复用
-            $reusedFiles += @{
+            $reusedFiles += [ordered]@{
                 Path = $path
                 Action = "reuse"
                 Sha256 = $currentFile.Sha256
                 Size = $currentFile.Size
             }
-        } else {
-            # 文件已修改
-            $changedFiles += @{
+        }
+        else {
+            $changedFiles += [ordered]@{
                 Path = $path
                 Action = "replace"
                 Sha256 = $currentFile.Sha256
@@ -107,9 +154,9 @@ foreach ($path in $currentManifest.Keys) {
                 ArchivePath = $path
             }
         }
-    } else {
-        # 新增文件
-        $changedFiles += @{
+    }
+    else {
+        $changedFiles += [ordered]@{
             Path = $path
             Action = "add"
             Sha256 = $currentFile.Sha256
@@ -119,104 +166,51 @@ foreach ($path in $currentManifest.Keys) {
     }
 }
 
-# 检查删除的文件
-foreach ($path in $previousManifest.Keys) {
+foreach ($path in ($previousManifest.Keys | Sort-Object)) {
     if (-not $currentManifest.ContainsKey($path)) {
-        $deletedFiles += @{
+        $deletedFiles += [ordered]@{
             Path = $path
             Action = "delete"
         }
     }
 }
 
-Write-Host "变更统计:" -ForegroundColor Green
-Write-Host "  新增/修改: $($changedFiles.Count) 个文件"
-Write-Host "  复用: $($reusedFiles.Count) 个文件"
-Write-Host "  删除: $($deletedFiles.Count) 个文件"
-Write-Host ""
+Write-Host "Changed: $($changedFiles.Count)"
+Write-Host "Reused:  $($reusedFiles.Count)"
+Write-Host "Deleted: $($deletedFiles.Count)"
 
-# 显示前10个变更的文件（用于调试）
-if ($changedFiles.Count -gt 0) {
-    Write-Host "变更的文件示例:" -ForegroundColor Cyan
-    $changedFiles | Select-Object -First 10 | ForEach-Object {
-        Write-Host "  [$($_.Action)] $($_.Path)" -ForegroundColor Gray
-    }
-    if ($changedFiles.Count -gt 10) {
-        Write-Host "  ... 还有 $($changedFiles.Count - 10) 个文件" -ForegroundColor Gray
-    }
-    Write-Host ""
-}
-
-# 创建临时目录用于打包
-$tempDir = Join-Path $OutputDir "temp_delta"
-if (Test-Path $tempDir) {
-    Remove-Item -Path $tempDir -Recurse -Force
-}
-New-Item -ItemType Directory -Force -Path $tempDir | Out-Null
-
-# 复制变更的文件到临时目录
-Write-Host "复制变更文件..." -ForegroundColor Yellow
-foreach ($file in $changedFiles) {
-    $sourcePath = Join-Path $CurrentDir $file.Path
-    $destPath = Join-Path $tempDir $file.Path
-    $destDir = Split-Path -Parent $destPath
-    
-    if (-not (Test-Path $destDir)) {
-        New-Item -ItemType Directory -Force -Path $destDir | Out-Null
-    }
-    
-    Copy-Item -Path $sourcePath -Destination $destPath -Force
-}
-
-# 创建 update.zip (Launcher 期望的文件名)
+$resolvedCurrentDir = (Resolve-Path -LiteralPath $CurrentDir).Path
 $updateZipPath = Join-Path $OutputDir "update.zip"
-Write-Host "创建增量包: $updateZipPath" -ForegroundColor Yellow
+New-DeltaArchive -ZipPath $updateZipPath -CurrentRoot $resolvedCurrentDir -ChangedFiles $changedFiles
 
-if (Test-Path $updateZipPath) {
-    Remove-Item -Path $updateZipPath -Force
-}
+$deltaZipPath = Join-Path $OutputDir ("delta-{0}-to-{1}.zip" -f $PreviousVersion, $CurrentVersion)
+Copy-Item -LiteralPath $updateZipPath -Destination $deltaZipPath -Force
 
-Compress-Archive -Path "$tempDir\*" -DestinationPath $updateZipPath -CompressionLevel Optimal
-
-# 同时创建带版本号的副本（用于发布到 GitHub Release）
-$deltaZipPath = Join-Path $OutputDir "delta-$PreviousVersion-to-$CurrentVersion.zip"
-Write-Host "创建带版本号的副本: $deltaZipPath" -ForegroundColor Yellow
-if (Test-Path $deltaZipPath) {
-    Remove-Item -Path $deltaZipPath -Force
-}
-Copy-Item -Path $updateZipPath -Destination $deltaZipPath -Force
-
-# 清理临时目录
-Remove-Item -Path $tempDir -Recurse -Force
-
-# 生成 files.json (Launcher 期望的文件名)
-$filesJson = @{
+$allEntries = @($changedFiles + $reusedFiles + $deletedFiles)
+$filesJson = [ordered]@{
     FromVersion = $PreviousVersion
     ToVersion = $CurrentVersion
-    GeneratedAt = (Get-Date).ToUniversalTime().ToString("o")
-    Files = @($changedFiles + $reusedFiles + $deletedFiles)
+    GeneratedAt = [DateTimeOffset]::UtcNow.ToString("o")
+    Files = $allEntries
 }
 
+$jsonText = $filesJson | ConvertTo-Json -Depth 10
+$utf8NoBom = New-Object System.Text.UTF8Encoding($false)
+
 $filesJsonPath = Join-Path $OutputDir "files.json"
-Write-Host "生成文件清单: $filesJsonPath" -ForegroundColor Yellow
+[System.IO.File]::WriteAllText($filesJsonPath, $jsonText, $utf8NoBom)
 
-$filesJson | ConvertTo-Json -Depth 10 | Set-Content -Path $filesJsonPath -Encoding UTF8
+$versionedFilesJsonPath = Join-Path $OutputDir ("files-{0}.json" -f $CurrentVersion)
+Copy-Item -LiteralPath $filesJsonPath -Destination $versionedFilesJsonPath -Force
 
-# 同时创建带版本号的副本（用于发布到 GitHub Release）
-$versionedFilesJsonPath = Join-Path $OutputDir "files-$CurrentVersion.json"
-Write-Host "创建带版本号的副本: $versionedFilesJsonPath" -ForegroundColor Yellow
-Copy-Item -Path $filesJsonPath -Destination $versionedFilesJsonPath -Force
-
-# 计算增量包大小
-$updateSize = (Get-Item $updateZipPath).Length
-$updateSizeMB = [math]::Round($updateSize / 1MB, 2)
+$updateSizeBytes = (Get-Item -LiteralPath $updateZipPath).Length
+$updateSizeMb = [Math]::Round($updateSizeBytes / 1MB, 2)
 
 Write-Host ""
-Write-Host "=== 完成 ===" -ForegroundColor Green
-Write-Host "增量包大小: $updateSizeMB MB"
-Write-Host "输出文件 (Launcher 使用):"
-Write-Host "  - $updateZipPath"
-Write-Host "  - $filesJsonPath"
-Write-Host "输出文件 (GitHub Release 发布):"
-Write-Host "  - $deltaZipPath"
-Write-Host "  - $versionedFilesJsonPath"
+Write-Host "Done."
+Write-Host "update.zip size: $updateSizeMb MB"
+Write-Host "Generated:"
+Write-Host "  $updateZipPath"
+Write-Host "  $filesJsonPath"
+Write-Host "  $deltaZipPath"
+Write-Host "  $versionedFilesJsonPath"
diff --git a/scripts/Sign-FileMap.ps1 b/scripts/Sign-FileMap.ps1
index 4747fb7..fe92155 100644
--- a/scripts/Sign-FileMap.ps1
+++ b/scripts/Sign-FileMap.ps1
@@ -1,65 +1,56 @@
-# Sign-FileMap.ps1
-# 对 files.json 进行 RSA 签名
-
 param(
-    [Parameter(Mandatory=$true)]
+    [Parameter(Mandatory = $true)]
     [string]$FilesJsonPath,
-    
-    [Parameter(Mandatory=$true)]
+
+    [Parameter(Mandatory = $true)]
     [string]$PrivateKeyPath,
-    
-    [Parameter(Mandatory=$false)]
+
+    [Parameter(Mandatory = $false)]
     [string]$OutputPath
 )
 
 $ErrorActionPreference = "Stop"
 
-Write-Host "=== 签名文件清单 ===" -ForegroundColor Cyan
-Write-Host "文件清单: $FilesJsonPath"
-Write-Host "私钥: $PrivateKeyPath"
-Write-Host ""
-
-# 检查文件是否存在
-if (-not (Test-Path $FilesJsonPath)) {
-    Write-Error "文件清单不存在: $FilesJsonPath"
-    exit 1
+if ($PSVersionTable.PSVersion.Major -lt 7) {
+    throw "Sign-FileMap.ps1 requires PowerShell 7 or newer."
 }
 
-if (-not (Test-Path $PrivateKeyPath)) {
-    Write-Error "私钥文件不存在: $PrivateKeyPath"
-    exit 1
+if (-not (Test-Path -LiteralPath $FilesJsonPath)) {
+    throw "Manifest file not found: $FilesJsonPath"
+}
+
+if (-not (Test-Path -LiteralPath $PrivateKeyPath)) {
+    throw "Private key file not found: $PrivateKeyPath"
 }
 
-# 确定输出路径
 if ([string]::IsNullOrWhiteSpace($OutputPath)) {
     $OutputPath = "$FilesJsonPath.sig"
 }
 
-# 读取文件内容
-$jsonBytes = [System.IO.File]::ReadAllBytes($FilesJsonPath)
+$resolvedManifestPath = (Resolve-Path -LiteralPath $FilesJsonPath).Path
+$manifestBytes = [System.IO.File]::ReadAllBytes($resolvedManifestPath)
 
-# 读取私钥
-$privateKeyPem = Get-Content -Path $PrivateKeyPath -Raw
-
-# 使用 .NET 进行 RSA 签名
-Add-Type -AssemblyName System.Security.Cryptography
+$privateKeyPem = Get-Content -LiteralPath $PrivateKeyPath -Raw
+if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
+    throw "Private key PEM is empty: $PrivateKeyPath"
+}
 
 $rsa = [System.Security.Cryptography.RSA]::Create()
-$rsa.ImportFromPem($privateKeyPem)
+try {
+    $rsa.ImportFromPem($privateKeyPem)
+    $signatureBytes = $rsa.SignData(
+        $manifestBytes,
+        [System.Security.Cryptography.HashAlgorithmName]::SHA256,
+        [System.Security.Cryptography.RSASignaturePadding]::Pkcs1
+    )
+}
+finally {
+    $rsa.Dispose()
+}
 
-# 生成签名
-$signature = $rsa.SignData(
-    $jsonBytes,
-    [System.Security.Cryptography.HashAlgorithmName]::SHA256,
-    [System.Security.Cryptography.RSASignaturePadding]::Pkcs1
-)
+$signatureBase64 = [Convert]::ToBase64String($signatureBytes)
+[System.IO.File]::WriteAllText($OutputPath, $signatureBase64, [System.Text.Encoding]::ASCII)
 
-# 转换为 Base64
-$signatureBase64 = [Convert]::ToBase64String($signature)
-
-# 写入签名文件
-Set-Content -Path $OutputPath -Value $signatureBase64 -Encoding ASCII
-
-Write-Host "=== 完成 ===" -ForegroundColor Green
-Write-Host "签名文件: $OutputPath"
-Write-Host "签名长度: $($signature.Length) 字节"
+Write-Host "Signed manifest file."
+Write-Host "Manifest:  $FilesJsonPath"
+Write-Host "Signature: $OutputPath"