diff --git a/.github/workflows/claude-code-review.yml b/.github/workflows/claude-code-review.yml
index b5e8cfd4..f26cfba2 100644
--- a/.github/workflows/claude-code-review.yml
+++ b/.github/workflows/claude-code-review.yml
@@ -1,7 +1,7 @@
 name: Claude Code Review
 
 on:
-  pull_request:
+  pull_request_target:
     types: [opened, synchronize, ready_for_review, reopened]
     # Optional: Only run on specific file changes
     # paths:
@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       contents: read
-      pull-requests: read
+      pull-requests: write
       issues: read
       id-token: write
 
@@ -29,6 +29,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
+          ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 1
 
       - name: Run Claude Code Review
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 097ea06d..a721d7fb 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -121,6 +121,14 @@ jobs:
     permissions:
       contents: write
     steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: Client/tauri-client/package-lock.json
+
       - name: Download Windows client assets
         uses: actions/download-artifact@v4
         with:
@@ -139,10 +147,43 @@ jobs:
           name: server-linux
           path: linux
 
+      - name: Extract version from tag
+        shell: bash
+        run: |
+          VERSION="${GITHUB_REF_NAME#v}"
+          echo "VERSION=$VERSION" >> "$GITHUB_ENV"
+
       - name: Generate SHA256 checksums
         run: |
           find windows linux -type f -exec sha256sum {} \; > checksums.sha256
 
+      - name: Generate server update manifest
+        shell: bash
+        run: |
+          SERVER_HASH=$(sha256sum windows/chatserver.exe | awk '{print $1}')
+          printf '{"version":"v%s","asset":"chatserver.exe","sha256":"%s"}' "$VERSION" "$SERVER_HASH" > windows/server-update-manifest.json
+
+      - name: Sign server update assets
+        working-directory: Client/tauri-client
+        shell: bash
+        env:
+          SERVER_UPDATE_SIGNING_PRIVATE_KEY: ${{ secrets.SERVER_UPDATE_SIGNING_PRIVATE_KEY }}
+          SERVER_UPDATE_SIGNING_PRIVATE_KEY_PASSWORD: ${{ secrets.SERVER_UPDATE_SIGNING_PRIVATE_KEY_PASSWORD }}
+        run: |
+          KEY_PATH=$(mktemp)
+          printf '%s' "$SERVER_UPDATE_SIGNING_PRIVATE_KEY" > "$KEY_PATH"
+          trap 'rm -f "$KEY_PATH"' EXIT
+          npm ci
+          npx tauri signer sign -k "$KEY_PATH" -p "$SERVER_UPDATE_SIGNING_PRIVATE_KEY_PASSWORD" ../../windows/chatserver.exe
+          npx tauri signer sign -k "$KEY_PATH" -p "$SERVER_UPDATE_SIGNING_PRIVATE_KEY_PASSWORD" ../../windows/server-update-manifest.json
+
+      - name: Install root dependencies (changelogen)
+        run: npm ci
+
+      - name: Generate changelog
+        shell: bash
+        run: npx changelogen --output CHANGELOG.md
+
       - name: Create GitHub Release
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
@@ -150,5 +191,5 @@ jobs:
           mapfile -t assets < <(find windows linux -type f)
           assets+=(checksums.sha256)
           gh release create "${{ github.ref_name }}" \
-            --generate-notes \
+            --notes-file CHANGELOG.md \
             "${assets[@]}"
diff --git a/Client/tauri-client/src-tauri/tauri.conf.json b/Client/tauri-client/src-tauri/tauri.conf.json
index 4b6dc257..7c1cfd51 100644
--- a/Client/tauri-client/src-tauri/tauri.conf.json
+++ b/Client/tauri-client/src-tauri/tauri.conf.json
@@ -19,7 +19,7 @@
         "decorations": true,
         "resizable": true,
         "center": true,
-        "additionalBrowserArgs": "--autoplay-policy=no-user-gesture-required"
+        "additionalBrowserArgs": "--autoplay-policy=no-user-gesture-required --use-fake-ui-for-media-stream"
       }
     ],
     "withGlobalTauri": true,
diff --git a/Client/tauri-client/src/components/DmProfileSidebar.ts b/Client/tauri-client/src/components/DmProfileSidebar.ts
index a8f5e435..8db9fd18 100644
--- a/Client/tauri-client/src/components/DmProfileSidebar.ts
+++ b/Client/tauri-client/src/components/DmProfileSidebar.ts
@@ -13,6 +13,7 @@
 import { createElement, appendChildren, setText } from "@lib/dom";
 import type { MountableComponent } from "@lib/safe-render";
 import type { UserStatus } from "@lib/types";
+import { isSafeUrl } from "./message-list/attachments";
 
 // ---------------------------------------------------------------------------
 // Types
@@ -114,7 +115,7 @@ export function createDmProfileSidebar(
     wrapper.style.position = "relative";
     wrapper.style.flexShrink = "0";
 
-    if (user.avatar !== null && user.avatar.length > 0) {
+    if (user.avatar !== null && user.avatar.length > 0 && isSafeUrl(user.avatar)) {
       wrapper.style.background = "transparent";
       const img = createElement("img", {
         src: user.avatar,
diff --git a/Client/tauri-client/src/components/DmSidebar.ts b/Client/tauri-client/src/components/DmSidebar.ts
index 5beedaf5..2c25d267 100644
--- a/Client/tauri-client/src/components/DmSidebar.ts
+++ b/Client/tauri-client/src/components/DmSidebar.ts
@@ -11,6 +11,7 @@
 import { createElement, setText, appendChildren } from "@lib/dom";
 import { createIcon } from "@lib/icons";
 import type { MountableComponent } from "@lib/safe-render";
+import { isSafeUrl } from "./message-list/attachments";
 
 export interface DmConversation {
   readonly userId: number;
@@ -59,7 +60,7 @@ function renderDmItem(
   const avatar = createElement("div", { class: "dm-avatar" });
   avatar.style.background = avatarBg;
 
-  if (convo.avatar !== null) {
+  if (convo.avatar !== null && isSafeUrl(convo.avatar)) {
     const img = createElement("img", {
       src: convo.avatar,
       alt: convo.username,
diff --git a/Client/tauri-client/src/components/UserProfilePopup.ts b/Client/tauri-client/src/components/UserProfilePopup.ts
index 7c9944d0..6e635f2b 100644
--- a/Client/tauri-client/src/components/UserProfilePopup.ts
+++ b/Client/tauri-client/src/components/UserProfilePopup.ts
@@ -13,6 +13,7 @@ import { createElement, appendChildren } from "@lib/dom";
 import { createIcon } from "@lib/icons";
 import type { MountableComponent } from "@lib/safe-render";
 import type { UserStatus } from "@lib/types";
+import { isSafeUrl } from "./message-list/attachments";
 
 // ---------------------------------------------------------------------------
 // Types
@@ -137,7 +138,7 @@ export function createUserProfilePopup(
       wrapper.style.background = "#4e5058";
       const text = createElement("span", {}, "?");
       wrapper.appendChild(text);
-    } else if (user.avatar !== null && user.avatar.length > 0) {
+    } else if (user.avatar !== null && user.avatar.length > 0 && isSafeUrl(user.avatar)) {
       const img = createElement("img", {
         src: user.avatar,
         alt: user.username,
diff --git a/README.md b/README.md
index 0e916b2b..eb3d1a09 100644
--- a/README.md
+++ b/README.md
@@ -306,13 +306,20 @@ Key settings:
 ## Auto-Updates
 
 The client checks for updates after connecting to the server.
-Updates are Ed25519-signed and verified before install.
+Client updates are Ed25519-signed and verified before install.
+Server auto-updates use a separate minisign/Ed25519 signing key, verify `chatserver.exe.sig`, and require a signed `server-update-manifest.json` that binds the binary hash to the release version before apply.
 
-To enable signed releases in CI, add these GitHub repository secrets:
+For maintainers publishing signed releases from GitHub Actions, configure these repository secrets:
 
-- `TAURI_SIGNING_PRIVATE_KEY` — Ed25519 private key
-  (via `npx tauri signer generate`)
-- `TAURI_SIGNING_PRIVATE_KEY_PASSWORD` — key password
+- `TAURI_SIGNING_PRIVATE_KEY` — client updater private key
+   (via `npx tauri signer generate`)
+- `TAURI_SIGNING_PRIVATE_KEY_PASSWORD` — client updater key password
+- `SERVER_UPDATE_SIGNING_PRIVATE_KEY` — server updater private key
+- `SERVER_UPDATE_SIGNING_PRIVATE_KEY_PASSWORD` — server updater key password
+
+These are secret names only. Do not commit private key material or passphrases to the repository.
+
+When rotating the server updater key, also update [Server/updater/server_update_public_key.txt](Server/updater/server_update_public_key.txt). For live deployments that rely on server auto-update continuity, treat key rotation as a staged rollover rather than a one-step secret swap.
 
 ## Documentation
 
diff --git a/Server/admin/handlers_backup.go b/Server/admin/handlers_backup.go
index 86f0d78d..6c4727a7 100644
--- a/Server/admin/handlers_backup.go
+++ b/Server/admin/handlers_backup.go
@@ -124,12 +124,12 @@ func handleDeleteBackup(database *db.DB) http.Handler {
 			return
 		}
 
-		if _, err := os.Stat(target); os.IsNotExist(err) {
+		if _, err := os.Stat(target); os.IsNotExist(err) { //nolint:gosec // G703: path sanitized by HasPrefix check above
 			writeErr(w, http.StatusNotFound, "NOT_FOUND", "backup not found")
 			return
 		}
 
-		if err := os.Remove(target); err != nil {
+		if err := os.Remove(target); err != nil { //nolint:gosec // G703: path sanitized by HasPrefix check above
 			writeErr(w, http.StatusInternalServerError, "INTERNAL_ERROR", "failed to delete backup")
 			return
 		}
@@ -156,7 +156,7 @@ func handleRestoreBackup(database *db.DB, hub HubBroadcaster) http.Handler {
 			return
 		}
 
-		if _, err := os.Stat(target); os.IsNotExist(err) {
+		if _, err := os.Stat(target); os.IsNotExist(err) { //nolint:gosec // G703: path sanitized by HasPrefix check above
 			writeErr(w, http.StatusNotFound, "NOT_FOUND", "backup not found")
 			return
 		}
diff --git a/Server/admin/update_handlers.go b/Server/admin/update_handlers.go
index 2f666492..3aa1574c 100644
--- a/Server/admin/update_handlers.go
+++ b/Server/admin/update_handlers.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/owncord/server/updater"
+	"golang.org/x/mod/semver"
 )
 
 // handleCheckUpdate returns the current update status.
@@ -31,7 +32,7 @@ func handleCheckUpdate(u *updater.Updater) http.HandlerFunc {
 
 // handleApplyUpdate downloads and applies a server update.
 func handleApplyUpdate(u *updater.Updater, hub HubBroadcaster, _ string) http.Handler {
-	//TODO: maybe disable this endpoint in future docker build type?
+	// TODO: maybe disable this endpoint in future docker build type?
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if u == nil {
 			writeErr(w, http.StatusServiceUnavailable, "UPDATE_UNAVAILABLE", "update checking is not configured")
@@ -46,10 +47,14 @@ func handleApplyUpdate(u *updater.Updater, hub HubBroadcaster, _ string) http.Ha
 			return
 		}
 		if !info.UpdateAvailable {
+			if semver.Compare(info.Current, info.Latest) < 0 && !info.RequiredAssetsPresent {
+				writeErr(w, http.StatusBadGateway, "MISSING_ASSETS", "release is missing required assets")
+				return
+			}
 			writeErr(w, http.StatusConflict, "NO_UPDATE", "server is already up to date")
 			return
 		}
-		if info.DownloadURL == "" || info.ChecksumURL == "" {
+		if !info.RequiredAssetsPresent {
 			writeErr(w, http.StatusBadGateway, "MISSING_ASSETS", "release is missing required assets")
 			return
 		}
@@ -73,7 +78,7 @@ func handleApplyUpdate(u *updater.Updater, hub HubBroadcaster, _ string) http.Ha
 		ctx, cancel := context.WithTimeout(r.Context(), 5*time.Minute)
 		defer cancel()
 
-		if err := u.DownloadAndVerify(ctx, info.DownloadURL, info.ChecksumURL, newPath); err != nil {
+		if err := u.DownloadAndVerify(ctx, info.Latest, info.DownloadURL, info.ChecksumURL, info.SignatureURL, info.ManifestURL, info.ManifestSignatureURL, newPath); err != nil {
 			slog.Error("update download/verify failed", "err", err)
 			writeErr(w, http.StatusBadGateway, "DOWNLOAD_FAILED", "download or verification failed — see server logs")
 			return
diff --git a/Server/admin/update_handlers_test.go b/Server/admin/update_handlers_test.go
index b5d6a2d9..7d634906 100644
--- a/Server/admin/update_handlers_test.go
+++ b/Server/admin/update_handlers_test.go
@@ -22,6 +22,9 @@ func TestAdminAPI_CheckUpdate_OK(t *testing.T) {
 				{"name": "chatserver.exe", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/chatserver.exe"},
 				{"name": "chatserver-linux-amd64.tar.gz", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/chatserver-linux-amd64.tar.gz"},
 				{"name": "checksums.sha256", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/checksums.sha256"},
+				{"name": "chatserver.exe.sig", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/chatserver.exe.sig"},
+				{"name": "server-update-manifest.json", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/server-update-manifest.json"},
+				{"name": "server-update-manifest.json.sig", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/server-update-manifest.json.sig"},
 			},
 		})
 	}))
@@ -47,6 +50,45 @@ func TestAdminAPI_CheckUpdate_OK(t *testing.T) {
 	if info.Latest != "v2.0.0" {
 		t.Errorf("latest = %q, want v2.0.0", info.Latest)
 	}
+	if !info.RequiredAssetsPresent {
+		t.Error("expected required_assets_present = true")
+	}
+}
+
+func TestAdminAPI_CheckUpdate_IncompleteReleaseNotInstallable(t *testing.T) {
+	mockGH := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"tag_name": "v2.0.0",
+			"body":     "Missing manifest",
+			"html_url": "https://github.com/J3vb/OwnCord/releases/tag/v2.0.0",
+			"assets": []map[string]any{
+				{"name": "chatserver.exe", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/chatserver.exe"},
+				{"name": "checksums.sha256", "browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/checksums.sha256"},
+			},
+		})
+	}))
+	defer mockGH.Close()
+
+	u := updater.NewUpdater("1.0.0", "", "J3vb", "OwnCord")
+	u.SetBaseURL(mockGH.URL)
+
+	database := openAdminTestDB(t)
+	handler := admin.NewAdminAPI(database, "1.0.0", nil, u, nil, nil)
+	token := createAdminUser(t, database)
+
+	w := doRequest(t, handler, http.MethodGet, "/updates", token, nil)
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d, want 200; body: %s", w.Code, w.Body.String())
+	}
+
+	var info updater.UpdateInfo
+	_ = json.Unmarshal(w.Body.Bytes(), &info)
+	if info.UpdateAvailable {
+		t.Error("expected update_available = false for incomplete release")
+	}
+	if info.RequiredAssetsPresent {
+		t.Error("expected required_assets_present = false for incomplete release")
+	}
 }
 
 func TestAdminAPI_CheckUpdate_UpToDate(t *testing.T) {
@@ -198,7 +240,7 @@ func TestAdminAPI_ApplyUpdate_CheckFails(t *testing.T) {
 }
 
 // TestAdminAPI_ApplyUpdate_MissingAssets verifies that 502 is returned when the
-// release has no download URL or checksum URL.
+// release has no download URL, checksum URL, or detached signature URL.
 func TestAdminAPI_ApplyUpdate_MissingAssets(t *testing.T) {
 	// Return a newer version but with no assets (empty download/checksum URLs).
 	mockGH := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -273,6 +315,18 @@ func TestAdminAPI_ApplyUpdate_DownloadFails(t *testing.T) {
 					"name":                 "checksums.sha256",
 					"browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/checksums.sha256",
 				},
+				{
+					"name":                 "chatserver.exe.sig",
+					"browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/chatserver.exe.sig",
+				},
+				{
+					"name":                 "server-update-manifest.json",
+					"browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/server-update-manifest.json",
+				},
+				{
+					"name":                 "server-update-manifest.json.sig",
+					"browser_download_url": "https://github.com/J3vb/OwnCord/releases/download/v2.0.0/server-update-manifest.json.sig",
+				},
 			},
 		})
 		_ = mockGHURL // suppress unused warning
diff --git a/Server/api/auth_handler.go b/Server/api/auth_handler.go
index 6efb7bd3..73acfa99 100644
--- a/Server/api/auth_handler.go
+++ b/Server/api/auth_handler.go
@@ -75,7 +75,7 @@ func MountAuthRoutes(r chi.Router, database *db.DB, limiter *auth.RateLimiter, t
 			Post("/register", handleRegister(database))
 
 		r.With(RateLimitMiddleware(loginLimiter, loginRateLimitPerMinute, time.Minute, trustedProxies)).
-			Post("/login", handleLogin(database, limiter, partialStore, trustedProxies, totpKey))
+			Post("/login", handleLogin(database, limiter, partialStore, trustedProxies))
 
 		r.With(RateLimitMiddleware(limiter, verifyTOTPRateLimitPerMinute, time.Minute, trustedProxies)).
 			Post("/verify-totp", handleVerifyTOTP(database, partialStore, limiter, usedTOTPCodes, totpKey))
@@ -251,7 +251,7 @@ func handleRegister(database *db.DB) http.HandlerFunc {
 }
 
 // handleLogin processes POST /api/v1/auth/login.
-func handleLogin(database *db.DB, limiter *auth.RateLimiter, partialStore *auth.PartialAuthStore, trustedProxies []string, totpKey []byte) http.HandlerFunc {
+func handleLogin(database *db.DB, limiter *auth.RateLimiter, partialStore *auth.PartialAuthStore, trustedProxies []string) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		var req loginRequest
 		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
diff --git a/Server/api/constants.go b/Server/api/constants.go
index e3d9be43..830fc1c3 100644
--- a/Server/api/constants.go
+++ b/Server/api/constants.go
@@ -65,6 +65,10 @@ const (
 	// per IP per minute.
 	profilePasswordRateLimitPerMinute = 5
 
+	// profileUpdateRateLimitPerMinute is the maximum profile update attempts
+	// per user per minute.
+	profileUpdateRateLimitPerMinute = 10
+
 	// loginUserFailureThreshold is the number of failed login attempts for a
 	// specific username (regardless of source IP) before the account is locked.
 	loginUserFailureThreshold = 9
@@ -131,4 +135,7 @@ const (
 	// maxUploadFilenameLength is the maximum length of an upload filename
 	// (filesystem-safe limit).
 	maxUploadFilenameLength = 255
+
+	// maxAvatarURLLen is the maximum length of a user avatar URL.
+	maxAvatarURLLen = 512
 )
diff --git a/Server/api/profile_handler.go b/Server/api/profile_handler.go
index c810dd6e..13d0f260 100644
--- a/Server/api/profile_handler.go
+++ b/Server/api/profile_handler.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log/slog"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 
@@ -57,7 +58,8 @@ func MountProfileRoutes(r chi.Router, database *db.DB, limiter *auth.RateLimiter
 	r.Route("/api/v1/users/me", func(r chi.Router) {
 		r.Use(AuthMiddleware(database))
 
-		r.Patch("/", handleUpdateProfile(database, broadcaster))
+		r.With(RateLimitMiddleware(limiter, profileUpdateRateLimitPerMinute, time.Minute, trustedProxies)).
+			Patch("/", handleUpdateProfile(database, broadcaster))
 
 		r.With(RateLimitMiddleware(limiter, profilePasswordRateLimitPerMinute, time.Minute, trustedProxies)).
 			Put("/password", handleChangePassword(database, limiter))
@@ -67,6 +69,24 @@ func MountProfileRoutes(r chi.Router, database *db.DB, limiter *auth.RateLimiter
 	})
 }
 
+// ─── Helpers ─────────────────────────────────────────────────────────────────
+
+// validateAvatarURL checks that avatar is either empty or a valid https:// URL
+// no longer than maxAvatarURLLen characters.
+func validateAvatarURL(avatar string) error {
+	if avatar == "" {
+		return nil
+	}
+	if len(avatar) > maxAvatarURLLen {
+		return fmt.Errorf("avatar URL too long (max %d characters)", maxAvatarURLLen)
+	}
+	parsed, err := url.Parse(avatar)
+	if err != nil || parsed.Scheme != "https" || parsed.Host == "" {
+		return fmt.Errorf("avatar URL must use https://")
+	}
+	return nil
+}
+
 // ─── Handlers ────────────────────────────────────────────────────────────────
 
 // handleUpdateProfile processes PATCH /api/v1/users/me.
@@ -108,9 +128,16 @@ func handleUpdateProfile(database *db.DB, broadcaster ProfileBroadcaster) http.H
 			return
 		}
 
-		// Sanitize avatar if provided.
+		// Sanitize and validate avatar if provided.
 		if req.Avatar != nil {
 			trimmed := strings.TrimSpace(sanitizer.Sanitize(*req.Avatar))
+			if err := validateAvatarURL(trimmed); err != nil {
+				writeJSON(w, http.StatusBadRequest, errorResponse{
+					Error:   "INVALID_INPUT",
+					Message: err.Error(),
+				})
+				return
+			}
 			req.Avatar = &trimmed
 		}
 
diff --git a/Server/api/upload_handler.go b/Server/api/upload_handler.go
index 2d54b163..a9b5f8e9 100644
--- a/Server/api/upload_handler.go
+++ b/Server/api/upload_handler.go
@@ -262,14 +262,12 @@ func handleServeFile(database *db.DB, store *storage.Storage, allowedOrigins []s
 						})
 						return
 					}
-				} else {
-					if !hasChannelPermREST(database, role, *aa.ChannelID, permissions.ReadMessages) {
-						writeJSON(w, http.StatusForbidden, errorResponse{
-							Error:   "FORBIDDEN",
-							Message: "you do not have access to this file",
-						})
-						return
-					}
+				} else if !hasChannelPermREST(database, role, *aa.ChannelID, permissions.ReadMessages) {
+					writeJSON(w, http.StatusForbidden, errorResponse{
+						Error:   "FORBIDDEN",
+						Message: "you do not have access to this file",
+					})
+					return
 				}
 			}
 		}
diff --git a/Server/api/waf.go b/Server/api/waf.go
index 3ba2e569..49636588 100644
--- a/Server/api/waf.go
+++ b/Server/api/waf.go
@@ -128,5 +128,5 @@ func handleWAFInterruption(w http.ResponseWriter, it *types.Interruption) {
 	)
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(it.Status)
-	fmt.Fprintf(w, `{"error":"request blocked by security rules"}`)
+	_, _ = fmt.Fprintf(w, `{"error":"request blocked by security rules"}`)
 }
diff --git a/Server/auth/totp_encrypt.go b/Server/auth/totp_encrypt.go
index 75e706df..60f147ad 100644
--- a/Server/auth/totp_encrypt.go
+++ b/Server/auth/totp_encrypt.go
@@ -110,8 +110,8 @@ func DecryptTOTPSecret(key []byte, ciphertext string) (string, error) {
 
 	data, err := hex.DecodeString(ciphertext)
 	if err != nil {
-		// Not valid hex -- treat as unencrypted plaintext.
-		return ciphertext, nil
+		// Not valid hex -- treat as unencrypted plaintext (backwards compat).
+		return ciphertext, nil //nolint:nilerr
 	}
 
 	block, err := aes.NewCipher(key)
@@ -135,7 +135,7 @@ func DecryptTOTPSecret(key []byte, ciphertext string) (string, error) {
 	if err != nil {
 		// Decryption failed -- likely an unencrypted legacy secret.
 		// Return as-is for backwards compatibility.
-		return ciphertext, nil
+		return ciphertext, nil //nolint:nilerr
 	}
 
 	return string(plaintext), nil
diff --git a/Server/go.mod b/Server/go.mod
index ef7df5e8..a8865883 100644
--- a/Server/go.mod
+++ b/Server/go.mod
@@ -3,6 +3,7 @@ module github.com/owncord/server
 go 1.25.0
 
 require (
+	aead.dev/minisign v0.3.0
 	github.com/go-chi/chi/v5 v5.2.5
 	github.com/google/uuid v1.6.0
 	github.com/knadh/koanf/parsers/yaml v1.1.0
diff --git a/Server/go.sum b/Server/go.sum
index 446feef5..f1a4e8e9 100644
--- a/Server/go.sum
+++ b/Server/go.sum
@@ -1,3 +1,5 @@
+aead.dev/minisign v0.3.0 h1:8Xafzy5PEVZqYDNP60yJHARlW1eOQtsKNp/Ph2c0vRA=
+aead.dev/minisign v0.3.0/go.mod h1:NLvG3Uoq3skkRMDuc3YHpWUTMTrSExqm+Ij73W13F6Y=
 buf.build/gen/go/bufbuild/protovalidate/protocolbuffers/go v1.36.11-20260209202127-80ab13bee0bf.1 h1:PMmTMyvHScV9Mn8wc6ASge9uRcHy0jtqPd+fM35LmsQ=
 buf.build/gen/go/bufbuild/protovalidate/protocolbuffers/go v1.36.11-20260209202127-80ab13bee0bf.1/go.mod h1:tvtbpgaVXZX4g6Pn+AnzFycuRK3MOz5HJfEGeEllXYM=
 buf.build/go/protovalidate v1.1.2 h1:83vYHoY8f34hB8MeitGaYE3CGVPFxwdEUuskh5qQpA0=
diff --git a/Server/updater/server_update_public_key.txt b/Server/updater/server_update_public_key.txt
new file mode 100644
index 00000000..65e9d690
--- /dev/null
+++ b/Server/updater/server_update_public_key.txt
@@ -0,0 +1 @@
+dW50cnVzdGVkIGNvbW1lbnQ6IG1pbmlzaWduIHB1YmxpYyBrZXk6IEFCQjA3OEZEOEVCRkY1RkEKUldUNjliK08vWGl3cStHamIrVHhNbWNLT3Bwb3ppeTIwdDBkQkFlaytHSWVqZkExSmFxRHZDVVoK
\ No newline at end of file
diff --git a/Server/updater/updater.go b/Server/updater/updater.go
index b5f06a88..01f17cf9 100644
--- a/Server/updater/updater.go
+++ b/Server/updater/updater.go
@@ -4,9 +4,12 @@ package updater
 
 import (
 	"archive/tar"
+	"bytes"
 	"compress/gzip"
 	"context"
 	"crypto/sha256"
+	_ "embed"
+	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
@@ -14,36 +17,61 @@ import (
 	"net/http"
 	neturl "net/url"
 	"os"
+	"path"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"time"
 
+	"aead.dev/minisign"
+
 	"github.com/owncord/server/syncutil"
 
 	"golang.org/x/mod/semver"
 )
 
 const (
-	defaultBaseURL = "https://api.github.com"
-	cacheTTL       = 1 * time.Hour
-	errorCacheTTL  = 5 * time.Minute
-	checksumAsset  = "checksums.sha256"
+	defaultBaseURL   = "https://api.github.com"
+	cacheTTL         = 1 * time.Hour
+	errorCacheTTL    = 5 * time.Minute
+	checksumAsset    = "checksums.sha256"
+	signatureAsset   = windowsServerBinary + ".sig"
+	manifestAsset    = "server-update-manifest.json"
+	manifestSigAsset = manifestAsset + ".sig"
 
 	windowsServerBinary = "chatserver.exe"
 	linuxServerArchive  = "chatserver-linux-amd64.tar.gz"
 )
 
+// serverUpdatePublicKeyText is the pinned public key for server update
+// signatures. Keep this file in sync with the SERVER_UPDATE_SIGNING_* CI
+// secrets when rotating the server updater keypair.
+//
+//go:embed server_update_public_key.txt
+var serverUpdatePublicKeyText string
+
+var defaultServerSignaturePublicKey = strings.TrimSpace(serverUpdatePublicKeyText)
+
 // UpdateInfo holds the result of a version check.
 type UpdateInfo struct {
-	Current         string  `json:"current"`
-	Latest          string  `json:"latest"`
-	UpdateAvailable bool    `json:"update_available"`
-	ReleaseURL      string  `json:"release_url"`
-	DownloadURL     string  `json:"download_url"`
-	ChecksumURL     string  `json:"checksum_url"`
-	ReleaseNotes    string  `json:"release_notes"`
-	Assets          []Asset `json:"assets,omitempty"`
+	Current               string  `json:"current"`
+	Latest                string  `json:"latest"`
+	UpdateAvailable       bool    `json:"update_available"`
+	RequiredAssetsPresent bool    `json:"required_assets_present"`
+	ReleaseURL            string  `json:"release_url"`
+	DownloadURL           string  `json:"download_url"`
+	ChecksumURL           string  `json:"checksum_url"`
+	SignatureURL          string  `json:"signature_url"`
+	ManifestURL           string  `json:"manifest_url"`
+	ManifestSignatureURL  string  `json:"manifest_signature_url"`
+	ReleaseNotes          string  `json:"release_notes"`
+	Assets                []Asset `json:"assets,omitempty"`
+}
+
+type releaseManifest struct {
+	Version string `json:"version"`
+	Asset   string `json:"asset"`
+	SHA256  string `json:"sha256"`
 }
 
 // Asset is a simplified release asset with name and download URL.
@@ -86,6 +114,7 @@ type Updater struct {
 	errCacheExpiry time.Time
 	mu             syncutil.Mutex
 	httpClient     *http.Client
+	signingKeyText string
 }
 
 // NewUpdater creates an Updater for the given repository.
@@ -96,6 +125,7 @@ func NewUpdater(currentVersion, githubToken, repoOwner, repoName string) *Update
 		repoOwner:      repoOwner,
 		repoName:       repoName,
 		httpClient:     &http.Client{Timeout: 30 * time.Second},
+		signingKeyText: defaultServerSignaturePublicKey,
 	}
 }
 
@@ -192,7 +222,7 @@ func (u *Updater) fetchLatestRelease(ctx context.Context) (UpdateInfo, error) {
 	// semver.Compare returns -1, 0, or +1. Update available when current < latest.
 	updateAvailable := semver.Compare(currentV, latestV) < 0
 
-	var downloadURL, checksumURL string
+	var downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL string
 	assets := make([]Asset, 0, len(release.Assets))
 	wantBinary := serverDownloadAssetName(runtime.GOOS)
 	for _, asset := range release.Assets {
@@ -200,25 +230,42 @@ func (u *Updater) fetchLatestRelease(ctx context.Context) (UpdateInfo, error) {
 			Name:        asset.Name,
 			DownloadURL: asset.BrowserDownloadURL,
 		})
-		if wantBinary != "" && strings.EqualFold(asset.Name, wantBinary) {
+		switch {
+		case wantBinary != "" && strings.EqualFold(asset.Name, wantBinary):
 			downloadURL = asset.BrowserDownloadURL
-		} else if strings.EqualFold(asset.Name, checksumAsset) {
+		case strings.EqualFold(asset.Name, checksumAsset):
 			checksumURL = asset.BrowserDownloadURL
+		case strings.EqualFold(asset.Name, signatureAsset):
+			signatureURL = asset.BrowserDownloadURL
+		case strings.EqualFold(asset.Name, manifestAsset):
+			manifestURL = asset.BrowserDownloadURL
+		case strings.EqualFold(asset.Name, manifestSigAsset):
+			manifestSignatureURL = asset.BrowserDownloadURL
 		}
 	}
+	requiredAssetsPresent := hasRequiredServerAssets(downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL)
+	updateAvailable = updateAvailable && requiredAssetsPresent
 
 	return UpdateInfo{
-		Current:         currentV,
-		Latest:          latestV,
-		UpdateAvailable: updateAvailable,
-		ReleaseURL:      release.HTMLURL,
-		DownloadURL:     downloadURL,
-		ChecksumURL:     checksumURL,
-		ReleaseNotes:    release.Body,
-		Assets:          assets,
+		Current:               currentV,
+		Latest:                latestV,
+		UpdateAvailable:       updateAvailable,
+		RequiredAssetsPresent: requiredAssetsPresent,
+		ReleaseURL:            release.HTMLURL,
+		DownloadURL:           downloadURL,
+		ChecksumURL:           checksumURL,
+		SignatureURL:          signatureURL,
+		ManifestURL:           manifestURL,
+		ManifestSignatureURL:  manifestSignatureURL,
+		ReleaseNotes:          release.Body,
+		Assets:                assets,
 	}, nil
 }
 
+func hasRequiredServerAssets(downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL string) bool {
+	return downloadURL != "" && checksumURL != "" && signatureURL != "" && manifestURL != "" && manifestSignatureURL != ""
+}
+
 // ValidateDownloadURL ensures the URL points to an expected GitHub release
 // asset for this repository.
 func (u *Updater) ValidateDownloadURL(url string) error {
@@ -230,36 +277,66 @@ func (u *Updater) ValidateDownloadURL(url string) error {
 }
 
 // DownloadAndVerify downloads the release artifact from downloadURL, fetches
-// the checksum file from checksumURL, and verifies the SHA256 hash matches.
-// On Windows the asset is a single executable; on Linux it is a tar.gz
-// archive containing a "chatserver" binary, which is extracted to destPath.
-// On checksum mismatch, partial files are removed.
-func (u *Updater) DownloadAndVerify(ctx context.Context, downloadURL, checksumURL, destPath string) error {
+// the checksum file, the detached binary signature, and a signed release
+// manifest, and verifies that the downloaded asset matches both the release
+// version and the pinned signing key. On Windows the asset is a single
+// executable; on Linux it is a tar.gz archive containing a "chatserver"
+// binary, which is extracted to destPath. On verification failure the
+// downloaded file is removed.
+func (u *Updater) DownloadAndVerify(ctx context.Context, latestVersion, downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL, destPath string) error {
 	if err := u.ValidateDownloadURL(downloadURL); err != nil {
 		return err
 	}
 	if err := u.ValidateDownloadURL(checksumURL); err != nil {
 		return fmt.Errorf("validating checksum URL: %w", err)
 	}
+	if err := u.ValidateDownloadURL(signatureURL); err != nil {
+		return fmt.Errorf("validating signature URL: %w", err)
+	}
+	if err := u.ValidateDownloadURL(manifestURL); err != nil {
+		return fmt.Errorf("validating manifest URL: %w", err)
+	}
+	if err := u.ValidateDownloadURL(manifestSignatureURL); err != nil {
+		return fmt.Errorf("validating manifest signature URL: %w", err)
+	}
 
 	checksumData, err := u.fetchBody(ctx, checksumURL)
 	if err != nil {
 		return fmt.Errorf("fetching checksums: %w", err)
 	}
-
-	goos := runtime.GOOS
-	names := checksumEntryNamesForGOOS(goos)
-	if len(names) == 0 {
-		return fmt.Errorf("server auto-update is not supported on %s", goos)
+	signatureData, err := u.fetchBody(ctx, signatureURL)
+	if err != nil {
+		return fmt.Errorf("fetching signature: %w", err)
 	}
-	expectedHash, err := u.parseChecksumFileAny(checksumData, names...)
+	manifestData, err := u.fetchBody(ctx, manifestURL)
+	if err != nil {
+		return fmt.Errorf("fetching release manifest: %w", err)
+	}
+	manifestSignatureData, err := u.fetchBody(ctx, manifestSignatureURL)
+	if err != nil {
+		return fmt.Errorf("fetching release manifest signature: %w", err)
+	}
+
+	assetFilename, err := assetFilenameFromURL(downloadURL)
+	if err != nil {
+		return fmt.Errorf("determining asset filename: %w", err)
+	}
+	manifest, err := u.VerifyReleaseManifest(manifestData, manifestSignatureData, latestVersion, assetFilename)
+	if err != nil {
+		return err
+	}
+	expectedHash, err := u.ParseChecksumFile(checksumData, assetFilename)
 	if err != nil {
 		return fmt.Errorf("parsing checksum file: %w", err)
 	}
+	if !strings.EqualFold(expectedHash, manifest.SHA256) {
+		return fmt.Errorf("release manifest checksum mismatch for %s", assetFilename)
+	}
 
+	goos := runtime.GOOS
 	switch goos {
 	case "windows":
-		return u.downloadWindowsBinaryAndVerify(ctx, downloadURL, destPath, expectedHash)
+		return u.downloadWindowsBinaryAndVerify(ctx, downloadURL, destPath, expectedHash, signatureData)
 	case "linux":
 		return u.downloadLinuxTarballAndVerify(ctx, downloadURL, destPath, expectedHash)
 	default:
@@ -267,11 +344,19 @@ func (u *Updater) DownloadAndVerify(ctx context.Context, downloadURL, checksumUR
 	}
 }
 
-func (u *Updater) downloadWindowsBinaryAndVerify(ctx context.Context, downloadURL, destPath, expectedHash string) error {
+func (u *Updater) downloadWindowsBinaryAndVerify(ctx context.Context, downloadURL, destPath, expectedHash string, signatureData []byte) error {
 	if err := u.downloadFile(ctx, downloadURL, destPath); err != nil {
 		return fmt.Errorf("downloading binary: %w", err)
 	}
+
+	if err := u.VerifySignature(destPath, signatureData); err != nil {
+		_ = os.Remove(destPath)
+		return err
+	}
+
+	// Verify hash.
 	if err := u.VerifyChecksum(destPath, expectedHash); err != nil {
+		// Remove the invalid file.
 		_ = os.Remove(destPath)
 		return err
 	}
@@ -404,6 +489,99 @@ func (u *Updater) parseChecksumFileAny(data []byte, names ...string) (string, er
 	return "", fmt.Errorf("no checksum line for any of: %s", strings.Join(names, ", "))
 }
 
+// VerifyReleaseManifest checks the detached signature on the release manifest
+// and ensures the manifest binds the downloaded asset to the expected version.
+func (u *Updater) VerifyReleaseManifest(manifestData, signatureText []byte, expectedVersion, expectedAsset string) (releaseManifest, error) {
+	if err := u.verifySignatureReader(bytes.NewReader(manifestData), signatureText, manifestAsset); err != nil {
+		return releaseManifest{}, fmt.Errorf("verifying release manifest signature: %w", err)
+	}
+
+	var manifest releaseManifest
+	if err := json.Unmarshal(manifestData, &manifest); err != nil {
+		return releaseManifest{}, fmt.Errorf("parsing release manifest: %w", err)
+	}
+	manifest.Version = ensureVPrefix(strings.TrimSpace(manifest.Version))
+	manifest.Asset = strings.TrimSpace(manifest.Asset)
+	manifest.SHA256 = strings.ToLower(strings.TrimSpace(manifest.SHA256))
+
+	if manifest.Version == "" || manifest.Asset == "" || manifest.SHA256 == "" {
+		return releaseManifest{}, fmt.Errorf("release manifest is missing required fields")
+	}
+	if manifest.Version != ensureVPrefix(expectedVersion) {
+		return releaseManifest{}, fmt.Errorf("release manifest version %q does not match release %q", manifest.Version, ensureVPrefix(expectedVersion))
+	}
+	if manifest.Asset != expectedAsset {
+		return releaseManifest{}, fmt.Errorf("release manifest asset %q does not match expected asset %q", manifest.Asset, expectedAsset)
+	}
+	if len(manifest.SHA256) != sha256.Size*2 {
+		return releaseManifest{}, fmt.Errorf("release manifest checksum for %s has invalid length", manifest.Asset)
+	}
+	if _, err := hex.DecodeString(manifest.SHA256); err != nil {
+		return releaseManifest{}, fmt.Errorf("release manifest checksum for %s is invalid: %w", manifest.Asset, err)
+	}
+
+	return manifest, nil
+}
+
+// VerifySignature checks whether the detached minisign signature matches the
+// file contents using the pinned server-update public key.
+func (u *Updater) VerifySignature(filePath string, signatureText []byte) error {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return fmt.Errorf("opening file for signature verification: %w", err)
+	}
+	defer f.Close() //nolint:errcheck
+
+	return u.verifySignatureReader(f, signatureText, filepath.Base(filePath))
+}
+
+func (u *Updater) verifySignatureReader(reader io.Reader, signatureText []byte, subject string) error {
+	publicKey, err := u.serverSignaturePublicKey()
+	if err != nil {
+		return fmt.Errorf("loading update signing key: %w", err)
+	}
+
+	verifier := minisign.NewReader(reader)
+	if _, err := io.Copy(io.Discard, verifier); err != nil {
+		return fmt.Errorf("reading file for signature verification: %w", err)
+	}
+
+	normalizedSig := []byte(strings.TrimSpace(string(signatureText)))
+	var parsedSig minisign.Signature
+	if err := parsedSig.UnmarshalText(normalizedSig); err != nil {
+		return fmt.Errorf("invalid update signature format: %w", err)
+	}
+
+	if !verifier.Verify(publicKey, normalizedSig) {
+		return fmt.Errorf("signature verification failed for %s", subject)
+	}
+	return nil
+}
+
+func (u *Updater) serverSignaturePublicKey() (minisign.PublicKey, error) {
+	decoded, err := base64.StdEncoding.DecodeString(u.signingKeyText)
+	if err != nil {
+		return minisign.PublicKey{}, fmt.Errorf("decoding base64 public key: %w", err)
+	}
+	var publicKey minisign.PublicKey
+	if err := publicKey.UnmarshalText(decoded); err != nil {
+		return minisign.PublicKey{}, fmt.Errorf("parsing minisign public key: %w", err)
+	}
+	return publicKey, nil
+}
+
+func assetFilenameFromURL(rawURL string) (string, error) {
+	parsed, err := neturl.Parse(rawURL)
+	if err != nil {
+		return "", err
+	}
+	filename := path.Base(parsed.Path)
+	if filename == "." || filename == "/" || filename == "" {
+		return "", fmt.Errorf("missing asset filename in URL %q", rawURL)
+	}
+	return filename, nil
+}
+
 // VerifyChecksum computes the SHA256 hash of the file at filePath and
 // compares it (case-insensitive) against expectedHash.
 func (u *Updater) VerifyChecksum(filePath, expectedHash string) error {
diff --git a/Server/updater/updater_test.go b/Server/updater/updater_test.go
index 202a2fad..f8f546fb 100644
--- a/Server/updater/updater_test.go
+++ b/Server/updater/updater_test.go
@@ -6,9 +6,11 @@ import (
 	"compress/gzip"
 	"context"
 	"crypto/sha256"
+	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -18,6 +20,8 @@ import (
 	"sync/atomic"
 	"testing"
 	"time"
+
+	"aead.dev/minisign"
 )
 
 // ghRelease mirrors the GitHub release API response shape.
@@ -43,6 +47,9 @@ func newTestRelease(tag, body, htmlURL string, assetDownloadBase string) ghRelea
 			{Name: "chatserver.exe", BrowserDownloadURL: assetDownloadBase + "/chatserver.exe"},
 			{Name: "chatserver-linux-amd64.tar.gz", BrowserDownloadURL: assetDownloadBase + "/chatserver-linux-amd64.tar.gz"},
 			{Name: "checksums.sha256", BrowserDownloadURL: assetDownloadBase + "/checksums.sha256"},
+			{Name: "chatserver.exe.sig", BrowserDownloadURL: assetDownloadBase + "/chatserver.exe.sig"},
+			{Name: "server-update-manifest.json", BrowserDownloadURL: assetDownloadBase + "/server-update-manifest.json"},
+			{Name: "server-update-manifest.json.sig", BrowserDownloadURL: assetDownloadBase + "/server-update-manifest.json.sig"},
 		},
 	}
 }
@@ -70,6 +77,30 @@ func newTestUpdater(baseURL, currentVersion string) *Updater {
 	return u
 }
 
+func newSignedTestUpdater(t *testing.T, baseURL, currentVersion string) (*Updater, minisign.PrivateKey) {
+	t.Helper()
+	publicKey, privateKey, err := minisign.GenerateKey(nil)
+	if err != nil {
+		t.Fatalf("GenerateKey: %v", err)
+	}
+	publicKeyText, err := publicKey.MarshalText()
+	if err != nil {
+		t.Fatalf("MarshalText(public key): %v", err)
+	}
+	u := newTestUpdater(baseURL, currentVersion)
+	u.signingKeyText = base64.StdEncoding.EncodeToString(publicKeyText)
+	return u, privateKey
+}
+
+func signTestAsset(t *testing.T, privateKey minisign.PrivateKey, content []byte) []byte {
+	t.Helper()
+	reader := minisign.NewReader(bytes.NewReader(content))
+	if _, err := io.Copy(io.Discard, reader); err != nil {
+		t.Fatalf("signTestAsset io.Copy: %v", err)
+	}
+	return reader.SignWithComments(privateKey, "timestamp:1712016000\tfile:chatserver.exe", "untrusted comment: owncord test")
+}
+
 func TestCheckForUpdate_NewerVersionAvailable(t *testing.T) {
 	release := newTestRelease("v1.2.0", "Bug fixes and improvements", "https://github.com/J3vb/OwnCord/releases/tag/v1.2.0",
 		"https://github.com/J3vb/OwnCord/releases/download/v1.2.0")
@@ -101,6 +132,44 @@ func TestCheckForUpdate_NewerVersionAvailable(t *testing.T) {
 	} else if info.DownloadURL != "" {
 		t.Error("expected empty DownloadURL on unsupported GOOS")
 	}
+	if info.SignatureURL == "" {
+		t.Error("expected non-empty SignatureURL")
+	}
+	if info.ManifestURL == "" {
+		t.Error("expected non-empty ManifestURL")
+	}
+	if info.ManifestSignatureURL == "" {
+		t.Error("expected non-empty ManifestSignatureURL")
+	}
+	if !info.RequiredAssetsPresent {
+		t.Error("expected RequiredAssetsPresent=true")
+	}
+}
+
+func TestCheckForUpdate_MissingRequiredAssetsSuppressesUpdate(t *testing.T) {
+	release := ghRelease{
+		TagName: "v1.2.0",
+		Body:    "Broken release",
+		HTMLURL: "https://github.com/J3vb/OwnCord/releases/tag/v1.2.0",
+		Assets: []ghAsset{
+			{Name: "chatserver.exe", BrowserDownloadURL: "https://github.com/J3vb/OwnCord/releases/download/v1.2.0/chatserver.exe"},
+			{Name: "checksums.sha256", BrowserDownloadURL: "https://github.com/J3vb/OwnCord/releases/download/v1.2.0/checksums.sha256"},
+		},
+	}
+	srv := newTestServer(t, release, http.StatusOK)
+	defer srv.Close()
+
+	u := newTestUpdater(srv.URL, "1.0.0")
+	info, err := u.CheckForUpdate(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if info.UpdateAvailable {
+		t.Fatal("expected UpdateAvailable=false for incomplete release")
+	}
+	if info.RequiredAssetsPresent {
+		t.Fatal("expected RequiredAssetsPresent=false for incomplete release")
+	}
 }
 
 func TestCheckForUpdate_UpToDate(t *testing.T) {
@@ -427,6 +496,46 @@ func TestExtractChatserverFromTarGz(t *testing.T) {
 	}
 }
 
+func TestAssetFilenameFromURL(t *testing.T) {
+	got, err := assetFilenameFromURL("https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe")
+	if err != nil {
+		t.Fatalf("assetFilenameFromURL: %v", err)
+	}
+	if got != "chatserver.exe" {
+		t.Errorf("assetFilenameFromURL = %q, want chatserver.exe", got)
+	}
+}
+
+func TestDefaultServerSignaturePublicKey_DiffersFromTauriUpdaterKey(t *testing.T) {
+	tauriConfigPath := filepath.Clean(filepath.Join("..", "..", "Client", "tauri-client", "src-tauri", "tauri.conf.json"))
+	raw, err := os.ReadFile(tauriConfigPath)
+	if err != nil {
+		t.Fatalf("ReadFile(%s): %v", tauriConfigPath, err)
+	}
+
+	var cfg struct {
+		Plugins struct {
+			Updater struct {
+				PubKey string `json:"pubkey"`
+			} `json:"updater"`
+		} `json:"plugins"`
+	}
+	if err := json.Unmarshal(raw, &cfg); err != nil {
+		t.Fatalf("Unmarshal tauri.conf.json: %v", err)
+	}
+
+	if cfg.Plugins.Updater.PubKey == defaultServerSignaturePublicKey {
+		t.Fatalf("server updater signing key must differ from tauri.conf.json updater pubkey")
+	}
+}
+
+func TestDefaultServerSignaturePublicKey_Parseable(t *testing.T) {
+	u := NewUpdater("1.0.0", "", "J3vb", "OwnCord")
+	if _, err := u.serverSignaturePublicKey(); err != nil {
+		t.Fatalf("serverSignaturePublicKey: %v", err)
+	}
+}
+
 // ─── SetBaseURL ──────────────────────────────────────────────────────────────
 
 func TestSetBaseURL(t *testing.T) {
@@ -554,6 +663,10 @@ func testDownloadAndVerifySuccessWindows(t *testing.T) {
 	content := []byte("real binary content for verification")
 	hash := sha256.Sum256(content)
 	checksumHex := hex.EncodeToString(hash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	signature := signTestAsset(t, privateKey, content)
+	manifest := []byte(`{"version":"v1.0.0","asset":"chatserver.exe","sha256":"` + checksumHex + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
 
 	mux := http.NewServeMux()
 	mux.HandleFunc("/download/chatserver.exe", func(w http.ResponseWriter, r *http.Request) {
@@ -562,24 +675,35 @@ func testDownloadAndVerifySuccessWindows(t *testing.T) {
 	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
 		_, _ = fmt.Fprintf(w, "%s  chatserver.exe\n", checksumHex)
 	})
+	mux.HandleFunc("/download/chatserver.exe.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(append(signature, []byte("\r\n")...))
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
 	srv := httptest.NewServer(mux)
 	defer srv.Close()
 
 	tmpDir := t.TempDir()
-	dest := filepath.Join(tmpDir, "chatserver.exe")
+	dest := filepath.Join(tmpDir, "chatserver.exe.new")
 
-	u := NewUpdater("1.0.0", "", "J3vb", "OwnCord")
 	u.baseURL = srv.URL
 
 	downloadURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe"
 	checksumURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256"
+	signatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe.sig"
+	manifestURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json"
+	manifestSignatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig"
 
 	// Override HTTP client to route GitHub URLs to our test server.
 	u.httpClient = &http.Client{
 		Transport: &rewriteTransport{srv.URL},
 	}
 
-	err := u.DownloadAndVerify(context.Background(), downloadURL, checksumURL, dest)
+	err := u.DownloadAndVerify(context.Background(), "v1.0.0", downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL, dest)
 	if err != nil {
 		t.Fatalf("DownloadAndVerify: %v", err)
 	}
@@ -595,6 +719,9 @@ func testDownloadAndVerifySuccessLinux(t *testing.T) {
 	tgz := mustBuildChatserverTarGz(t, inner)
 	hash := sha256.Sum256(tgz)
 	checksumHex := hex.EncodeToString(hash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	manifest := []byte(`{"version":"v1.0.0","asset":"chatserver-linux-amd64.tar.gz","sha256":"` + checksumHex + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
 
 	mux := http.NewServeMux()
 	mux.HandleFunc("/download/chatserver-linux-amd64.tar.gz", func(w http.ResponseWriter, r *http.Request) {
@@ -603,23 +730,36 @@ func testDownloadAndVerifySuccessLinux(t *testing.T) {
 	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
 		_, _ = fmt.Fprintf(w, "%s  linux/chatserver-linux-amd64.tar.gz\n", checksumHex)
 	})
+	mux.HandleFunc("/download/chatserver-linux-amd64.tar.gz.sig", func(w http.ResponseWriter, r *http.Request) {
+		// Linux tar.gz does not have a detached binary sig; return empty to satisfy URL validation.
+		// The signing flow only applies the manifest; the binary sig slot is unused on Linux.
+		w.WriteHeader(http.StatusOK)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
 	srv := httptest.NewServer(mux)
 	defer srv.Close()
 
 	tmpDir := t.TempDir()
 	dest := filepath.Join(tmpDir, "chatserver")
 
-	u := NewUpdater("1.0.0", "", "J3vb", "OwnCord")
 	u.baseURL = srv.URL
 
 	downloadURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver-linux-amd64.tar.gz"
 	checksumURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256"
+	signatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver-linux-amd64.tar.gz.sig"
+	manifestURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json"
+	manifestSignatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig"
 
 	u.httpClient = &http.Client{
 		Transport: &rewriteTransport{srv.URL},
 	}
 
-	err := u.DownloadAndVerify(context.Background(), downloadURL, checksumURL, dest)
+	err := u.DownloadAndVerify(context.Background(), "v1.0.0", downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL, dest)
 	if err != nil {
 		t.Fatalf("DownloadAndVerify: %v", err)
 	}
@@ -661,7 +801,7 @@ func mustBuildChatserverTarGz(t *testing.T, inner []byte) []byte {
 
 func TestDownloadAndVerify_InvalidDownloadURL(t *testing.T) {
 	u := NewUpdater("1.0.0", "", "J3vb", "OwnCord")
-	err := u.DownloadAndVerify(context.Background(), "https://evil.com/file", "https://evil.com/sum", "/tmp/out")
+	err := u.DownloadAndVerify(context.Background(), "v1.0.0", "https://evil.com/file", "https://evil.com/sum", "https://evil.com/file.sig", "https://evil.com/manifest.json", "https://evil.com/manifest.json.sig", "/tmp/out")
 	if err == nil {
 		t.Error("DownloadAndVerify should reject invalid download URL")
 	}
@@ -669,8 +809,8 @@ func TestDownloadAndVerify_InvalidDownloadURL(t *testing.T) {
 
 func TestDownloadAndVerify_InvalidChecksumURL(t *testing.T) {
 	u := NewUpdater("1.0.0", "", "J3vb", "OwnCord")
-	downloadURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/" + serverDownloadAssetName(runtime.GOOS)
-	err := u.DownloadAndVerify(context.Background(), downloadURL, "https://evil.com/sum", "/tmp/out")
+	downloadURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe"
+	err := u.DownloadAndVerify(context.Background(), "v1.0.0", downloadURL, "https://evil.com/sum", "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe.sig", "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json", "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig", "/tmp/out")
 	if err == nil {
 		t.Error("DownloadAndVerify should reject invalid checksum URL")
 	}
@@ -690,6 +830,12 @@ func TestDownloadAndVerify_ChecksumMismatch(t *testing.T) {
 func testDownloadAndVerifyChecksumMismatchWindows(t *testing.T) {
 	content := []byte("binary content")
 	wrongChecksum := "0000000000000000000000000000000000000000000000000000000000000000"
+	actualHash := sha256.Sum256(content)
+	actualChecksum := hex.EncodeToString(actualHash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	signature := signTestAsset(t, privateKey, content)
+	manifest := []byte(`{"version":"v1.0.0","asset":"chatserver.exe","sha256":"` + actualChecksum + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
 
 	mux := http.NewServeMux()
 	mux.HandleFunc("/download/chatserver.exe", func(w http.ResponseWriter, r *http.Request) {
@@ -698,19 +844,30 @@ func testDownloadAndVerifyChecksumMismatchWindows(t *testing.T) {
 	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
 		_, _ = fmt.Fprintf(w, "%s  chatserver.exe\n", wrongChecksum)
 	})
+	mux.HandleFunc("/download/chatserver.exe.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(signature)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
 	srv := httptest.NewServer(mux)
 	defer srv.Close()
 
 	tmpDir := t.TempDir()
 	dest := filepath.Join(tmpDir, "chatserver.exe")
 
-	u := NewUpdater("1.0.0", "", "J3vb", "OwnCord")
 	u.httpClient = &http.Client{Transport: &rewriteTransport{srv.URL}}
 
 	downloadURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe"
 	checksumURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256"
+	signatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe.sig"
+	manifestURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json"
+	manifestSignatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig"
 
-	err := u.DownloadAndVerify(context.Background(), downloadURL, checksumURL, dest)
+	err := u.DownloadAndVerify(context.Background(), "v1.0.0", downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL, dest)
 	if err == nil {
 		t.Error("DownloadAndVerify should fail on checksum mismatch")
 	}
@@ -724,6 +881,11 @@ func testDownloadAndVerifyChecksumMismatchWindows(t *testing.T) {
 func testDownloadAndVerifyChecksumMismatchLinux(t *testing.T) {
 	tgz := mustBuildChatserverTarGz(t, []byte("x"))
 	wrongChecksum := "0000000000000000000000000000000000000000000000000000000000000000"
+	actualHash := sha256.Sum256(tgz)
+	actualChecksum := hex.EncodeToString(actualHash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	manifest := []byte(`{"version":"v1.0.0","asset":"chatserver-linux-amd64.tar.gz","sha256":"` + actualChecksum + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
 
 	mux := http.NewServeMux()
 	mux.HandleFunc("/download/chatserver-linux-amd64.tar.gz", func(w http.ResponseWriter, r *http.Request) {
@@ -732,19 +894,30 @@ func testDownloadAndVerifyChecksumMismatchLinux(t *testing.T) {
 	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
 		_, _ = fmt.Fprintf(w, "%s  linux/chatserver-linux-amd64.tar.gz\n", wrongChecksum)
 	})
+	mux.HandleFunc("/download/chatserver-linux-amd64.tar.gz.sig", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
 	srv := httptest.NewServer(mux)
 	defer srv.Close()
 
 	tmpDir := t.TempDir()
 	dest := filepath.Join(tmpDir, "chatserver")
 
-	u := NewUpdater("1.0.0", "", "J3vb", "OwnCord")
 	u.httpClient = &http.Client{Transport: &rewriteTransport{srv.URL}}
 
 	downloadURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver-linux-amd64.tar.gz"
 	checksumURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256"
+	signatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver-linux-amd64.tar.gz.sig"
+	manifestURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json"
+	manifestSignatureURL := "https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig"
 
-	err := u.DownloadAndVerify(context.Background(), downloadURL, checksumURL, dest)
+	err := u.DownloadAndVerify(context.Background(), "v1.0.0", downloadURL, checksumURL, signatureURL, manifestURL, manifestSignatureURL, dest)
 	if err == nil {
 		t.Error("DownloadAndVerify should fail on checksum mismatch")
 	}
@@ -754,6 +927,198 @@ func testDownloadAndVerifyChecksumMismatchLinux(t *testing.T) {
 	}
 }
 
+func TestDownloadAndVerify_MissingSignature(t *testing.T) {
+	content := []byte("real binary content for verification")
+	hash := sha256.Sum256(content)
+	checksumHex := hex.EncodeToString(hash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	manifest := []byte(`{"version":"v1.0.0","asset":"chatserver.exe","sha256":"` + checksumHex + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/download/chatserver.exe", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(content)
+	})
+	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = fmt.Fprintf(w, "%s  chatserver.exe\n", checksumHex)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
+	srv := httptest.NewServer(mux)
+	defer srv.Close()
+
+	tmpDir := t.TempDir()
+	dest := filepath.Join(tmpDir, "chatserver.exe")
+
+	u.httpClient = &http.Client{Transport: &rewriteTransport{srv.URL}}
+
+	err := u.DownloadAndVerify(
+		context.Background(),
+		"v1.0.0",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe.sig",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig",
+		dest,
+	)
+	if err == nil {
+		t.Fatal("DownloadAndVerify should fail when signature asset is missing")
+	}
+}
+
+func TestDownloadAndVerify_InvalidSignature(t *testing.T) {
+	content := []byte("real binary content for verification")
+	otherContent := []byte("tampered bytes")
+	hash := sha256.Sum256(content)
+	checksumHex := hex.EncodeToString(hash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	signature := signTestAsset(t, privateKey, otherContent)
+	manifest := []byte(`{"version":"v1.0.0","asset":"chatserver.exe","sha256":"` + checksumHex + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/download/chatserver.exe", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(content)
+	})
+	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = fmt.Fprintf(w, "%s  chatserver.exe\n", checksumHex)
+	})
+	mux.HandleFunc("/download/chatserver.exe.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(signature)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
+	srv := httptest.NewServer(mux)
+	defer srv.Close()
+
+	tmpDir := t.TempDir()
+	dest := filepath.Join(tmpDir, "chatserver.exe")
+
+	u.httpClient = &http.Client{Transport: &rewriteTransport{srv.URL}}
+	err := u.DownloadAndVerify(
+		context.Background(),
+		"v1.0.0",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe.sig",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig",
+		dest,
+	)
+	if err == nil {
+		t.Fatal("DownloadAndVerify should fail on invalid signature")
+	}
+	if _, statErr := os.Stat(dest); !os.IsNotExist(statErr) {
+		t.Error("file should be removed after signature verification failure")
+	}
+}
+
+func TestDownloadAndVerify_MalformedSignature(t *testing.T) {
+	content := []byte("real binary content for verification")
+	hash := sha256.Sum256(content)
+	checksumHex := hex.EncodeToString(hash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	manifest := []byte(`{"version":"v1.0.0","asset":"chatserver.exe","sha256":"` + checksumHex + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/download/chatserver.exe", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(content)
+	})
+	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = fmt.Fprintf(w, "%s  chatserver.exe\n", checksumHex)
+	})
+	mux.HandleFunc("/download/chatserver.exe.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write([]byte("not-a-valid-signature"))
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
+	srv := httptest.NewServer(mux)
+	defer srv.Close()
+
+	tmpDir := t.TempDir()
+	dest := filepath.Join(tmpDir, "chatserver.exe")
+
+	u.httpClient = &http.Client{Transport: &rewriteTransport{srv.URL}}
+	err := u.DownloadAndVerify(
+		context.Background(),
+		"v1.0.0",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe.sig",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig",
+		dest,
+	)
+	if err == nil {
+		t.Fatal("DownloadAndVerify should fail on malformed signature")
+	}
+	if _, statErr := os.Stat(dest); !os.IsNotExist(statErr) {
+		t.Error("file should be removed after malformed signature")
+	}
+}
+
+func TestDownloadAndVerify_ManifestVersionMismatch(t *testing.T) {
+	content := []byte("real binary content for verification")
+	hash := sha256.Sum256(content)
+	checksumHex := hex.EncodeToString(hash[:])
+	u, privateKey := newSignedTestUpdater(t, "", "1.0.0")
+	signature := signTestAsset(t, privateKey, content)
+	manifest := []byte(`{"version":"v0.9.0","asset":"chatserver.exe","sha256":"` + checksumHex + `"}`)
+	manifestSignature := signTestAsset(t, privateKey, manifest)
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/download/chatserver.exe", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(content)
+	})
+	mux.HandleFunc("/download/checksums.sha256", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = fmt.Fprintf(w, "%s  chatserver.exe\n", checksumHex)
+	})
+	mux.HandleFunc("/download/chatserver.exe.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(signature)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifest)
+	})
+	mux.HandleFunc("/download/server-update-manifest.json.sig", func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write(manifestSignature)
+	})
+	srv := httptest.NewServer(mux)
+	defer srv.Close()
+
+	dest := filepath.Join(t.TempDir(), "chatserver.exe")
+	u.httpClient = &http.Client{Transport: &rewriteTransport{srv.URL}}
+	err := u.DownloadAndVerify(
+		context.Background(),
+		"v1.0.0",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/checksums.sha256",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/chatserver.exe.sig",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json",
+		"https://github.com/J3vb/OwnCord/releases/download/v1.0.0/server-update-manifest.json.sig",
+		dest,
+	)
+	if err == nil {
+		t.Fatal("DownloadAndVerify should fail on mismatched signed manifest version")
+	}
+	if _, statErr := os.Stat(dest); !os.IsNotExist(statErr) {
+		t.Error("file should be removed after manifest verification failure")
+	}
+}
+
 // rewriteTransport rewrites GitHub release URLs to a local test server.
 type rewriteTransport struct {
 	target string
diff --git a/Server/ws/export_test.go b/Server/ws/export_test.go
index 744feb69..f246be60 100644
--- a/Server/ws/export_test.go
+++ b/Server/ws/export_test.go
@@ -206,5 +206,5 @@ func (h *Hub) HandleWebhookParticipantLeftForTest(userID int64, channelID int64,
 			Name: roomName,
 		},
 	}
-	h.handleWebhookParticipantLeft(event)
+	h.handleWebhookParticipantLeft(context.Background(), event)
 }
diff --git a/Server/ws/livekit_webhook.go b/Server/ws/livekit_webhook.go
index 83787939..5ff3e774 100644
--- a/Server/ws/livekit_webhook.go
+++ b/Server/ws/livekit_webhook.go
@@ -80,9 +80,9 @@ func (h *Hub) NewLiveKitWebhookHandler(apiKey, apiSecret string) http.HandlerFun
 
 		switch event.Event {
 		case "participant_joined":
-			h.handleWebhookParticipantJoined(&event)
+			h.handleWebhookParticipantJoined(r.Context(), &event)
 		case "participant_left":
-			h.handleWebhookParticipantLeft(&event)
+			h.handleWebhookParticipantLeft(r.Context(), &event)
 		default:
 			slog.Debug("livekit webhook: unhandled event", "event", event.Event)
 		}
@@ -122,7 +122,7 @@ func parseRoomChannelID(roomName string) (int64, error) {
 	return strconv.ParseInt(roomName[8:], 10, 64)
 }
 
-func (h *Hub) handleWebhookParticipantJoined(event *livekit.WebhookEvent) {
+func (h *Hub) handleWebhookParticipantJoined(_ context.Context, event *livekit.WebhookEvent) {
 	p := event.GetParticipant()
 	room := event.GetRoom()
 	if p == nil || room == nil {
@@ -157,7 +157,7 @@ func (h *Hub) handleWebhookParticipantJoined(event *livekit.WebhookEvent) {
 			slog.Warn("livekit webhook: rogue participant_joined — no matching voice state, removing",
 				"user_id", userID, "channel_id", channelID)
 			if h.livekit != nil {
-				if rmErr := h.livekit.RemoveParticipant(channelID, userID, joinToken); rmErr != nil {
+				if rmErr := h.livekit.RemoveParticipant(channelID, userID, joinToken); rmErr != nil { //nolint:contextcheck // RemoveParticipant manages its own timeout context
 					slog.Error("livekit webhook: failed to remove rogue participant",
 						"error", rmErr, "user_id", userID, "channel_id", channelID)
 				}
@@ -170,7 +170,7 @@ func (h *Hub) handleWebhookParticipantJoined(event *livekit.WebhookEvent) {
 				"user_id", userID, "channel_id", channelID,
 				"expected_token", state.JoinedAt, "got_token", joinToken)
 			if h.livekit != nil {
-				if rmErr := h.livekit.RemoveParticipant(channelID, userID, joinToken); rmErr != nil {
+				if rmErr := h.livekit.RemoveParticipant(channelID, userID, joinToken); rmErr != nil { //nolint:contextcheck // RemoveParticipant manages its own timeout context
 					slog.Error("livekit webhook: failed to remove stale participant",
 						"error", rmErr, "user_id", userID, "channel_id", channelID)
 				}
@@ -180,7 +180,7 @@ func (h *Hub) handleWebhookParticipantJoined(event *livekit.WebhookEvent) {
 	}
 }
 
-func (h *Hub) handleWebhookParticipantLeft(event *livekit.WebhookEvent) {
+func (h *Hub) handleWebhookParticipantLeft(ctx context.Context, event *livekit.WebhookEvent) {
 	p := event.GetParticipant()
 	room := event.GetRoom()
 	if p == nil || room == nil {
@@ -220,7 +220,7 @@ func (h *Hub) handleWebhookParticipantLeft(event *livekit.WebhookEvent) {
 				c.clearVoiceState()
 
 				if h.db != nil {
-					if err := leaveVoiceChannelWithRetry(context.Background(), h, userID, channelID, joinToken); err != nil {
+					if err := leaveVoiceChannelWithRetry(ctx, h, userID, channelID, joinToken); err != nil {
 						slog.Error("livekit webhook: LeaveVoiceChannel exhausted retries",
 							"error", err, "user_id", userID, "channel_id", channelID)
 					}
diff --git a/Server/ws/serve.go b/Server/ws/serve.go
index f277fb70..2b5e731c 100644
--- a/Server/ws/serve.go
+++ b/Server/ws/serve.go
@@ -232,7 +232,7 @@ func (h *Hub) handleFreshConnect(
 			// different identity and won't be removed. Use a hub-stop-aware
 			// context to avoid goroutine leaks on shutdown.
 			staleChID, staleUserID, staleJoinToken := vs.ChannelID, c.userID, vs.JoinedAt
-			go func() {
+			go func() { //nolint:contextcheck // goroutine intentionally detaches from request context; lifecycle managed via h.stop
 				select {
 				case <-h.stop:
 					return
diff --git a/docs/deployment.md b/docs/deployment.md
index 178ce2ba..23fe0853 100644
--- a/docs/deployment.md
+++ b/docs/deployment.md
@@ -183,8 +183,10 @@ Restoring replaces the live database file. A pre-restore safety backup is create
 The server checks GitHub Releases for updates:
 - Compares semver versions
 - Results are cached for 1 hour
-- Downloads `chatserver.exe` with SHA256 checksum verification
-- On restart, the old binary is cleaned up
+- Downloads `chatserver.exe` with detached Ed25519/minisign signature verification
+- Verifies a signed `server-update-manifest.json` that binds the binary hash to the release version
+- Cross-checks the binary SHA256 against `checksums.sha256`
+- On restart, the current binary is rotated to `chatserver.exe.old` before the new binary takes its place
 
 Set `github.token` in config for higher API rate limits (5000/hr vs 60/hr unauthenticated).
 
diff --git a/docs/security.md b/docs/security.md
index 797dda2b..b54cfe7d 100644
--- a/docs/security.md
+++ b/docs/security.md
@@ -83,7 +83,7 @@ The Tauri desktop client implements the following security measures:
 
 ## Known Limitations
 
-- No code signing yet -- binaries are verified via SHA256 checksums only
+- Server auto-updates depend on a dedicated pinned minisign/Ed25519 server release key in [Server/updater/server_update_public_key.txt](Server/updater/server_update_public_key.txt) and a signed release manifest that binds the shipped binary hash to the release version; Windows Authenticode/SmartScreen code signing is still separate work
 - The Tenor API key is hardcoded (Google's public anonymous key) — consider build-time injection for production
 - CSP `connect-src` allows `https:` to any host (necessary for self-hosted server URLs not known at build time)