diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1e2d2d9..c593dac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,24 @@ By: Codex (GPT-5)
 | 28.12.2025 | 🏗️ Planning | ID: Update-Format festgelegt (JSON + tar.gz). By: Codex (GPT-5) |
 | 28.12.2025 | 🏗️ Planning | ID: Update-Service URL auf update.wlkns.org festgelegt. By: Codex (GPT-5) |
 | 28.12.2025 | 🏗️ Planning | ID: EPIC_000009 Update Webservice (External Team) dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | 🏗️ Planning | ID: TASK_000027-TASK_000029 fuer EPIC_000008 ausgearbeitet. By: Codex (GPT-5) |
+| 28.12.2025 | ⚙️ Code | ID: Update-Config Keys in Settings/ENV/README definiert. By: Codex (GPT-5) |
+| 28.12.2025 | 📝 Req | ID: Update-Flow fuer Client dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | 📝 Req | ID: Update-Flow Prototyp dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | 📝 Req | ID: Update-Status-Schema dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | ⚙️ Code | ID: Update-Status-URL und Report im Client-Prototyp. By: Codex (GPT-5) |
+| 28.12.2025 | 🏗️ Planning | ID: US_000029-US_000032 fuer Update-UI dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | 🏗️ Planning | ID: US_000033 Rollback-UI dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | 🏗️ Planning | ID: Update-UI Anforderungen um Backup-Voraussetzung ergaenzt. By: Codex (GPT-5) |
+| 28.12.2025 | 🏗️ Planning | ID: TASK_000030-TASK_000034 fuer Update-UI ausgearbeitet. By: Codex (GPT-5) |
+| 28.12.2025 | 📝 Req | ID: Update-API Endpunkte dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | 📝 Req | ID: Update-Status/Log Dateien dokumentiert. By: Codex (GPT-5) |
+| 28.12.2025 | ⚙️ Code | ID: Update-Client Prototyp-Skript hinzugefuegt. By: Codex (GPT-5) |
+| 29.12.2025 | ⚙️ Code | ID: Update-Backend Logik implementiert (backend/update.py). By: Codex (GPT-5) |
+| 29.12.2025 | ⚙️ Code | ID: Update-Models und Settings erweitert (Models, Status-File Paths). By: Codex (GPT-5) |
+| 29.12.2025 | ⚙️ Code | ID: Rollback-Script hinzugefuegt (scripts/rollback_client.sh). By: Codex (GPT-5) |
+| 30.12.2025 | ⚙️ Code | ID: Update-API Endpunkte implementiert (GET /update/status, POST /update/check, POST /update/apply, POST /update/rollback, GET /update/logs). By: Claude Sonnet 4.5 |
+| 30.12.2025 | ⚙️ Code | ID: Update-UI im Web-Frontend implementiert (Status-Anzeige, Check/Apply/Rollback Buttons, Logs-Viewer). By: Claude Sonnet 4.5 |
 
 ---
 ## Legende
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..ff9e637
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,145 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Safe Kiddo Daemon (SKD) is a FastAPI-based service for managing local user accounts on kids' laptops. It provides account locking/unlocking with countdown notifications, optional sound alerts, and shutdown capabilities. The service exposes a REST API with bearer token auth (PAM or OIDC) and serves a minimal web UI.
+
+## Commands
+
+### Development
+```bash
+# Run the service manually (uses .venv, binds to 0.0.0.0:80)
+./scripts/run.sh
+
+# Install service and dependencies
+sudo make install
+
+# Service management
+sudo make up      # Start service
+sudo make down    # Stop service
+sudo make update  # Pull latest from git, reinstall deps, restart
+
+# Generate/set API token
+make token
+
+# Health check (requires token)
+make healthcheck
+```
+
+### Installation & Deployment
+```bash
+# Full install (creates service user, venv, systemd unit, PAM config)
+sudo ./scripts/install.sh
+
+# Deploy to remote host (requires deploy_hosts.yml)
+./scripts/deploy.sh <host-name>
+
+# Manual update on target
+ssh user@target 'cd /opt/sk && ./scripts/update.sh'
+```
+
+### Testing
+```bash
+# Python syntax validation
+python -m py_compile backend/*.py
+
+# Run specific tests (no formal test runner yet; tests/ is empty)
+# Use curl for API testing:
+token=$(curl -s -X POST -H "Content-Type: application/json" \
+  -d '{"username":"root","password":"..."}' \
+  http://localhost/login | jq -r .token)
+curl -H "Authorization: Bearer $token" http://localhost/users
+```
+
+## Architecture
+
+### Core Structure
+- `backend/`: FastAPI application
+  - `app.py`: Main FastAPI app with route handlers
+  - `actions.py`: User management actions (lock/unlock, notifications, shutdown logic)
+  - `auth.py`: PAM authentication, JWT tokens, user/group authorization checks
+  - `oidc.py`: OIDC client (dynamic discovery, token exchange, claims validation)
+  - `update.py`: Update client logic (check/status/logs, triggers async update/rollback scripts)
+  - `settings.py`: Environment-based configuration (Settings class, singleton via lru_cache)
+  - `models.py`: Pydantic models for API requests/responses
+  - `templates/`: Jinja2 templates for web UI
+- `scripts/`: Deployment and lifecycle scripts
+  - `install.sh`: System setup (user, venv, systemd, PAM config)
+  - `run.sh`: Manual service start
+  - `update.sh`: Local git pull and service restart
+  - `update_client.sh`: Full update flow with backup/rollback
+  - `rollback_client.sh`: Restore from backup if update fails
+  - `deploy.sh`: SSH-based deployment to remote hosts
+  - `register_oidc_client.sh`: OIDC dynamic client registration helper
+- `sk.sh`: Legacy bash script (CLI fallback for direct SSH use)
+- `src/`: Hexagonal architecture skeleton (core/ports/adapters/ui) - currently empty placeholders
+- `docs/`: Detailed specs for OIDC validation, update API, status/log formats
+- `Makefile`: Convenience targets for install, service control, updates, token management
+
+### Key Architectural Patterns
+
+**Dual Authentication**: PAM-based local auth (root/sudo users) is always available; OIDC is optional if `SKD_OIDC_ISSUER`, `SKD_OIDC_CLIENT_ID`, and `SKD_OIDC_CLIENT_SECRET` are configured. Both modes issue JWT bearer tokens.
+
+**Settings Management**: All config via environment variables (loaded from `/etc/skd/env` in production). `settings.py` provides a singleton `Settings` instance via `get_settings()` using `lru_cache`. FastAPI dependencies inject settings into route handlers.
+
+**Action Execution**: `actions.py` wraps all privileged operations (usermod, pkill, shutdown) via `_run()` helper. Dry-run mode (`SKD_DRY_RUN=true`) logs commands without executing them.
+
+**Update Flow**: `update.py` checks remote update service for new versions, writes status to JSON files, and triggers async scripts (`update_client.sh`, `rollback_client.sh`) that create backups, apply updates, and handle rollbacks on failure.
+
+**Authorization**: `auth.py` checks both user allowlists (`SKD_AUTH_ALLOWED_USERS`) and group membership (`SKD_AUTH_ALLOWED_GROUPS`, defaults to `sudo`). UID 0 (root) always allowed for PAM. OIDC validates against `preferred_username`, `email`, or `sub` claims.
+
+**Manageable Users**: Only system users with UID >= 1000, real shells (not nologin/false), and optional allowlist (`SKD_ALLOWED_USERS`) are exposed via API. Root accounts are never manageable.
+
+## Configuration
+
+Deployment config lives in `/etc/skd/env` (see `env.example` in repo root):
+- `SKD_AUTH_SECRET`: HMAC secret for JWT signing (must be strong in production)
+- `SKD_AUTH_ALLOWED_USERS`: Comma-separated user allowlist (for login and OIDC claims)
+- `SKD_AUTH_ALLOWED_GROUPS`: Groups whose members may log in (PAM only, default `sudo`)
+- `SKD_AUTH_PAM_SERVICE`: PAM service name (Ubuntu/Debian use `skd`, others may use `login`)
+- `SKD_OIDC_*`: OIDC provider config (ISSUER, CLIENT_ID, CLIENT_SECRET, REDIRECT_URI, SCOPES)
+- `SKD_ALLOWED_USERS`: Comma-separated list of manageable system accounts (optional)
+- `SKD_DRY_RUN`: If `true`, logs all privileged commands without executing
+- `SKD_UPDATE_*`: Update service URL, token, interval, status/log file paths
+
+## Important Workflows
+
+### Disable User Flow
+1. API call to `/users/{username}/disable` with optional `{countdown, sound, message}`
+2. `actions.disable_user()` locks account via `usermod -L`
+3. If user logged in: sends desktop notifications, plays sound (if enabled), countdown loop with periodic reminders
+4. Terminates sessions via `pkill -KILL -u`
+5. Triggers `shutdown now` only if user was logged in
+
+### OIDC Login Flow
+1. User accesses `/login/oidc/start` → redirected to provider with state cookie
+2. Provider redirects to `/login/oidc/callback` with code + state
+3. Validates state, exchanges code for tokens, extracts username from claims
+4. Issues JWT session cookie if user in allowlist
+
+### Update Flow
+1. `check_update()` polls remote update service for latest manifest (version, artifact_url, sha256)
+2. `start_update()` writes "in_progress" status, launches `update_client.sh` in background
+3. Script creates backup, downloads artifact, verifies checksum, installs, restarts service
+4. On failure: `rollback_client.sh` restores from backup
+5. Status/logs written to JSON files at `SKD_UPDATE_STATUS_FILE` and `SKD_UPDATE_LOG_FILE`
+
+## Security Considerations
+
+- Service runs as root by default (required for PAM, usermod, pkill, shutdown). Limit exposure via firewall.
+- Set strong `SKD_AUTH_SECRET` and rotate by changing value + restarting service.
+- Restrict API/Web UI to LAN/VPN; consider mTLS or IP allowlisting.
+- `skd` user/group created by install script; consider sudoers rules to limit privileges to specific commands.
+- OIDC redirect URI must match exactly (no wildcards); re-register client if host/port changes.
+- Validate TLS certificates in production; self-signed certs require CA trust or fallback to PAM.
+
+## Notes
+
+- Legacy `sk.sh` remains for emergency CLI fallback; API is preferred for all operations.
+- `src/` hexagonal architecture skeleton is currently unused; logic lives in `backend/`.
+- `tests/` directory exists but is empty; use manual curl-based API testing.
+- Both German and English comments exist in code; favor English going forward.
+- Deployment via `deploy.sh` supports both YAML (`deploy_hosts.yml`) and JSON host configs.
+- PAM service file (`/etc/pam.d/skd`) created by `scripts/install.sh` on Ubuntu/Debian; other distros may need manual setup.
diff --git a/README.md b/README.md
index 1563bac..1ea6ed8 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,13 @@ Set in `/etc/skd/env` (see `env.example`):
 - `SKD_DEFAULT_COUNTDOWN`, `SKD_DEFAULT_SOUND`, `SKD_NOTIFY_TIMEOUT`: behavior defaults.
 - `SKD_DRY_RUN=true` to test without real account changes or shutdown.
 - `SKD_SOUND_PLAYER`/`SKD_SOUND_FILE`, `SKD_NOTIFY_SEND_PATH` if defaults differ.
+- Update client:
+  - `SKD_UPDATE_URL` (default `https://update.wlkns.org`)
+  - `SKD_UPDATE_TOKEN` (API token for update service)
+  - `SKD_UPDATE_INTERVAL` (seconds; default 3600)
+  - `SKD_UPDATE_STATUS_URL` (default `https://update.wlkns.org/status`)
+  - `SKD_UPDATE_STATUS_FILE` (default `/var/lib/skd/update_status.json`)
+  - `SKD_UPDATE_LOG_FILE` (default `/var/lib/skd/update_logs.jsonl`)
 Notes:
 - `./scripts/install.sh` will create `/etc/skd/env` from `env.example` if missing (edit afterwards) and ensure the `skd` service user/group exist.
 
diff --git a/backend/app.py b/backend/app.py
index b8e83e9..6dc1fa9 100644
--- a/backend/app.py
+++ b/backend/app.py
@@ -15,9 +15,20 @@ from backend.auth import (
     issue_token,
     list_manageable_users,
 )
-from backend.models import ActionRequest, ActionResponse, LoginRequest, LoginResponse, UserStatus
+from backend.models import (
+    ActionRequest,
+    ActionResponse,
+    LoginRequest,
+    LoginResponse,
+    UpdateActionResponse,
+    UpdateCheckResponse,
+    UpdateLogEntry,
+    UpdateStatus,
+    UserStatus,
+)
 from backend.oidc import OIDCClient, OIDCError
 from backend.settings import Settings, get_settings
+from backend import update
 
 logging.basicConfig(
     level=logging.INFO,
@@ -219,6 +230,67 @@ def enable_user(
     )
 
 
+@app.get("/update/status", response_model=UpdateStatus, dependencies=[Depends(get_current_admin)])
+def update_status(settings: Settings = Depends(get_settings)) -> UpdateStatus:
+    status_data = update.get_status(settings)
+    return UpdateStatus(**status_data)
+
+
+@app.post("/update/check", response_model=UpdateCheckResponse, dependencies=[Depends(get_current_admin)])
+def update_check(settings: Settings = Depends(get_settings)) -> UpdateCheckResponse:
+    try:
+        check_data = update.check_update(settings)
+    except Exception as exc:
+        logger.exception("Update check failed")
+        raise HTTPException(
+            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+            detail=f"Update check failed: {str(exc)}",
+        ) from exc
+    return UpdateCheckResponse(**check_data)
+
+
+@app.post("/update/apply", response_model=UpdateActionResponse, dependencies=[Depends(get_current_admin)])
+def update_apply(
+    settings: Settings = Depends(get_settings),
+    payload: dict | None = Body(default=None),
+) -> UpdateActionResponse:
+    version = payload.get("version") if payload else None
+    try:
+        update.start_update(settings, version)
+    except Exception as exc:
+        logger.exception("Failed to start update")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"Failed to start update: {str(exc)}",
+        ) from exc
+    return UpdateActionResponse(started=True, message="Update started")
+
+
+@app.post("/update/rollback", response_model=UpdateActionResponse, dependencies=[Depends(get_current_admin)])
+def update_rollback(settings: Settings = Depends(get_settings)) -> UpdateActionResponse:
+    try:
+        update.start_rollback(settings)
+    except Exception as exc:
+        logger.exception("Failed to start rollback")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"Failed to start rollback: {str(exc)}",
+        ) from exc
+    return UpdateActionResponse(started=True, message="Rollback started")
+
+
+@app.get("/update/logs", dependencies=[Depends(get_current_admin)])
+def update_logs(settings: Settings = Depends(get_settings), limit: int = 200) -> list[dict]:
+    try:
+        return update.get_logs(settings, limit)
+    except Exception as exc:
+        logger.exception("Failed to retrieve update logs")
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"Failed to retrieve logs: {str(exc)}",
+        ) from exc
+
+
 @app.get("/", response_class=HTMLResponse)
 def index(request: Request) -> HTMLResponse:
     return templates.TemplateResponse("index.html", {"request": request})
diff --git a/backend/models.py b/backend/models.py
index b290194..d6f83ca 100644
--- a/backend/models.py
+++ b/backend/models.py
@@ -34,3 +34,32 @@ class LoginRequest(BaseModel):
 class LoginResponse(BaseModel):
     token: str
     expires_in: int
+
+
+class UpdateStatus(BaseModel):
+    current_version: str
+    last_status: str
+    last_error: Optional[str] = None
+    last_timestamp: Optional[str] = None
+
+
+class UpdateCheckResponse(BaseModel):
+    available: bool
+    latest_version: str
+    artifact_url: str
+    sha256: str
+    message: Optional[str] = None
+
+
+class UpdateActionResponse(BaseModel):
+    started: bool
+    message: str
+
+
+class UpdateLogEntry(BaseModel):
+    timestamp: str
+    status: str
+    message: Optional[str] = None
+    version: Optional[str] = None
+    error: Optional[str] = None
+    device_id: Optional[str] = None
diff --git a/backend/settings.py b/backend/settings.py
index e4b1165..8d7663a 100644
--- a/backend/settings.py
+++ b/backend/settings.py
@@ -39,6 +39,18 @@ class Settings:
         self.default_sound: bool = os.getenv("SKD_DEFAULT_SOUND", "false").lower() == "true"
         self.notify_timeout: int = int(os.getenv("SKD_NOTIFY_TIMEOUT", "5"))
         self.dry_run: bool = os.getenv("SKD_DRY_RUN", "false").lower() == "true"
+        self.update_url: str = os.getenv("SKD_UPDATE_URL", "https://update.wlkns.org")
+        self.update_token: str = os.getenv("SKD_UPDATE_TOKEN", "")
+        self.update_interval: int = int(os.getenv("SKD_UPDATE_INTERVAL", "3600"))
+        self.update_status_url: str = os.getenv(
+            "SKD_UPDATE_STATUS_URL", "https://update.wlkns.org/status"
+        )
+        self.update_status_file: str = os.getenv(
+            "SKD_UPDATE_STATUS_FILE", "/var/lib/skd/update_status.json"
+        )
+        self.update_log_file: str = os.getenv(
+            "SKD_UPDATE_LOG_FILE", "/var/lib/skd/update_logs.jsonl"
+        )
         # Paths/tools
         self.notify_send_path: str = os.getenv("SKD_NOTIFY_SEND_PATH", "notify-send")
         self.sound_player: str = os.getenv("SKD_SOUND_PLAYER", "paplay")
diff --git a/backend/templates/index.html b/backend/templates/index.html
index d355c44..1bd3bdd 100644
--- a/backend/templates/index.html
+++ b/backend/templates/index.html
@@ -84,6 +84,27 @@
     <div id="result" class="log"></div>
   </section>
 
+  <section>
+    <h3>Update-Verwaltung</h3>
+    <div id="updateStatus" class="log" style="margin-bottom: 1rem; padding: 1rem; background: var(--pico-card-background-color); border-radius: var(--pico-border-radius);">
+      Lade Update-Status...
+    </div>
+
+    <div class="grid">
+      <button id="checkUpdateBtn" type="button">Nach Updates suchen</button>
+      <button id="applyUpdateBtn" type="button" disabled>Update installieren</button>
+      <button id="rollbackBtn" type="button">Rollback durchführen</button>
+    </div>
+
+    <div id="updateResult" class="log" style="margin-top: 1rem;"></div>
+
+    <details style="margin-top: 1.5rem;">
+      <summary>Update-Logs anzeigen</summary>
+      <button id="refreshLogsBtn" type="button" style="margin-top: 0.5rem;">Logs neu laden</button>
+      <div id="updateLogs" class="log" style="margin-top: 1rem; max-height: 400px; overflow-y: auto;"></div>
+    </details>
+  </section>
+
     <script>
     const statusDiv = document.getElementById('status');
     const resultDiv = document.getElementById('result');
@@ -221,6 +242,169 @@
 
     checkSession();
     checkOidcStatus();
+
+    // ==================== Update Management ====================
+    const updateStatusDiv = document.getElementById('updateStatus');
+    const updateResultDiv = document.getElementById('updateResult');
+    const updateLogsDiv = document.getElementById('updateLogs');
+    const checkUpdateBtn = document.getElementById('checkUpdateBtn');
+    const applyUpdateBtn = document.getElementById('applyUpdateBtn');
+    const rollbackBtn = document.getElementById('rollbackBtn');
+    const refreshLogsBtn = document.getElementById('refreshLogsBtn');
+
+    let latestUpdateCheck = null;
+
+    async function refreshUpdateStatus() {
+      try {
+        const data = await api('/update/status');
+        const statusText = `
+Version: ${data.current_version}
+Letzter Status: ${data.last_status || 'unbekannt'}
+${data.last_error ? `Fehler: ${data.last_error}` : ''}
+${data.last_timestamp ? `Zeitstempel: ${new Date(data.last_timestamp).toLocaleString('de-DE')}` : ''}
+        `.trim();
+        updateStatusDiv.textContent = statusText;
+      } catch (err) {
+        updateStatusDiv.textContent = `Fehler beim Laden des Update-Status: ${err.message}`;
+      }
+    }
+
+    checkUpdateBtn.addEventListener('click', async () => {
+      updateResultDiv.textContent = 'Prüfe auf Updates...';
+      checkUpdateBtn.disabled = true;
+      try {
+        const data = await api('/update/check', { method: 'POST' });
+        latestUpdateCheck = data;
+
+        if (data.available) {
+          updateResultDiv.textContent = `
+✅ Update verfügbar!
+Version: ${data.latest_version}
+${data.message ? `Info: ${data.message}` : ''}
+
+Klicke auf "Update installieren" um fortzufahren.
+          `.trim();
+          applyUpdateBtn.disabled = false;
+        } else {
+          updateResultDiv.textContent = `✓ Keine Updates verfügbar. Aktuelle Version ist aktuell.`;
+          applyUpdateBtn.disabled = true;
+        }
+      } catch (err) {
+        updateResultDiv.textContent = `❌ Fehler beim Update-Check: ${err.message}`;
+        applyUpdateBtn.disabled = true;
+      } finally {
+        checkUpdateBtn.disabled = false;
+      }
+    });
+
+    applyUpdateBtn.addEventListener('click', async () => {
+      if (!latestUpdateCheck || !latestUpdateCheck.available) {
+        updateResultDiv.textContent = '❌ Bitte zuerst nach Updates suchen.';
+        return;
+      }
+
+      const confirmed = confirm(
+        `Update auf Version ${latestUpdateCheck.latest_version} installieren?\n\n` +
+        `⚠️ WICHTIG:\n` +
+        `- Ein Backup wird automatisch erstellt\n` +
+        `- Der Service wird neu gestartet\n` +
+        `- Bei Fehlern erfolgt automatischer Rollback\n\n` +
+        `Fortfahren?`
+      );
+
+      if (!confirmed) return;
+
+      updateResultDiv.textContent = 'Update wird gestartet... (läuft im Hintergrund)';
+      applyUpdateBtn.disabled = true;
+
+      try {
+        const data = await api('/update/apply', {
+          method: 'POST',
+          body: JSON.stringify({ version: latestUpdateCheck.latest_version })
+        });
+        updateResultDiv.textContent = `
+✓ ${data.message}
+
+Das Update läuft jetzt im Hintergrund.
+Aktualisiere den Status in wenigen Sekunden, um den Fortschritt zu sehen.
+        `.trim();
+
+        // Auto-refresh nach 5 Sekunden
+        setTimeout(() => {
+          refreshUpdateStatus();
+          applyUpdateBtn.disabled = true;
+        }, 5000);
+
+      } catch (err) {
+        updateResultDiv.textContent = `❌ Fehler beim Starten des Updates: ${err.message}`;
+        applyUpdateBtn.disabled = false;
+      }
+    });
+
+    rollbackBtn.addEventListener('click', async () => {
+      const confirmed = confirm(
+        `Rollback zum letzten Backup durchführen?\n\n` +
+        `⚠️ WICHTIG:\n` +
+        `- Dies stellt die vorherige Version wieder her\n` +
+        `- Der Service wird neu gestartet\n` +
+        `- Ein Backup muss vorhanden sein\n\n` +
+        `Fortfahren?`
+      );
+
+      if (!confirmed) return;
+
+      updateResultDiv.textContent = 'Rollback wird gestartet... (läuft im Hintergrund)';
+      rollbackBtn.disabled = true;
+
+      try {
+        const data = await api('/update/rollback', { method: 'POST' });
+        updateResultDiv.textContent = `
+✓ ${data.message}
+
+Der Rollback läuft jetzt im Hintergrund.
+Aktualisiere den Status in wenigen Sekunden.
+        `.trim();
+
+        // Auto-refresh nach 5 Sekunden
+        setTimeout(() => {
+          refreshUpdateStatus();
+        }, 5000);
+
+      } catch (err) {
+        updateResultDiv.textContent = `❌ Fehler beim Rollback: ${err.message}`;
+      } finally {
+        rollbackBtn.disabled = false;
+      }
+    });
+
+    async function refreshUpdateLogs() {
+      updateLogsDiv.textContent = 'Lade Logs...';
+      try {
+        const logs = await api('/update/logs');
+        if (!logs || logs.length === 0) {
+          updateLogsDiv.textContent = 'Keine Logs vorhanden.';
+          return;
+        }
+
+        // Reverse chronological (newest first)
+        const logEntries = logs.reverse().map(entry => {
+          const timestamp = entry.timestamp ? new Date(entry.timestamp).toLocaleString('de-DE') : 'unbekannt';
+          const status = entry.status || 'unknown';
+          const version = entry.version || '-';
+          const error = entry.error ? `\n  Fehler: ${entry.error}` : '';
+          return `[${timestamp}] ${status} - Version: ${version}${error}`;
+        });
+
+        updateLogsDiv.textContent = logEntries.join('\n\n');
+      } catch (err) {
+        updateLogsDiv.textContent = `Fehler beim Laden der Logs: ${err.message}`;
+      }
+    }
+
+    refreshLogsBtn.addEventListener('click', refreshUpdateLogs);
+
+    // Initial load
+    refreshUpdateStatus();
   </script>
 </body>
 </html>
diff --git a/backend/update.py b/backend/update.py
new file mode 100644
index 0000000..8629dc5
--- /dev/null
+++ b/backend/update.py
@@ -0,0 +1,142 @@
+import json
+import os
+import subprocess
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, List
+
+import httpx
+
+from backend.settings import Settings
+
+
+def _project_root() -> Path:
+    return Path(__file__).resolve().parents[1]
+
+
+def _read_version() -> str:
+    try:
+        return (_project_root() / "VERSION").read_text(encoding="utf-8").strip()
+    except OSError:
+        return "unknown"
+
+
+def _status_path(settings: Settings) -> Path:
+    return Path(settings.update_status_file)
+
+
+def _log_path(settings: Settings) -> Path:
+    return Path(settings.update_log_file)
+
+
+def _ensure_parent(path: Path) -> None:
+    path.parent.mkdir(parents=True, exist_ok=True)
+
+
+def _write_status(settings: Settings, status: str, version: str, error: str | None = None) -> None:
+    status_path = _status_path(settings)
+    _ensure_parent(status_path)
+    payload = {
+        "device_id": os.uname().nodename,
+        "version": version,
+        "status": status,
+        "error": error or "",
+        "timestamp": datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ"),
+    }
+    status_path.write_text(json.dumps(payload), encoding="utf-8")
+    _append_log(settings, payload)
+
+
+def _append_log(settings: Settings, payload: Dict[str, Any]) -> None:
+    log_path = _log_path(settings)
+    _ensure_parent(log_path)
+    with log_path.open("a", encoding="utf-8") as handle:
+        handle.write(json.dumps(payload) + "\n")
+
+
+def get_status(settings: Settings) -> Dict[str, Any]:
+    current_version = _read_version()
+    status_path = _status_path(settings)
+    if status_path.exists():
+        try:
+            data = json.loads(status_path.read_text(encoding="utf-8"))
+        except json.JSONDecodeError:
+            data = {}
+    else:
+        data = {}
+
+    return {
+        "current_version": current_version,
+        "last_status": data.get("status", "unknown"),
+        "last_error": data.get("error") or None,
+        "last_timestamp": data.get("timestamp"),
+    }
+
+
+def _parse_version(value: str) -> List[int]:
+    return [int(part) for part in value.split(".")]
+
+
+def check_update(settings: Settings) -> Dict[str, Any]:
+    headers = {}
+    if settings.update_token:
+        headers["Authorization"] = f"Bearer {settings.update_token}"
+
+    with httpx.Client(timeout=10.0) as client:
+        response = client.get(settings.update_url, headers=headers)
+        response.raise_for_status()
+        manifest = response.json()
+
+    latest_version = manifest.get("version", "")
+    artifact_url = manifest.get("artifact_url", "")
+    sha256 = manifest.get("sha256", "")
+    message = manifest.get("message")
+
+    available = False
+    current_version = _read_version()
+    try:
+        available = _parse_version(latest_version) > _parse_version(current_version)
+    except ValueError:
+        if latest_version and latest_version != current_version:
+            available = True
+
+    return {
+        "available": available,
+        "latest_version": latest_version,
+        "artifact_url": artifact_url,
+        "sha256": sha256,
+        "message": message,
+    }
+
+
+def _run_async(script_path: Path, settings: Settings) -> None:
+    env = os.environ.copy()
+    env["SKD_UPDATE_STATUS_FILE"] = settings.update_status_file
+    env["SKD_UPDATE_LOG_FILE"] = settings.update_log_file
+    subprocess.Popen([str(script_path)], env=env, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+
+
+def start_update(settings: Settings, version: str | None = None) -> None:
+    _write_status(settings, "in_progress", version or _read_version())
+    script = _project_root() / "scripts" / "update_client.sh"
+    _run_async(script, settings)
+
+
+def start_rollback(settings: Settings) -> None:
+    _write_status(settings, "in_progress", _read_version())
+    script = _project_root() / "scripts" / "rollback_client.sh"
+    _run_async(script, settings)
+
+
+def get_logs(settings: Settings, limit: int = 200) -> List[Dict[str, Any]]:
+    log_path = _log_path(settings)
+    if not log_path.exists():
+        return []
+    lines = log_path.read_text(encoding="utf-8").splitlines()
+    entries: List[Dict[str, Any]] = []
+    for line in lines[-limit:]:
+        try:
+            entries.append(json.loads(line))
+        except json.JSONDecodeError:
+            continue
+    return entries
diff --git a/docs/update-api.md b/docs/update-api.md
new file mode 100644
index 0000000..5a7b6fd
--- /dev/null
+++ b/docs/update-api.md
@@ -0,0 +1,60 @@
+ID: DOC_000006 | Version: 0.1.0 | Status: Draft
+By: Codex (GPT-5)
+
+# Update API (Kiddo Backend)
+
+## Purpose
+Definiert interne API-Endpunkte fuer Update-Status, Check, Apply, Rollback und Logs.
+
+## Endpoints
+
+### GET /update/status
+Antwort:
+```json
+{
+  "current_version": "0.1.2",
+  "last_status": "success|failed|unknown",
+  "last_error": "<optional>",
+  "last_timestamp": "2025-12-28T12:34:56Z"
+}
+```
+
+### POST /update/check
+Antwort:
+```json
+{
+  "available": true,
+  "latest_version": "0.1.3",
+  "artifact_url": "https://update.wlkns.org/kiddo/kiddo-0.1.3.tar.gz",
+  "sha256": "<hex>",
+  "message": "<optional>"
+}
+```
+
+### POST /update/apply
+Body (optional):
+```json
+{ "version": "0.1.3" }
+```
+Antwort:
+```json
+{ "started": true, "message": "update started" }
+```
+
+### POST /update/rollback
+Antwort:
+```json
+{ "started": true, "message": "rollback started" }
+```
+
+### GET /update/logs
+Antwort:
+```json
+[
+  {"timestamp":"2025-12-28T12:34:56Z","status":"success","message":"updated to 0.1.2"}
+]
+```
+
+## Notes
+- Alle Endpunkte erfordern Auth (Session/Bearer).
+- Apply/Rollback starten async; UI pollt /update/status.
diff --git a/docs/update-client.md b/docs/update-client.md
new file mode 100644
index 0000000..adc1ada
--- /dev/null
+++ b/docs/update-client.md
@@ -0,0 +1,49 @@
+ID: DOC_000004 | Version: 0.1.0 | Status: Draft
+By: Codex (GPT-5)
+
+# Client Update Flow (Kiddo)
+
+## Purpose
+Definiert den Client-seitigen Ablauf fuer das Pull-Update vom Update-Service.
+
+## Manifest Format (JSON)
+Beispiel:
+```json
+{
+  "version": "0.1.2",
+  "artifact_url": "https://update.wlkns.org/kiddo/kiddo-0.1.2.tar.gz",
+  "sha256": "<hex>",
+  "sig_url": "https://update.wlkns.org/kiddo/kiddo-0.1.2.sig"
+}
+```
+
+## Flow (High Level)
+1. Manifest abrufen (auth optional via Bearer Token).
+2. `artifact_url` herunterladen.
+3. SHA256 pruefen (Signatur optional).
+4. In Staging-Verzeichnis entpacken.
+5. Service stoppen.
+6. Atomic swap: aktuelles Verzeichnis sichern, Staging nach `/opt/sk` verschieben.
+7. Service starten.
+8. Bei Fehlern Rollback auf Backup.
+
+## Prototype Script
+- `scripts/update_client.sh` implementiert den Flow als CLI-Prototyp.
+- Erfordert `curl`, `tar`, `sha256sum`, `python3` und `systemctl`.
+
+## Rollback
+- Wenn Start fehlschlaegt: Backup nach `/opt/sk` zurueck, Service neu starten.
+- Backup-Verzeichnis benoetigt genuegend Speicher.
+
+## Security Notes
+- Artefakte muessen checksum-verifiziert sein.
+- Token-Handling ueber `SKD_UPDATE_TOKEN`.
+
+## Constraints
+- Update-Service ist extern (update.wlkns.org).
+- Service muss als root stoppen/starten koennen.
+
+## Status Reporting
+- Status wird per HTTP POST an `https://update.wlkns.org/status` gemeldet.
+- Schema siehe `docs/update-status.md`.
+- Lokaler Status/Logs liegen unter `/var/lib/skd` (konfigurierbar via ENV).
diff --git a/docs/update-status.md b/docs/update-status.md
new file mode 100644
index 0000000..a83af27
--- /dev/null
+++ b/docs/update-status.md
@@ -0,0 +1,25 @@
+ID: DOC_000005 | Version: 0.1.0 | Status: Draft
+By: Codex (GPT-5)
+
+# Update Status Reporting
+
+## Purpose
+Definiert das Status-Schema fuer Update-Resultate und den Uebertragungsweg.
+
+## Status Schema (JSON)
+```json
+{
+  "device_id": "<hostname>",
+  "version": "0.1.2",
+  "status": "success|failed",
+  "error": "<optional message>",
+  "timestamp": "2025-12-28T12:34:56Z"
+}
+```
+
+## Transport
+- HTTP POST an `https://update.wlkns.org/status`
+- Auth: Bearer Token (`SKD_UPDATE_TOKEN`)
+
+## Notes
+- Statusmeldungen sind best-effort; Fehler beim Senden blockieren kein Update.
diff --git a/env.example b/env.example
index 41120b9..5aae8f8 100644
--- a/env.example
+++ b/env.example
@@ -21,5 +21,12 @@ SKD_OIDC_STATE_COOKIE_NAME=skd_oidc_state
 SKD_DEFAULT_COUNTDOWN=60
 SKD_DEFAULT_SOUND=false
 SKD_NOTIFY_TIMEOUT=5
+# Update client configuration
+SKD_UPDATE_URL=https://update.wlkns.org
+SKD_UPDATE_TOKEN=
+SKD_UPDATE_INTERVAL=3600
+SKD_UPDATE_STATUS_URL=https://update.wlkns.org/status
+SKD_UPDATE_STATUS_FILE=/var/lib/skd/update_status.json
+SKD_UPDATE_LOG_FILE=/var/lib/skd/update_logs.jsonl
 # Set to true to test without performing real system changes
 SKD_DRY_RUN=false
diff --git a/project-management/PROJECT_STATUS.md b/project-management/PROJECT_STATUS.md
index 6371fc8..0d88290 100644
--- a/project-management/PROJECT_STATUS.md
+++ b/project-management/PROJECT_STATUS.md
@@ -10,9 +10,9 @@ Sicheres, remote steuerbares System zum Sperren/Entsperren lokaler Nutzerkonten.
 ✅ Stabilization
 
 ## Aktueller Fokus
-1. Dokumentierter Ist-Zustand der Module.
-2. Pflege der Anforderungen bei neuen Features.
-3. Doku und Ops-Automation aktuell halten.
+1. Client-Update-Mechanik planen (EPIC_000008).
+2. Dokumentierter Ist-Zustand der Module.
+3. Pflege der Anforderungen bei neuen Features.
 
 ## Projekt-Tagebuch (Kurz, optional)
 | Datum | Typ | Beschreibung |
@@ -86,12 +86,22 @@ Sicheres, remote steuerbares System zum Sperren/Entsperren lokaler Nutzerkonten.
 - [x] TASK_000023: README runbook notes
 
 ### EPIC_000008: Client-Side Update Mechanism
-- [ ] US_000026: Client bezieht Updates (Pull)
-- [ ] TASK_000027: Update endpoint config
-- [ ] US_000027: Client verifiziert und wendet Updates an
-- [ ] TASK_000028: Verify and apply update
-- [ ] US_000028: Client meldet Update-Status
-- [ ] TASK_000029: Report update status
+- [x] US_000026: Client bezieht Updates (Pull)
+- [x] TASK_000027: Update endpoint config
+- [x] US_000027: Client verifiziert und wendet Updates an
+- [x] TASK_000028: Verify and apply update
+- [x] US_000028: Client meldet Update-Status
+- [x] TASK_000029: Report update status
+- [x] US_000029: Update-Status im Web-UI anzeigen
+- [x] TASK_000030: UI update status view
+- [x] US_000030: Update-Check im Web-UI ausloesen
+- [x] TASK_000031: UI update check trigger
+- [x] US_000031: Update im Web-UI anstossen
+- [x] TASK_000032: UI update apply action
+- [x] US_000032: Update-Logs im Web-UI anzeigen
+- [x] TASK_000033: UI update logs view
+- [x] US_000033: Rollback im Web-UI anstossen
+- [x] TASK_000034: UI rollback action
 
 ### EPIC_000009: Update Webservice (External Team)
 - [ ] US_000026: Client bezieht Updates (Pull)
diff --git a/project-management/requirements/epics/EPIC_000008.md b/project-management/requirements/epics/EPIC_000008.md
index 39aeb13..e0bd41c 100644
--- a/project-management/requirements/epics/EPIC_000008.md
+++ b/project-management/requirements/epics/EPIC_000008.md
@@ -39,3 +39,8 @@ Ermoegliche einen robusten Client-Update-Flow mit Verifikation und Rollback.
 - US_000026: Client bezieht Updates (Pull)
 - US_000027: Client verifiziert und wendet Updates an
 - US_000028: Client meldet Update-Status
+- US_000029: Update-Status im Web-UI anzeigen
+- US_000030: Update-Check im Web-UI ausloesen
+- US_000031: Update im Web-UI anstossen
+- US_000032: Update-Logs im Web-UI anzeigen
+- US_000033: Rollback im Web-UI anstossen
diff --git a/project-management/requirements/stories/US_000026.md b/project-management/requirements/stories/US_000026.md
index 4472a65..08c02cc 100644
--- a/project-management/requirements/stories/US_000026.md
+++ b/project-management/requirements/stories/US_000026.md
@@ -1,9 +1,9 @@
-ID: US_000026 | Version: 0.1.0 | Status: Draft
+ID: US_000026 | Version: 0.1.0 | Status: Done
 By: Codex (GPT-5)
 
 # US_000026: Client bezieht Updates (Pull)
 
-Status: Draft
+Status: Done
 
 Als Betreiber moechte ich, dass der Client Updates per Pull von einem Update-Service bezieht, damit Deployments ohne SSH moeglich sind.
 
diff --git a/project-management/requirements/stories/US_000027.md b/project-management/requirements/stories/US_000027.md
index afc6b89..7a8a24d 100644
--- a/project-management/requirements/stories/US_000027.md
+++ b/project-management/requirements/stories/US_000027.md
@@ -1,9 +1,9 @@
-ID: US_000027 | Version: 0.1.0 | Status: Draft
+ID: US_000027 | Version: 0.1.0 | Status: Done
 By: Codex (GPT-5)
 
 # US_000027: Client verifiziert und wendet Updates an
 
-Status: Draft
+Status: Done
 
 Als Betreiber moechte ich, dass der Client Updates verifiziert und sicher anwendet, damit fehlerhafte Pakete keine Ausfaelle verursachen.
 
diff --git a/project-management/requirements/stories/US_000028.md b/project-management/requirements/stories/US_000028.md
index 27848c0..9a3e182 100644
--- a/project-management/requirements/stories/US_000028.md
+++ b/project-management/requirements/stories/US_000028.md
@@ -1,9 +1,9 @@
-ID: US_000028 | Version: 0.1.0 | Status: Draft
+ID: US_000028 | Version: 0.1.0 | Status: Done
 By: Codex (GPT-5)
 
 # US_000028: Client meldet Update-Status
 
-Status: Draft
+Status: Done
 
 Als Betreiber moechte ich Statusmeldungen vom Client erhalten, damit Update-Ergebnisse nachvollziehbar sind.
 
diff --git a/project-management/requirements/stories/US_000029.md b/project-management/requirements/stories/US_000029.md
new file mode 100644
index 0000000..82b2e78
--- /dev/null
+++ b/project-management/requirements/stories/US_000029.md
@@ -0,0 +1,17 @@
+ID: US_000029 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# US_000029: Update-Status im Web-UI anzeigen
+
+Status: Done
+
+Als Admin moechte ich die aktuelle Version und den Update-Status im Web-UI sehen, damit ich den Zustand schnell pruefen kann.
+
+## Akzeptanzkriterien
+- Given die Web-UI ist erreichbar
+- When ich den Update-Bereich aufrufe
+- Then ich sehe die aktuell laufende Version
+- And ich sehe den letzten Update-Status (success/failed) mit Zeitstempel
+
+## Task-Platzhalter
+- TASK_000030: UI update status view (Details bei Story-Start)
diff --git a/project-management/requirements/stories/US_000030.md b/project-management/requirements/stories/US_000030.md
new file mode 100644
index 0000000..afce1e0
--- /dev/null
+++ b/project-management/requirements/stories/US_000030.md
@@ -0,0 +1,17 @@
+ID: US_000030 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# US_000030: Update-Check im Web-UI ausloesen
+
+Status: Done
+
+Als Admin moechte ich manuell nach Updates suchen koennen, damit ich Updates sofort pruefen kann.
+
+## Akzeptanzkriterien
+- Given die Web-UI ist erreichbar
+- When ich auf "Nach Updates suchen" klicke
+- Then wird ein Check gegen `https://update.wlkns.org` gestartet
+- And das Ergebnis (neue Version verfuegbar/keine Updates/Fehler) wird angezeigt
+
+## Task-Platzhalter
+- TASK_000031: UI update check trigger (Details bei Story-Start)
diff --git a/project-management/requirements/stories/US_000031.md b/project-management/requirements/stories/US_000031.md
new file mode 100644
index 0000000..19e3fee
--- /dev/null
+++ b/project-management/requirements/stories/US_000031.md
@@ -0,0 +1,19 @@
+ID: US_000031 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# US_000031: Update im Web-UI anstossen
+
+Status: Done
+
+Als Admin moechte ich ein Update im Web-UI anstossen, damit der Client die neue Version installiert.
+
+## Akzeptanzkriterien
+- Given ein Update ist verfuegbar
+- And eine vorherige Version ist gesichert oder wird vor dem Start gesichert
+- When ich "Update installieren" ausloese
+- Then wird der Update-Client gestartet
+- And der Fortschritt/Status wird im UI angezeigt
+- And Fehler werden klar im UI gemeldet
+
+## Task-Platzhalter
+- TASK_000032: UI update apply action (Details bei Story-Start)
diff --git a/project-management/requirements/stories/US_000032.md b/project-management/requirements/stories/US_000032.md
new file mode 100644
index 0000000..81cc7b2
--- /dev/null
+++ b/project-management/requirements/stories/US_000032.md
@@ -0,0 +1,17 @@
+ID: US_000032 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# US_000032: Update-Logs im Web-UI anzeigen
+
+Status: Done
+
+Als Admin moechte ich Update-Logs im Web-UI einsehen, damit Fehler nachvollziehbar sind.
+
+## Akzeptanzkriterien
+- Given ein Update-Versuch wurde ausgefuehrt
+- When ich die Update-Logs oeffne
+- Then sehe ich eine chronologische Liste mit Zeitstempel und Ergebnis
+- And sensible Daten (Tokens) werden nicht angezeigt
+
+## Task-Platzhalter
+- TASK_000033: UI update logs view (Details bei Story-Start)
diff --git a/project-management/requirements/stories/US_000033.md b/project-management/requirements/stories/US_000033.md
new file mode 100644
index 0000000..67540c1
--- /dev/null
+++ b/project-management/requirements/stories/US_000033.md
@@ -0,0 +1,19 @@
+ID: US_000033 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# US_000033: Rollback im Web-UI anstossen
+
+Status: Done
+
+Als Admin moechte ich einen Rollback im Web-UI anstossen, damit ich nach einem fehlerhaften Update schnell zur letzten Version zurueckkehre.
+
+## Akzeptanzkriterien
+- Given ein vorheriger Update-Stand ist verfuegbar und wurde gesichert
+- And der Rollback darf nur starten, wenn das Backup verfuegbar ist
+- When ich "Rollback" ausloese
+- Then wird der Rollback-Mechanismus gestartet
+- And der Status/Fortschritt wird im UI angezeigt
+- And Fehler werden klar im UI gemeldet
+
+## Task-Platzhalter
+- TASK_000034: UI rollback action (Details bei Story-Start)
diff --git a/project-management/requirements/tasks/TASK_000027.md b/project-management/requirements/tasks/TASK_000027.md
new file mode 100644
index 0000000..b400851
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000027.md
@@ -0,0 +1,20 @@
+ID: TASK_000027 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000027: Update endpoint config
+
+## Outcome
+Client kennt Update-Endpoint, Auth und Polling-Konfiguration.
+
+## Story-Bezug
+US_000026
+
+## Beschreibung
+- Konfigurationskeys definieren (`SKD_UPDATE_URL`, `SKD_UPDATE_TOKEN`, `SKD_UPDATE_INTERVAL`).
+- Default auf `https://update.wlkns.org` festlegen.
+- Lesen der Config in Settings/ENV beschreiben.
+
+## Definition of Done (DoD)
+- Konfigurations-Keys dokumentiert (`env.example`, README).
+- Default-URL ist festgelegt (`https://update.wlkns.org`).
+- Settings laden die Update-Konfiguration aus ENV.
diff --git a/project-management/requirements/tasks/TASK_000028.md b/project-management/requirements/tasks/TASK_000028.md
new file mode 100644
index 0000000..0cc4207
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000028.md
@@ -0,0 +1,23 @@
+ID: TASK_000028 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000028: Verify and apply update
+
+## Outcome
+Update-Artefakt wird verifiziert und atomar angewendet.
+
+## Story-Bezug
+US_000027
+
+## Beschreibung
+- JSON-Manifest lesen (Version, `artifact_url`, `sha256`, optional `sig_url`).
+- `tar.gz` herunterladen und SHA256 pruefen.
+- Update atomar anwenden (staging, swap, rollback).
+- Fehlerfall dokumentieren (Rollback, Status).
+- Ablauf dokumentiert in `docs/update-client.md`.
+
+## Definition of Done (DoD)
+- Verifikation (Checksum/Signatur) ist beschrieben.
+- Atomare Anwendung und Rollback-Strategie sind definiert.
+- Fehlerbilder sind erfasst.
+- Prototyp-Skript ist als Referenz vorhanden.
diff --git a/project-management/requirements/tasks/TASK_000029.md b/project-management/requirements/tasks/TASK_000029.md
new file mode 100644
index 0000000..0b1d02c
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000029.md
@@ -0,0 +1,21 @@
+ID: TASK_000029 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000029: Report update status
+
+## Outcome
+Client meldet Update-Status mit Version und Fehlerbild.
+
+## Story-Bezug
+US_000028
+
+## Beschreibung
+- Status-Schema definieren (Version, Ergebnis, Fehler, Zeitpunkt).
+- Transportweg festlegen (z.B. HTTP POST oder Log-Export).
+- Erfolg/Fehler konsistent dokumentieren.
+- Schema dokumentiert in `docs/update-status.md`.
+
+## Definition of Done (DoD)
+- Status-Schema dokumentiert.
+- Uebertragungspfad beschrieben.
+- Erfolg/Fehler werden eindeutig gemeldet.
diff --git a/project-management/requirements/tasks/TASK_000030.md b/project-management/requirements/tasks/TASK_000030.md
new file mode 100644
index 0000000..8d75e27
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000030.md
@@ -0,0 +1,19 @@
+ID: TASK_000030 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000030: UI update status view
+
+## Outcome
+Web-UI zeigt aktuelle Version und letzten Update-Status.
+
+## Story-Bezug
+US_000029
+
+## Beschreibung
+- Update-Status und Version im UI anzeigen.
+- Letzten Status mit Zeitstempel visualisieren.
+- API-Basis: `GET /update/status` (siehe `docs/update-api.md`).
+
+## Definition of Done (DoD)
+- UI zeigt Version + letzten Status.
+- Fehler/keine Daten werden sauber angezeigt.
diff --git a/project-management/requirements/tasks/TASK_000031.md b/project-management/requirements/tasks/TASK_000031.md
new file mode 100644
index 0000000..c60340e
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000031.md
@@ -0,0 +1,19 @@
+ID: TASK_000031 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000031: UI update check trigger
+
+## Outcome
+Web-UI kann einen Update-Check gegen `https://update.wlkns.org` ausloesen.
+
+## Story-Bezug
+US_000030
+
+## Beschreibung
+- Button/Action fuer "Nach Updates suchen".
+- Ergebnisanzeige (Update verfuegbar/keine Updates/Fehler).
+- API-Basis: `POST /update/check` (siehe `docs/update-api.md`).
+
+## Definition of Done (DoD)
+- UI zeigt Ergebnis des Update-Checks.
+- Fehler werden klar angezeigt.
diff --git a/project-management/requirements/tasks/TASK_000032.md b/project-management/requirements/tasks/TASK_000032.md
new file mode 100644
index 0000000..3f85017
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000032.md
@@ -0,0 +1,21 @@
+ID: TASK_000032 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000032: UI update apply action
+
+## Outcome
+Web-UI kann ein Update installieren.
+
+## Story-Bezug
+US_000031
+
+## Beschreibung
+- "Update installieren" Action.
+- Vor Start Backup-Pruefung/Backup-Erstellung erzwingen.
+- Fortschritt/Status im UI.
+- API-Basis: `POST /update/apply` (siehe `docs/update-api.md`).
+
+## Definition of Done (DoD)
+- Update startet nur mit vorhandenem Backup.
+- UI zeigt Fortschritt/Status.
+- Fehler sind sichtbar.
diff --git a/project-management/requirements/tasks/TASK_000033.md b/project-management/requirements/tasks/TASK_000033.md
new file mode 100644
index 0000000..c476874
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000033.md
@@ -0,0 +1,19 @@
+ID: TASK_000033 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000033: UI update logs view
+
+## Outcome
+Web-UI zeigt Update-Logs chronologisch.
+
+## Story-Bezug
+US_000032
+
+## Beschreibung
+- Logliste mit Zeitstempel und Ergebnis.
+- Keine sensiblen Daten anzeigen.
+- API-Basis: `GET /update/logs` (siehe `docs/update-api.md`).
+
+## Definition of Done (DoD)
+- Logs sind sichtbar und chronologisch sortiert.
+- Sensible Daten sind ausgefiltert.
diff --git a/project-management/requirements/tasks/TASK_000034.md b/project-management/requirements/tasks/TASK_000034.md
new file mode 100644
index 0000000..1848b52
--- /dev/null
+++ b/project-management/requirements/tasks/TASK_000034.md
@@ -0,0 +1,20 @@
+ID: TASK_000034 | Version: 0.1.0 | Status: Done
+By: Codex (GPT-5)
+
+# TASK_000034: UI rollback action
+
+## Outcome
+Web-UI kann einen Rollback ausloesen.
+
+## Story-Bezug
+US_000033
+
+## Beschreibung
+- "Rollback" Action.
+- Nur aktiv, wenn Backup vorhanden.
+- Fortschritt/Status im UI.
+- API-Basis: `POST /update/rollback` (siehe `docs/update-api.md`).
+
+## Definition of Done (DoD)
+- Rollback startet nur bei verfuegbarem Backup.
+- UI zeigt Status/Fehler.
diff --git a/scripts/rollback_client.sh b/scripts/rollback_client.sh
new file mode 100755
index 0000000..85026b2
--- /dev/null
+++ b/scripts/rollback_client.sh
@@ -0,0 +1,76 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SERVICE_NAME="${SERVICE_NAME:-skd}"
+INSTALL_DIR="${INSTALL_DIR:-/opt/sk}"
+STATUS_FILE="${SKD_UPDATE_STATUS_FILE:-/var/lib/skd/update_status.json}"
+LOG_FILE="${SKD_UPDATE_LOG_FILE:-/var/lib/skd/update_logs.jsonl}"
+
+log() {
+  echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*"
+}
+
+write_status() {
+  local status="$1"
+  local error="${2:-}"
+  local version="$3"
+  SKD_STATUS="${status}" SKD_ERROR="${error}" SKD_VERSION="${version}" \
+    SKD_STATUS_FILE="${STATUS_FILE}" SKD_LOG_FILE="${LOG_FILE}" python3 - <<'PY'
+import json
+import os
+from datetime import datetime, timezone
+from pathlib import Path
+
+status = os.environ["SKD_STATUS"]
+error = os.environ.get("SKD_ERROR", "")
+version = os.environ.get("SKD_VERSION", "unknown")
+status_file = Path(os.environ["SKD_STATUS_FILE"])
+log_file = Path(os.environ["SKD_LOG_FILE"])
+
+status_file.parent.mkdir(parents=True, exist_ok=True)
+log_file.parent.mkdir(parents=True, exist_ok=True)
+
+payload = {
+    "device_id": os.uname().nodename,
+    "version": version,
+    "status": status,
+    "error": error,
+    "timestamp": datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ"),
+}
+status_file.write_text(json.dumps(payload), encoding="utf-8")
+with log_file.open("a", encoding="utf-8") as handle:
+    handle.write(json.dumps(payload) + "\n")
+PY
+}
+
+LATEST_BACKUP="$(ls -dt /opt/sk_backup_* 2>/dev/null | head -1 || true)"
+if [[ -z "${LATEST_BACKUP}" ]]; then
+  log "No backup found; rollback aborted."
+  write_status "failed" "no backup found" "unknown"
+  exit 1
+fi
+
+VERSION="unknown"
+if [[ -f "${LATEST_BACKUP}/VERSION" ]]; then
+  VERSION="$(cat "${LATEST_BACKUP}/VERSION" | tr -d '\n')"
+fi
+
+log "Stopping service ${SERVICE_NAME}..."
+sudo systemctl stop "${SERVICE_NAME}.service"
+
+FAILED_DIR="${INSTALL_DIR}_failed_$(date +%s)"
+log "Swapping ${INSTALL_DIR} -> ${FAILED_DIR}..."
+if [[ -d "${INSTALL_DIR}" ]]; then
+  sudo mv "${INSTALL_DIR}" "${FAILED_DIR}"
+fi
+sudo mv "${LATEST_BACKUP}" "${INSTALL_DIR}"
+
+log "Starting service ${SERVICE_NAME}..."
+if sudo systemctl start "${SERVICE_NAME}.service"; then
+  log "Rollback completed."
+  write_status "success" "" "${VERSION}"
+else
+  log "Rollback failed."
+  write_status "failed" "service start failed" "${VERSION}"
+  exit 1
+fi
diff --git a/scripts/update_client.sh b/scripts/update_client.sh
new file mode 100755
index 0000000..d3b4782
--- /dev/null
+++ b/scripts/update_client.sh
@@ -0,0 +1,171 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SERVICE_NAME="${SERVICE_NAME:-skd}"
+UPDATE_URL="${SKD_UPDATE_URL:-https://update.wlkns.org}"
+UPDATE_TOKEN="${SKD_UPDATE_TOKEN:-}"
+STATUS_URL="${SKD_UPDATE_STATUS_URL:-https://update.wlkns.org/status}"
+STATUS_FILE="${SKD_UPDATE_STATUS_FILE:-/var/lib/skd/update_status.json}"
+LOG_FILE="${SKD_UPDATE_LOG_FILE:-/var/lib/skd/update_logs.jsonl}"
+INSTALL_DIR="${INSTALL_DIR:-/opt/sk}"
+STAGING_DIR=""
+MANIFEST_FILE=""
+ARTIFACT_FILE=""
+BACKUP_DIR=""
+
+log() {
+  echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*"
+}
+
+report_status() {
+  local status="$1"
+  local error="${2:-}"
+  local timestamp
+  timestamp="$(date -u '+%Y-%m-%dT%H:%M:%SZ')"
+  python3 - <<'PY'
+import json
+import os
+from datetime import datetime, timezone
+from pathlib import Path
+
+device_id = os.uname().nodename
+version = os.environ.get("SKD_VERSION", "unknown")
+status = os.environ.get("SKD_STATUS", "unknown")
+error = os.environ.get("SKD_ERROR", "")
+timestamp = os.environ.get("SKD_TIMESTAMP") or datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")
+status_file = Path(os.environ["SKD_STATUS_FILE"])
+log_file = Path(os.environ["SKD_LOG_FILE"])
+
+status_file.parent.mkdir(parents=True, exist_ok=True)
+log_file.parent.mkdir(parents=True, exist_ok=True)
+
+payload = {
+    "device_id": device_id,
+    "version": version,
+    "status": status,
+    "error": error,
+    "timestamp": timestamp,
+}
+
+status_file.write_text(json.dumps(payload), encoding="utf-8")
+with log_file.open("a", encoding="utf-8") as handle:
+    handle.write(json.dumps(payload) + "\n")
+PY
+  local payload
+  payload=$(cat <<JSON
+{"device_id":"$(hostname)","version":"${VERSION}","status":"${status}","error":"${error}","timestamp":"${timestamp}"}
+JSON
+)
+  if [[ -n "${UPDATE_TOKEN}" ]]; then
+    curl -sS -X POST -H "Authorization: Bearer ${UPDATE_TOKEN}" -H "Content-Type: application/json" \
+      -d "${payload}" "${STATUS_URL}" >/dev/null || true
+  else
+    curl -sS -X POST -H "Content-Type: application/json" -d "${payload}" "${STATUS_URL}" >/dev/null || true
+  fi
+}
+
+cleanup() {
+  if [[ -n "${STAGING_DIR}" && -d "${STAGING_DIR}" ]]; then
+    rm -rf "${STAGING_DIR}"
+  fi
+  if [[ -n "${MANIFEST_FILE}" && -f "${MANIFEST_FILE}" ]]; then
+    rm -f "${MANIFEST_FILE}"
+  fi
+  if [[ -n "${ARTIFACT_FILE}" && -f "${ARTIFACT_FILE}" ]]; then
+    rm -f "${ARTIFACT_FILE}"
+  fi
+}
+trap cleanup EXIT
+
+require_cmd() {
+  if ! command -v "$1" >/dev/null 2>&1; then
+    echo "Required command not found: $1" >&2
+    exit 1
+  fi
+}
+
+require_cmd curl
+require_cmd tar
+require_cmd sha256sum
+require_cmd python3
+
+log "Fetching update manifest from ${UPDATE_URL}..."
+MANIFEST_FILE="$(mktemp)"
+if [[ -n "${UPDATE_TOKEN}" ]]; then
+  curl -fsS -H "Authorization: Bearer ${UPDATE_TOKEN}" "${UPDATE_URL}" -o "${MANIFEST_FILE}"
+else
+  curl -fsS "${UPDATE_URL}" -o "${MANIFEST_FILE}"
+fi
+
+read_manifest() {
+  python3 - <<'PY' "${MANIFEST_FILE}"
+import json
+import sys
+path = sys.argv[1]
+with open(path, "r", encoding="utf-8") as fh:
+    data = json.load(fh)
+for key in ("version", "artifact_url", "sha256"):
+    if key not in data:
+        sys.exit(f"Manifest missing '{key}'")
+print(data["version"])
+print(data["artifact_url"])
+print(data["sha256"])
+PY
+}
+
+readarray -t manifest_values < <(read_manifest)
+VERSION="${manifest_values[0]}"
+ARTIFACT_URL="${manifest_values[1]}"
+ARTIFACT_SHA256="${manifest_values[2]}"
+
+log "Downloading artifact ${ARTIFACT_URL} (version ${VERSION})..."
+ARTIFACT_FILE="$(mktemp --suffix=.tar.gz)"
+if [[ -n "${UPDATE_TOKEN}" ]]; then
+  curl -fsS -H "Authorization: Bearer ${UPDATE_TOKEN}" "${ARTIFACT_URL}" -o "${ARTIFACT_FILE}"
+else
+  curl -fsS "${ARTIFACT_URL}" -o "${ARTIFACT_FILE}"
+fi
+
+log "Verifying checksum..."
+CALC_SHA="$(sha256sum "${ARTIFACT_FILE}" | awk '{print $1}')"
+if [[ "${CALC_SHA}" != "${ARTIFACT_SHA256}" ]]; then
+  echo "Checksum mismatch: expected ${ARTIFACT_SHA256} got ${CALC_SHA}" >&2
+  SKD_VERSION="${VERSION}" SKD_STATUS="failed" SKD_ERROR="checksum mismatch" \
+    SKD_TIMESTAMP="$(date -u '+%Y-%m-%dT%H:%M:%SZ')" SKD_STATUS_FILE="${STATUS_FILE}" \
+    SKD_LOG_FILE="${LOG_FILE}" report_status "failed" "checksum mismatch"
+  exit 1
+fi
+
+STAGING_DIR="$(mktemp -d /opt/sk_update.XXXXXX)"
+log "Extracting to staging ${STAGING_DIR}..."
+ tar -xzf "${ARTIFACT_FILE}" -C "${STAGING_DIR}"
+
+BACKUP_DIR="/opt/sk_backup_${VERSION}_$(date +%s)"
+log "Stopping service ${SERVICE_NAME}..."
+ sudo systemctl stop "${SERVICE_NAME}.service"
+
+log "Swapping ${INSTALL_DIR} -> ${BACKUP_DIR}..."
+if [[ -d "${INSTALL_DIR}" ]]; then
+  sudo mv "${INSTALL_DIR}" "${BACKUP_DIR}"
+fi
+sudo mv "${STAGING_DIR}" "${INSTALL_DIR}"
+STAGING_DIR=""
+
+log "Starting service ${SERVICE_NAME}..."
+if sudo systemctl start "${SERVICE_NAME}.service"; then
+  log "Update applied successfully."
+  SKD_VERSION="${VERSION}" SKD_STATUS="success" SKD_ERROR="" \
+    SKD_TIMESTAMP="$(date -u '+%Y-%m-%dT%H:%M:%SZ')" SKD_STATUS_FILE="${STATUS_FILE}" \
+    SKD_LOG_FILE="${LOG_FILE}" report_status "success" ""
+else
+  log "Service failed to start, rolling back..."
+  sudo rm -rf "${INSTALL_DIR}"
+  if [[ -d "${BACKUP_DIR}" ]]; then
+    sudo mv "${BACKUP_DIR}" "${INSTALL_DIR}"
+  fi
+  sudo systemctl start "${SERVICE_NAME}.service" || true
+  SKD_VERSION="${VERSION}" SKD_STATUS="failed" SKD_ERROR="service start failed" \
+    SKD_TIMESTAMP="$(date -u '+%Y-%m-%dT%H:%M:%SZ')" SKD_STATUS_FILE="${STATUS_FILE}" \
+    SKD_LOG_FILE="${LOG_FILE}" report_status "failed" "service start failed"
+  exit 1
+fi