diff --git a/src/PayBeat.App/App.xaml.cs b/src/PayBeat.App/App.xaml.cs
index c157fcb..bd88c06 100644
--- a/src/PayBeat.App/App.xaml.cs
+++ b/src/PayBeat.App/App.xaml.cs
@@ -58,68 +58,27 @@ protected override void OnStartup(StartupEventArgs e)
     {
         base.OnStartup(e);
 
-        _settingsService = new SettingsService();
-        var settings = _settingsService.Load();
-        _startupSettings = settings;
-        LocalizationService.Apply(settings.Language);
-        ThemeService.Apply(settings.Theme);
+        var settings = LoadStartupSettings();
 
-        _singleInstanceMutex = new Mutex(initiallyOwned: true, "PayBeat_SingleInstance", out var createdNew);
-        if (!createdNew)
+        if (!TryAcquireSingleInstance())
         {
-            MessageBox.Show(
-                (string)FindResource("Error.AlreadyRunning")!,
-                "PayBeat",
-                MessageBoxButton.OK,
-                MessageBoxImage.Information);
-            Shutdown();
             return;
         }
-        SystemEvents.SessionEnding += OnSessionEnding;
-        _mainVm = new MainViewModel(_settingsService);
-        _mainVm.HotkeySettingsChanged += OnHotkeySettingsChanged;
 
-        _mainWindow = new MainWindow { DataContext = _mainVm };
-        _mainWindow.SourceInitialized += (_, _) =>
-        {
-            var s = _settingsService.Load();
-            _hotkeyService = new HotkeyService();
-            var registered = _hotkeyService.Register(_mainWindow, s.HotkeyModifiers, s.HotkeyVirtualKey);
-            if (!registered)
-            {
-                var key = HotkeyService.Format(s.HotkeyModifiers, s.HotkeyVirtualKey);
-                MessageBox.Show(
-                    string.Format((string)FindResource("Error.HotkeyConflict")!, key),
-                    "PayBeat",
-                    MessageBoxButton.OK,
-                    MessageBoxImage.Warning);
-            }
-            _hotkeyService.Triggered += ToggleWindowVisibility;
-        };
-        _mainWindow.ContentRendered += OnMainWindowContentRendered;
+        SystemEvents.SessionEnding += OnSessionEnding;
+        CreateMainViewModelAndWindow();
 
         if (settings.DisplayMode == DisplayMode.None)
         {
-            // Only create the HWND (for hotkey registration) without showing the window.
-            new WindowInteropHelper(_mainWindow).EnsureHandle();
-            _mainWindow.ContentRendered -= OnMainWindowContentRendered;
-            _trayIconService = new TrayIconService(_mainVm, ActivateMainWindow);
-            return;
+            StartHiddenInTray();
         }
-
-        _mainWindow.IsRestoringStartupPosition = settings.DisplayMode is DisplayMode.Normal or DisplayMode.Mini or DisplayMode.Flex;
-        if (settings.DisplayMode is DisplayMode.Normal or DisplayMode.Mini)
+        else
         {
-            var startupPos = GetSavedPosition(settings, settings.DisplayMode);
-            if (startupPos != null)
-            {
-                _mainWindow.Left = startupPos.Left;
-                _mainWindow.Top = startupPos.Top;
-            }
+            ShowMainWindow(settings);
         }
 
-        _mainWindow.Show();
-        _trayIconService = new TrayIconService(_mainVm, ActivateMainWindow);
+        _trayIconService = new TrayIconService(_mainVm!, ActivateMainWindow);
+        CheckForUpdatesOnStartup(settings);
     }
 
     // Run restore after first render because clamping depends on measured window size.
@@ -144,14 +103,14 @@ private static void ApplyStartupPlacement(MainWindow mainWindow, SalarySettings
     }
 
     private static WindowPosition? GetSavedPosition(SalarySettings settings, DisplayMode mode) =>
-            mode switch
-            {
-                DisplayMode.Normal => settings.NormalPosition,
-                DisplayMode.Mini => settings.MiniPosition,
-                DisplayMode.None => null,
-                DisplayMode.Flex => null,
-                _ => null
-            };
+                mode switch
+                {
+                    DisplayMode.Normal => settings.NormalPosition,
+                    DisplayMode.Mini => settings.MiniPosition,
+                    DisplayMode.None => null,
+                    DisplayMode.Flex => null,
+                    _ => null
+                };
 
     /// <summary>
     /// Restore Flex by preferred monitor name, falling back to nearest available monitor.
@@ -201,6 +160,51 @@ private void ActivateMainWindow()
         _mainWindow.PlayAttentionAnimation();
     }
 
+    /// <summary>
+    /// Fires a best-effort, fire-and-forget update check, throttled to once per 24 hours via
+    /// <see cref="SalarySettings.LastUpdateCheckUtc"/>.
+    /// </summary>
+    private void CheckForUpdatesOnStartup(SalarySettings settings)
+    {
+        if (settings.LastUpdateCheckUtc is { } last && DateTimeOffset.UtcNow - last < TimeSpan.FromHours(24))
+        {
+            return;
+        }
+
+        _ = Task.Run(async () =>
+        {
+            var info = await new UpdateCheckService().GetLatestReleaseAsync();
+            _settingsService!.Save(_settingsService.Load() with
+            {
+                LastUpdateCheckUtc = DateTimeOffset.UtcNow
+            });
+            if (info != null)
+            {
+                Dispatcher.Invoke(() => _mainVm!.NotifyUpdateAvailable(info.Version));
+            }
+        });
+    }
+
+    private void CreateMainViewModelAndWindow()
+    {
+        _mainVm = new MainViewModel(_settingsService!);
+        _mainVm.HotkeySettingsChanged += OnHotkeySettingsChanged;
+
+        _mainWindow = new MainWindow { DataContext = _mainVm };
+        _mainWindow.SourceInitialized += OnMainWindowSourceInitialized;
+        _mainWindow.ContentRendered += OnMainWindowContentRendered;
+    }
+
+    private SalarySettings LoadStartupSettings()
+    {
+        _settingsService = new SettingsService();
+        var settings = _settingsService.Load();
+        _startupSettings = settings;
+        LocalizationService.Apply(settings.Language);
+        ThemeService.Apply(settings.Theme);
+        return settings;
+    }
+
     private void OnHotkeySettingsChanged()
     {
         var s = _settingsService!.Load();
@@ -231,6 +235,23 @@ private void OnMainWindowContentRendered(object? sender, EventArgs e)
         _mainWindow.IsRestoringStartupPosition = false;
     }
 
+    private void OnMainWindowSourceInitialized(object? sender, EventArgs e)
+    {
+        var s = _settingsService!.Load();
+        _hotkeyService = new HotkeyService();
+        var registered = _hotkeyService.Register(_mainWindow!, s.HotkeyModifiers, s.HotkeyVirtualKey);
+        if (!registered)
+        {
+            var key = HotkeyService.Format(s.HotkeyModifiers, s.HotkeyVirtualKey);
+            MessageBox.Show(
+                string.Format((string)FindResource("Error.HotkeyConflict")!, key),
+                "PayBeat",
+                MessageBoxButton.OK,
+                MessageBoxImage.Warning);
+        }
+        _hotkeyService.Triggered += ToggleWindowVisibility;
+    }
+
     /// <summary>
     /// Proactively saves the window position when Windows is shutting down or the user is logging off.
     /// WPF does not guarantee that <see cref="Window.Closing"/>/<see cref="OnExit"/> run in response to
@@ -267,6 +288,29 @@ private void SaveWindowPosition(WindowPosition pos)
         _settingsService.Save(updated);
     }
 
+    private void ShowMainWindow(SalarySettings settings)
+    {
+        _mainWindow!.IsRestoringStartupPosition = settings.DisplayMode is DisplayMode.Normal or DisplayMode.Mini or DisplayMode.Flex;
+        if (settings.DisplayMode is DisplayMode.Normal or DisplayMode.Mini)
+        {
+            var startupPos = GetSavedPosition(settings, settings.DisplayMode);
+            if (startupPos != null)
+            {
+                _mainWindow.Left = startupPos.Left;
+                _mainWindow.Top = startupPos.Top;
+            }
+        }
+
+        _mainWindow.Show();
+    }
+
+    // Only create the HWND (for hotkey registration) without showing the window.
+    private void StartHiddenInTray()
+    {
+        new WindowInteropHelper(_mainWindow!).EnsureHandle();
+        _mainWindow!.ContentRendered -= OnMainWindowContentRendered;
+    }
+
     private void ToggleWindowVisibility()
     {
         if (_windowsHidden)
@@ -295,4 +339,21 @@ private void ToggleWindowVisibility()
             _trayIconService?.SetHidden(true);
         }
     }
+
+    private bool TryAcquireSingleInstance()
+    {
+        _singleInstanceMutex = new Mutex(initiallyOwned: true, "PayBeat_SingleInstance", out var createdNew);
+        if (createdNew)
+        {
+            return true;
+        }
+
+        MessageBox.Show(
+            (string)FindResource("Error.AlreadyRunning")!,
+            "PayBeat",
+            MessageBoxButton.OK,
+            MessageBoxImage.Information);
+        Shutdown();
+        return false;
+    }
 }
\ No newline at end of file
diff --git a/src/PayBeat.App/Helpers/AppVersion.cs b/src/PayBeat.App/Helpers/AppVersion.cs
new file mode 100644
index 0000000..5cf5d5c
--- /dev/null
+++ b/src/PayBeat.App/Helpers/AppVersion.cs
@@ -0,0 +1,29 @@
+using System.Reflection;
+
+namespace PayBeat.App.Helpers;
+
+/// <summary>
+/// Resolves the running app's version from assembly metadata, stripping MinVer's
+/// build-metadata suffix (anything after '+').
+/// </summary>
+public static class AppVersion
+{
+    /// <summary>The current version string, e.g. <c>1.2.0</c>, or empty if unavailable.</summary>
+    public static string Current { get; } = Resolve();
+
+    private static string Resolve()
+    {
+        var version = Assembly.GetExecutingAssembly()
+            .GetCustomAttribute<AssemblyInformationalVersionAttribute>()
+            ?.InformationalVersion
+            ?? Assembly.GetExecutingAssembly().GetName().Version?.ToString(3);
+
+        if (version is null)
+        {
+            return string.Empty;
+        }
+
+        var plus = version.IndexOf('+');
+        return plus >= 0 ? version[..plus] : version;
+    }
+}
diff --git a/src/PayBeat.App/Models/SalarySettings.cs b/src/PayBeat.App/Models/SalarySettings.cs
index 1574432..4fe95cc 100644
--- a/src/PayBeat.App/Models/SalarySettings.cs
+++ b/src/PayBeat.App/Models/SalarySettings.cs
@@ -134,4 +134,12 @@ public WindowPosition? FlexPosition
     /// supported explicit values are <c>"light"</c> and <c>"dark"</c>.
     /// </summary>
     public string Theme { get; init; } = "auto";
+
+    /// <summary>
+    /// Last time an automatic startup update check ran, used to throttle checks to once per day.
+    /// </summary>
+    public DateTimeOffset? LastUpdateCheckUtc
+    {
+        get; init;
+    }
 }
\ No newline at end of file
diff --git a/src/PayBeat.App/Resources/Strings.en.xaml b/src/PayBeat.App/Resources/Strings.en.xaml
index 81106be..e96068f 100644
--- a/src/PayBeat.App/Resources/Strings.en.xaml
+++ b/src/PayBeat.App/Resources/Strings.en.xaml
@@ -79,6 +79,9 @@
     <sys:String x:Key="About.License">License</sys:String>
     <sys:String x:Key="About.GitHub">GitHub</sys:String>
     <sys:String x:Key="About.Close">Close</sys:String>
+    <sys:String x:Key="About.Update.Checking">Checking for updates...</sys:String>
+    <sys:String x:Key="About.Update.UpToDate">You're up to date</sys:String>
+    <sys:String x:Key="About.Update.Available">Update available: v{0}</sys:String>
 
     <!-- Validation errors -->
     <sys:String x:Key="Error.SalaryPositive">Daily salary must be greater than 0</sys:String>
@@ -97,5 +100,7 @@
     <sys:String x:Key="Notification.MilestoneBody">You've earned {0} today!</sys:String>
     <sys:String x:Key="Notification.EndOfDayTitle">Almost Done</sys:String>
     <sys:String x:Key="Notification.EndOfDayBody">Work ends in {0} minutes.</sys:String>
+    <sys:String x:Key="Notification.UpdateAvailableTitle">Update Available</sys:String>
+    <sys:String x:Key="Notification.UpdateAvailableBody">PayBeat v{0} is available. Open About to download it.</sys:String>
 
 </ResourceDictionary>
diff --git a/src/PayBeat.App/Resources/Strings.zh-CN.xaml b/src/PayBeat.App/Resources/Strings.zh-CN.xaml
index 52f9c9e..c4d6b68 100644
--- a/src/PayBeat.App/Resources/Strings.zh-CN.xaml
+++ b/src/PayBeat.App/Resources/Strings.zh-CN.xaml
@@ -79,6 +79,9 @@
     <sys:String x:Key="About.License">许可证</sys:String>
     <sys:String x:Key="About.GitHub">GitHub</sys:String>
     <sys:String x:Key="About.Close">关闭</sys:String>
+    <sys:String x:Key="About.Update.Checking">正在检查更新...</sys:String>
+    <sys:String x:Key="About.Update.UpToDate">已是最新版本</sys:String>
+    <sys:String x:Key="About.Update.Available">发现新版本：v{0}</sys:String>
 
     <!-- Validation errors -->
     <sys:String x:Key="Error.SalaryPositive">日薪须大于 0</sys:String>
@@ -97,5 +100,7 @@
     <sys:String x:Key="Notification.MilestoneBody">今天已赚到 {0}！</sys:String>
     <sys:String x:Key="Notification.EndOfDayTitle">快下班了</sys:String>
     <sys:String x:Key="Notification.EndOfDayBody">还有 {0} 分钟下班。</sys:String>
+    <sys:String x:Key="Notification.UpdateAvailableTitle">发现新版本</sys:String>
+    <sys:String x:Key="Notification.UpdateAvailableBody">PayBeat v{0} 已发布，打开"关于"窗口下载。</sys:String>
 
 </ResourceDictionary>
diff --git a/src/PayBeat.App/Services/UpdateCheckService.cs b/src/PayBeat.App/Services/UpdateCheckService.cs
new file mode 100644
index 0000000..73835b1
--- /dev/null
+++ b/src/PayBeat.App/Services/UpdateCheckService.cs
@@ -0,0 +1,68 @@
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Text.Json;
+using PayBeat.App.Helpers;
+
+namespace PayBeat.App.Services;
+
+/// <summary>Latest available release, as reported by the GitHub Releases API.</summary>
+public sealed record UpdateInfo(string Version, string HtmlUrl);
+
+/// <summary>
+/// Checks the project's GitHub Releases feed for a newer stable version than the running build.
+/// Best-effort only: any network, parsing, or version-comparison failure results in a null return.
+/// </summary>
+public sealed class UpdateCheckService
+{
+    private const string LatestReleaseUrl = "https://api.github.com/repos/coldhighsun/PayBeat/releases/latest";
+
+    private static readonly HttpClient HttpClient = CreateHttpClient();
+
+    /// <summary>
+    /// Returns the latest stable release if it is newer than <see cref="AppVersion.Current"/>,
+    /// or <c>null</c> if there is no newer release or the check failed.
+    /// </summary>
+    public async Task<UpdateInfo?> GetLatestReleaseAsync(CancellationToken cancellationToken = default)
+    {
+        try
+        {
+            using var response = await HttpClient.GetAsync(LatestReleaseUrl, cancellationToken);
+            if (!response.IsSuccessStatusCode)
+            {
+                return null;
+            }
+
+            using var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
+            using var json = await JsonDocument.ParseAsync(stream, cancellationToken: cancellationToken);
+
+            var tagName = json.RootElement.GetProperty("tag_name").GetString();
+            var htmlUrl = json.RootElement.GetProperty("html_url").GetString();
+            if (string.IsNullOrEmpty(tagName) || string.IsNullOrEmpty(htmlUrl))
+            {
+                return null;
+            }
+
+            var latestVersionText = tagName.StartsWith('v') ? tagName[1..] : tagName;
+            if (!Version.TryParse(latestVersionText, out var latestVersion)
+                || !Version.TryParse(AppVersion.Current, out var currentVersion)
+                || latestVersion <= currentVersion)
+            {
+                return null;
+            }
+
+            return new UpdateInfo(latestVersionText, htmlUrl);
+        }
+        catch (Exception ex) when (ex is HttpRequestException or JsonException or TaskCanceledException or KeyNotFoundException or InvalidOperationException)
+        {
+            return null;
+        }
+    }
+
+    private static HttpClient CreateHttpClient()
+    {
+        var client = new HttpClient { Timeout = TimeSpan.FromSeconds(10) };
+        client.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("PayBeat", AppVersion.Current));
+        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/vnd.github+json"));
+        return client;
+    }
+}
\ No newline at end of file
diff --git a/src/PayBeat.App/ViewModels/MainViewModel.cs b/src/PayBeat.App/ViewModels/MainViewModel.cs
index 7e3e393..863bf61 100644
--- a/src/PayBeat.App/ViewModels/MainViewModel.cs
+++ b/src/PayBeat.App/ViewModels/MainViewModel.cs
@@ -238,11 +238,17 @@ private void OpenAbout()
             }
         }
 
-        var win = new AboutWindow();
+        var win = new AboutWindow(_settingsService);
         ApplyTopmostIfNeeded(win);
         win.Show();
     }
 
+    /// <summary>Raises <see cref="NotificationRequested"/> with a localized "update available" message.</summary>
+    public void NotifyUpdateAvailable(string version) =>
+        NotificationRequested?.Invoke(
+            LocalizationService.Get("Notification.UpdateAvailableTitle"),
+            string.Format(LocalizationService.Get("Notification.UpdateAvailableBody"), version));
+
     private void OpenSettings()
     {
         foreach (Window w in Application.Current.Windows)
diff --git a/src/PayBeat.App/Views/AboutWindow.xaml b/src/PayBeat.App/Views/AboutWindow.xaml
index 3ced9a7..05e0fc8 100644
--- a/src/PayBeat.App/Views/AboutWindow.xaml
+++ b/src/PayBeat.App/Views/AboutWindow.xaml
@@ -74,6 +74,21 @@
                            FontSize="12"
                            HorizontalAlignment="Center"
                            Margin="0,4,0,0"/>
+                <TextBlock x:Name="UpdateStatusText"
+                           Foreground="{DynamicResource MutedBrush}"
+                           FontSize="11"
+                           HorizontalAlignment="Center"
+                           Margin="0,4,0,0"/>
+                <TextBlock x:Name="UpdateStatusLinkContainer"
+                           Visibility="Collapsed"
+                           FontSize="11"
+                           HorizontalAlignment="Center"
+                           Margin="0,4,0,0">
+                    <Hyperlink x:Name="UpdateStatusLink"
+                               Foreground="{DynamicResource BlueBrush}"
+                               TextDecorations="None"
+                               RequestNavigate="GitHubLink_RequestNavigate"/>
+                </TextBlock>
             </StackPanel>
 
             <!-- Description -->
diff --git a/src/PayBeat.App/Views/AboutWindow.xaml.cs b/src/PayBeat.App/Views/AboutWindow.xaml.cs
index 2bf8189..fb41ab2 100644
--- a/src/PayBeat.App/Views/AboutWindow.xaml.cs
+++ b/src/PayBeat.App/Views/AboutWindow.xaml.cs
@@ -1,42 +1,49 @@
+using PayBeat.App.Helpers;
+using PayBeat.App.Services;
 using System.Diagnostics;
-using System.Reflection;
 using System.Windows.Navigation;
 
 namespace PayBeat.App.Views;
 
 /// <summary>
-/// Displays app version, author, and license information.
+/// Displays app version, author, and license information, and checks for updates on open.
 /// </summary>
 public partial class AboutWindow
 {
+    private readonly SettingsService _settingsService;
+
     /// <summary>
-    /// Initializes the about window and populates the version label.
+    /// Initializes the about window, populates the version label, and starts an update check.
     /// </summary>
-    public AboutWindow()
+    public AboutWindow(SettingsService settingsService)
     {
+        _settingsService = settingsService;
         InitializeComponent();
-        VersionText.Text = GetVersionString();
+        VersionText.Text = $"v{AppVersion.Current}";
+        UpdateStatusText.Text = LocalizationService.Get("About.Update.Checking");
+        _ = CheckForUpdatesAsync();
     }
 
-    private static string GetVersionString()
+    private async Task CheckForUpdatesAsync()
     {
-        var version = Assembly.GetExecutingAssembly()
-            .GetCustomAttribute<AssemblyInformationalVersionAttribute>()
-            ?.InformationalVersion
-            ?? Assembly.GetExecutingAssembly().GetName().Version?.ToString(3);
+        var info = await new UpdateCheckService().GetLatestReleaseAsync();
+        _settingsService.Save(_settingsService.Load() with
+        {
+            LastUpdateCheckUtc = DateTimeOffset.UtcNow
+        });
 
-        if (version is null)
+        if (info != null)
         {
-            return string.Empty;
+            UpdateStatusText.Text = string.Empty;
+            UpdateStatusLink.NavigateUri = new Uri(info.HtmlUrl);
+            UpdateStatusLink.Inlines.Clear();
+            UpdateStatusLink.Inlines.Add(string.Format(LocalizationService.Get("About.Update.Available"), info.Version));
+            UpdateStatusLinkContainer.Visibility = Visibility.Visible;
         }
-
-        var plus = version.IndexOf('+');
-        if (plus >= 0)
+        else
         {
-            version = version[..plus];
+            UpdateStatusText.Text = LocalizationService.Get("About.Update.UpToDate");
         }
-
-        return $"v{version}";
     }
 
     private void CloseButton_Click(object sender, RoutedEventArgs e)