diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index 25de914..ebc68ad 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -190,6 +190,8 @@ git push
 - `Packages/XStatsKit/Sources/XStatsUI/Rest`：本机休息计时、幕布、Mini HUD 与合成声音。
 - `Packages/XStatsKit/Tests`：Swift 单元测试。
 
+更新提醒：通知设置中的“新版本更新”默认开启，沿用自动更新检查调度；后台发现未跳过的新版本时发送系统通知，不主动打开升级窗口。“运行时静默”与“从不”继续保持静默，手动检查仍显示更新窗口。仅在通知成功提交后记录最近提醒版本，跨重启去重；权限拒绝或发送失败不消耗提醒机会。点击通知打开更新窗口，重启后尚无清单时重新检查。通知偏好参与设置备份，提醒记录仅留在本机。
+
 菜单栏绘图：每个状态项仅保存上一轮绘图读数，相关数值未变化时复用图像；历史风格继续比较历史数据，设置、语言、外观与布局变化必须使缓存失效。悬停提示独立更新。设置页实时预览在主窗口关闭或最小化时停止观察采样数据，快照渲染不受影响。验证需包含后台 CPU 对照，以及风格、充电状态和历史曲线的刷新边界。
 
 硬件能力：风扇相关入口仅在成功读取到大于 0 的风扇数量后显示；尚未采样、数量未知或明确为 0 时隐藏。未知不等同于无风扇，仍沿既有需求采样重试；已确认的数量保留至本次运行结束，短暂读取失败与转速为 0 不导致入口消失。能力过滤不改写用户保存的展示偏好。
diff --git a/Packages/XStatsKit/Sources/Localization/Resources/ar.tsv b/Packages/XStatsKit/Sources/Localization/Resources/ar.tsv
index 99d1967..172ee43 100644
--- a/Packages/XStatsKit/Sources/Localization/Resources/ar.tsv
+++ b/Packages/XStatsKit/Sources/Localization/Resources/ar.tsv
@@ -1608,3 +1608,6 @@ Homebrew 将按执行时的状态清理旧版本与缓存，不自动移除依
 续	متابعة
 GitHub 项目	مشروع GitHub
 赞助 XStats	ادعم XStats
+新版本更新	تحديثات الإصدارات الجديدة
+后台发现新版本时通知，每个版本仅提醒一次	الإشعار عند العثور على تحديث في الخلفية، مرة واحدة لكل إصدار
+点击查看更新内容并安装。	انقر للاطلاع على المستجدات وتثبيت التحديث.
diff --git a/Packages/XStatsKit/Sources/Localization/Resources/de.tsv b/Packages/XStatsKit/Sources/Localization/Resources/de.tsv
index e1f8438..d2e0413 100644
--- a/Packages/XStatsKit/Sources/Localization/Resources/de.tsv
+++ b/Packages/XStatsKit/Sources/Localization/Resources/de.tsv
@@ -1608,3 +1608,6 @@ Homebrew 将按执行时的状态清理旧版本与缓存，不自动移除依
 续	Forts.
 GitHub 项目	GitHub-Projekt
 赞助 XStats	XStats unterstützen
+新版本更新	Neue Versionen
+后台发现新版本时通知，每个版本仅提醒一次	Bei im Hintergrund gefundenen Updates einmal pro Version benachrichtigen
+点击查看更新内容并安装。	Klicken, um Neuerungen anzusehen und das Update zu installieren.
diff --git a/Packages/XStatsKit/Sources/Localization/Resources/es.tsv b/Packages/XStatsKit/Sources/Localization/Resources/es.tsv
index 6aed451..7239980 100644
--- a/Packages/XStatsKit/Sources/Localization/Resources/es.tsv
+++ b/Packages/XStatsKit/Sources/Localization/Resources/es.tsv
@@ -1608,3 +1608,6 @@ Homebrew 将按执行时的状态清理旧版本与缓存，不自动移除依
 续	cont.
 GitHub 项目	Proyecto en GitHub
 赞助 XStats	Apoyar XStats
+新版本更新	Nuevas versiones
+后台发现新版本时通知，每个版本仅提醒一次	Notificar una vez por versión al detectar actualizaciones en segundo plano
+点击查看更新内容并安装。	Haz clic para ver las novedades e instalar la actualización.
diff --git a/Packages/XStatsKit/Sources/Localization/Resources/fr.tsv b/Packages/XStatsKit/Sources/Localization/Resources/fr.tsv
index 497de27..3317d4d 100644
--- a/Packages/XStatsKit/Sources/Localization/Resources/fr.tsv
+++ b/Packages/XStatsKit/Sources/Localization/Resources/fr.tsv
@@ -1608,3 +1608,6 @@ Homebrew 将按执行时的状态清理旧版本与缓存，不自动移除依
 续	suite
 GitHub 项目	Projet GitHub
 赞助 XStats	Soutenir XStats
+新版本更新	Nouvelles versions
+后台发现新版本时通知，每个版本仅提醒一次	Notifier une fois par version lorsqu’une mise à jour est détectée en arrière-plan
+点击查看更新内容并安装。	Cliquez pour voir les nouveautés et installer la mise à jour.
diff --git a/Packages/XStatsKit/Sources/Localization/Resources/ja.tsv b/Packages/XStatsKit/Sources/Localization/Resources/ja.tsv
index afc5222..6f50d08 100644
--- a/Packages/XStatsKit/Sources/Localization/Resources/ja.tsv
+++ b/Packages/XStatsKit/Sources/Localization/Resources/ja.tsv
@@ -1608,3 +1608,6 @@ Homebrew 将按执行时的状态清理旧版本与缓存，不自动移除依
 续	続き
 GitHub 项目	GitHub プロジェクト
 赞助 XStats	XStats を支援
+新版本更新	新しいバージョン
+后台发现新版本时通知，每个版本仅提醒一次	バックグラウンドで更新を検出したとき、バージョンごとに一度だけ通知
+点击查看更新内容并安装。	クリックして更新内容を確認し、インストールします。
diff --git a/Packages/XStatsKit/Sources/Localization/Resources/ko.tsv b/Packages/XStatsKit/Sources/Localization/Resources/ko.tsv
index 818bb21..d5d4d67 100644
--- a/Packages/XStatsKit/Sources/Localization/Resources/ko.tsv
+++ b/Packages/XStatsKit/Sources/Localization/Resources/ko.tsv
@@ -1608,3 +1608,6 @@ Homebrew 将按执行时的状态清理旧版本与缓存，不自动移除依
 续	계속
 GitHub 项目	GitHub 프로젝트
 赞助 XStats	XStats 후원
+新版本更新	새 버전 업데이트
+后台发现新版本时通知，每个版本仅提醒一次	백그라운드에서 업데이트를 찾으면 버전마다 한 번만 알림
+点击查看更新内容并安装。	클릭하여 업데이트 내용을 확인하고 설치하세요.
diff --git a/Packages/XStatsKit/Sources/Localization/Resources/zh-Hant.tsv b/Packages/XStatsKit/Sources/Localization/Resources/zh-Hant.tsv
index 4ebfb0a..f982d8b 100644
--- a/Packages/XStatsKit/Sources/Localization/Resources/zh-Hant.tsv
+++ b/Packages/XStatsKit/Sources/Localization/Resources/zh-Hant.tsv
@@ -1609,3 +1609,6 @@ Homebrew 将按执行时的状态清理旧版本与缓存，不自动移除依
 续	續
 GitHub 项目	GitHub 專案
 赞助 XStats	贊助 XStats
+新版本更新	新版本更新
+后台发现新版本时通知，每个版本仅提醒一次	背景發現新版本時通知，每個版本僅提醒一次
+点击查看更新内容并安装。	點擊查看更新內容並安裝。
diff --git a/Packages/XStatsKit/Sources/Localization/Translations.swift b/Packages/XStatsKit/Sources/Localization/Translations.swift
index 9d3a5ba..2cc141e 100644
--- a/Packages/XStatsKit/Sources/Localization/Translations.swift
+++ b/Packages/XStatsKit/Sources/Localization/Translations.swift
@@ -188,6 +188,9 @@ CPU 温度达到 {}，已恢复系统自动控制	CPU reached {}; fans returned
 CPU 温度过高	CPU is too hot
 CPU 负载偏高	CPU load is high
 CPU 负载很高	CPU load is very high
+新版本更新	New version updates
+后台发现新版本时通知，每个版本仅提醒一次	Notify when a background check finds an update, once per version
+点击查看更新内容并安装。	Click to see what’s new and install.
 CPU 过热	CPU Overheating
 CPU：{}（以单核满载为 100%）	CPU: {} (100% = one full core)
 Cloudflare 接入节点（机场代码）	Cloudflare edge location (airport code)
diff --git a/Packages/XStatsKit/Sources/XStatsUI/AppKit/AppController.swift b/Packages/XStatsKit/Sources/XStatsUI/AppKit/AppController.swift
index 188b832..afa37ea 100644
--- a/Packages/XStatsKit/Sources/XStatsUI/AppKit/AppController.swift
+++ b/Packages/XStatsKit/Sources/XStatsUI/AppKit/AppController.swift
@@ -266,6 +266,18 @@ public final class AppController: NSObject, NSApplicationDelegate {
             self?.calendarMenuBar.dismiss()
             self?.updateWindow.show()
         }
+        model.updates.onUpdateAvailable = { [weak self] version in
+            await self?.model.alerts.notifyUpdate(version: version) ?? false
+        }
+        model.alerts.openUpdates = { [weak self] in
+            guard let self else { return }
+            if self.model.updates.release != nil {
+                self.model.updates.onPrompt()
+            } else {
+                // 通知可跨应用重启保留；重新检查后展示当前有效的更新信息。
+                self.checkForUpdatesFromMenu()
+            }
+        }
         DispatchQueue.main.asyncAfter(deadline: .now() + 10) { [weak self] in
             self?.model.updates.checkIfNeeded()
         }
diff --git a/Packages/XStatsKit/Sources/XStatsUI/Settings/SettingsPages.swift b/Packages/XStatsKit/Sources/XStatsUI/Settings/SettingsPages.swift
index 9128a99..2a7b046 100644
--- a/Packages/XStatsKit/Sources/XStatsUI/Settings/SettingsPages.swift
+++ b/Packages/XStatsKit/Sources/XStatsUI/Settings/SettingsPages.swift
@@ -162,8 +162,16 @@ struct NotificationSettings: View {
         }
 
         SettingsGroup(caption: tr("发生这些状况时发送系统通知，点通知打开对应页面")) {
-            ForEach(Array(AlertKind.allCases.enumerated()), id: \.element) { index, kind in
-                GroupRow(showsDivider: index > 0) {
+            GroupRow(showsDivider: false) {
+                SettingRow(title: tr("新版本更新"), subtitle: tr("后台发现新版本时通知，每个版本仅提醒一次"), icon: "arrow.down.circle") {
+                    DSToggle(isOn: Binding(get: { settings.notifyUpdates }, set: { enabled in
+                        settings.notifyUpdates = enabled
+                        if enabled, alerts.authorization == .unknown { alerts.requestAuthorization() }
+                    }), label: tr("新版本更新"))
+                }
+            }
+            ForEach(AlertKind.allCases) { kind in
+                GroupRow {
                     SettingRow(title: kind.title, subtitle: kind.detail, icon: kind.symbol) {
                         DSToggle(isOn: Binding(get: { settings.enabledAlerts.contains(kind) },
                                                set: { on in
diff --git a/Packages/XStatsKit/Sources/XStatsUI/State/AlertController.swift b/Packages/XStatsKit/Sources/XStatsUI/State/AlertController.swift
index f3aac2f..499cbd4 100644
--- a/Packages/XStatsKit/Sources/XStatsUI/State/AlertController.swift
+++ b/Packages/XStatsKit/Sources/XStatsUI/State/AlertController.swift
@@ -114,6 +114,7 @@ public final class AlertController: NSObject {
     public private(set) var authorization: Authorization = .unknown
 
     @ObservationIgnored var openTab: (PanelTab) -> Void = { _ in }
+    @ObservationIgnored var openUpdates: () -> Void = {}
     @ObservationIgnored private let settings: AppSettings
     @ObservationIgnored private let defaults: UserDefaults
     @ObservationIgnored private var trackers: [AlertKind: AlertTracker] = [:]
@@ -271,6 +272,37 @@ public final class AlertController: NSObject {
 
     // MARK: 通知
 
+    /// 默认开启的更新提醒在真正发现版本时才请求权限，不新增轮询或启动时弹窗。
+    func notifyUpdate(version: String) async -> Bool {
+        guard settings.notifyUpdates, let center else { return false }
+        do {
+            let status = await center.notificationSettings().authorizationStatus
+            let granted: Bool
+            if status == .notDetermined {
+                granted = try await center.requestAuthorization(options: [.alert, .sound])
+            } else {
+                granted = status == .authorized || status == .provisional
+            }
+            authorization = granted ? .allowed : .denied
+            // 等待系统授权期间用户可能关闭开关。
+            guard granted, settings.notifyUpdates else { return false }
+            try await center.add(Self.updateNotification(version: version))
+            return true
+        } catch {
+            Log.update.error("更新通知发送失败：\(error.localizedDescription, privacy: .public)")
+            return false
+        }
+    }
+
+    static func updateNotification(version: String) -> UNNotificationRequest {
+        let content = UNMutableNotificationContent()
+        content.title = tr("发现新版本 \(version)")
+        content.body = tr("点击查看更新内容并安装。")
+        content.sound = .default
+        content.userInfo = ["updates": true]
+        return UNNotificationRequest(identifier: "xstats.updateAvailable", content: content, trigger: nil)
+    }
+
     func refreshAuthorization() {
         guard let center else { return }
         center.getNotificationSettings { [weak self] settings in
@@ -337,7 +369,12 @@ extension AlertController: UNUserNotificationCenterDelegate {
     nonisolated public func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse,
                                                    withCompletionHandler completionHandler: @escaping () -> Void) {
         let tab = (response.notification.request.content.userInfo["tab"] as? String).flatMap(PanelTab.init(rawValue:))
+        let updates = response.notification.request.content.userInfo["updates"] as? Bool == true
         completionHandler()
+        if updates {
+            Task { @MainActor [weak self] in self?.openUpdates() }
+            return
+        }
         guard let tab else { return }
         Task { @MainActor [weak self] in self?.openTab(tab) }
     }
diff --git a/Packages/XStatsKit/Sources/XStatsUI/State/AppSettings.swift b/Packages/XStatsKit/Sources/XStatsUI/State/AppSettings.swift
index 75be414..651e121 100644
--- a/Packages/XStatsKit/Sources/XStatsUI/State/AppSettings.swift
+++ b/Packages/XStatsKit/Sources/XStatsUI/State/AppSettings.swift
@@ -603,6 +603,10 @@ public final class AppSettings {
     public var publicIPLookup: Bool {
         didSet { defaults.set(publicIPLookup, forKey: Keys.publicIPLookup) }
     }
+    /// 自动检查发现新版本时发送系统通知，默认开启。
+    public var notifyUpdates: Bool {
+        didSet { defaults.set(notifyUpdates, forKey: Keys.notifyUpdates) }
+    }
     /// 打开了系统通知的状况
     public var enabledAlerts: Set<AlertKind> {
         didSet { defaults.set(enabledAlerts.map(\.rawValue).sorted(), forKey: Keys.enabledAlerts) }
@@ -775,6 +779,7 @@ public final class AppSettings {
         hotKeys = Dictionary(uniqueKeysWithValues: storedHotKeys.compactMap { key, value in
             HotKeyAction(rawValue: key).map { ($0, value) }
         })
+        notifyUpdates = defaults.object(forKey: Keys.notifyUpdates) as? Bool ?? true
         enabledAlerts = Set(defaults.stringArray(forKey: Keys.enabledAlerts)?.compactMap(AlertKind.init(rawValue:)) ?? [])
         alertCPUTemperature = Self.alertTemperatureOptions.contains(defaults.integer(forKey: Keys.alertCPUTemperature))
             ? defaults.integer(forKey: Keys.alertCPUTemperature) : 95
@@ -872,6 +877,7 @@ public final class AppSettings {
         static let hotKeys = "hotKeys"
         static let language = "language"
         static let enabledAlerts = "enabledAlerts"
+        static let notifyUpdates = "notifyUpdates"
         static let alertCPUTemperature = "alertCPUTemperature"
         static let alertCPULoad = "alertCPULoad"
         static let cpuChartSeconds = "cpuChartSeconds"
diff --git a/Packages/XStatsKit/Sources/XStatsUI/State/SettingsDocument.swift b/Packages/XStatsKit/Sources/XStatsUI/State/SettingsDocument.swift
index 45e6102..72cc7d9 100644
--- a/Packages/XStatsKit/Sources/XStatsUI/State/SettingsDocument.swift
+++ b/Packages/XStatsKit/Sources/XStatsUI/State/SettingsDocument.swift
@@ -49,6 +49,7 @@ public struct SettingsDocument: Codable, Equatable, Sendable {
     public var probeTarget: String?
     public var publicIPLookup: Bool?
     public var enabledAlerts: [String]?
+    public var notifyUpdates: Bool?
     public var alertCPUTemperature: Int?
     public var alertCPULoad: Int?
     public var language: String?
@@ -99,6 +100,7 @@ extension AppSettings {
         doc.probeTarget = probeTarget.rawValue
         doc.publicIPLookup = publicIPLookup
         doc.enabledAlerts = enabledAlerts.map(\.rawValue).sorted()
+        doc.notifyUpdates = notifyUpdates
         doc.alertCPUTemperature = alertCPUTemperature
         doc.alertCPULoad = alertCPULoad
         doc.language = language.rawValue
@@ -121,6 +123,7 @@ extension AppSettings {
             value.flatMap { options.contains($0) ? $0 : nil }
         }
 
+        assign(\.notifyUpdates, doc.notifyUpdates)
         assign(\.calendarEnabled, doc.calendarEnabled)
         assign(\.calendarPreferences, doc.calendarPreferences)
         assign(\.restEnabled, doc.restEnabled)
diff --git a/Packages/XStatsKit/Sources/XStatsUI/State/UpdateController.swift b/Packages/XStatsKit/Sources/XStatsUI/State/UpdateController.swift
index fbd49f5..e8dcc21 100644
--- a/Packages/XStatsKit/Sources/XStatsUI/State/UpdateController.swift
+++ b/Packages/XStatsKit/Sources/XStatsUI/State/UpdateController.swift
@@ -28,8 +28,10 @@ public final class UpdateController {
         didSet { defaults.set(skippedVersion, forKey: Keys.skippedVersion) }
     }
 
-    /// 自动检查发现未跳过的新版本时调用，由 AppController 打开升级提示窗口
+    /// 手动检查发现新版本时调用，由 AppController 打开升级提示窗口
     @ObservationIgnored var onPrompt: () -> Void = {}
+    /// 后台发现新版本时请求系统通知；成功提交后才记录去重状态。
+    @ObservationIgnored var onUpdateAvailable: (String) async -> Bool = { _ in false }
     /// 安装完成后退出应用，等进程结束再打开新版
     @ObservationIgnored var terminate: () -> Void = { NSApp.terminate(nil) }
 
@@ -37,6 +39,7 @@ public final class UpdateController {
     @ObservationIgnored private let defaults: UserDefaults
     @ObservationIgnored private var task: Task<Void, Never>?
     @ObservationIgnored private let launchedAt: Date
+    @ObservationIgnored private var isNotifying = false
 
     init(settings: AppSettings, defaults: UserDefaults = .standard, launchedAt: Date = Date()) {
         self.settings = settings
@@ -93,8 +96,7 @@ public final class UpdateController {
                 release = latest
                 phase = .available
                 Log.update.notice("发现新版本 \(latest.version, privacy: .public)")
-                // 手动检查时总是提示；自动检查时跳过用户选择忽略的版本
-                if userInitiated || (!suppressPrompt && latest.version != skippedVersion) { onPrompt() }
+                await announceUpdate(version: latest.version, userInitiated: userInitiated, suppressPrompt: suppressPrompt)
             case .failure(let error):
                 Log.update.error("检查更新失败：\(error.localizedDescription, privacy: .public)")
                 // 自动检查失败不打扰用户，只在关于页里显示
@@ -103,6 +105,21 @@ public final class UpdateController {
         }
     }
 
+    /// 手动检查始终展示结果；后台通知遵循静默策略、开关、跳过版本及跨重启去重。
+    func announceUpdate(version: String, userInitiated: Bool, suppressPrompt: Bool) async {
+        if userInitiated {
+            onPrompt()
+            return
+        }
+        guard !suppressPrompt, settings.notifyUpdates, version != skippedVersion,
+              !isNotifying else { return }
+        if let last = defaults.string(forKey: Keys.notifiedVersion), !UpdateFeed.isNewer(version, than: last) { return }
+        // 通知权限弹窗期间允许查看更新，但不能重复提交后台通知。
+        isNotifying = true
+        defer { isNotifying = false }
+        if await onUpdateAvailable(version) { defaults.set(version, forKey: Keys.notifiedVersion) }
+    }
+
     private static func fetch(currentVersion: String) async -> Result<UpdateRelease, UpdateError> {
         do {
             let installationID = try InstallationIdentity().hashedID()
@@ -248,5 +265,6 @@ public final class UpdateController {
     private enum Keys {
         static let lastChecked = "updateLastChecked"
         static let skippedVersion = "updateSkippedVersion"
+        static let notifiedVersion = "updateNotifiedVersion"
     }
 }
diff --git a/Packages/XStatsKit/Tests/XStatsUITests/UpdateNotificationTests.swift b/Packages/XStatsKit/Tests/XStatsUITests/UpdateNotificationTests.swift
new file mode 100644
index 0000000..f6dff0d
--- /dev/null
+++ b/Packages/XStatsKit/Tests/XStatsUITests/UpdateNotificationTests.swift
@@ -0,0 +1,103 @@
+// Copyright (C) 2026 ysicing
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import Foundation
+import Testing
+@testable import XStatsUI
+
+@MainActor
+struct UpdateNotificationTests {
+    private let defaults = UserDefaults(suiteName: "UpdateNotificationTests.\(UUID().uuidString)")!
+
+    @Test func preferenceDefaultsOnAndPreservesAnExplicitOptOut() throws {
+        // 已有安装的其他通知偏好不影响新开关的默认值。
+        defaults.set([String](), forKey: "enabledAlerts")
+        let settings = AppSettings(defaults: defaults)
+        #expect(settings.notifyUpdates)
+        settings.notifyUpdates = false
+        #expect(!AppSettings(defaults: defaults).notifyUpdates)
+        let data = try JSONEncoder().encode(settings.exportDocument())
+        let restored = AppSettings(defaults: UserDefaults(suiteName: UUID().uuidString)!)
+        restored.apply(try JSONDecoder().decode(SettingsDocument.self, from: data))
+        #expect(!restored.notifyUpdates)
+        restored.apply(try JSONDecoder().decode(SettingsDocument.self, from: Data("{}".utf8)))
+        #expect(!restored.notifyUpdates)
+    }
+
+    @Test func successfulNotificationIsDeduplicatedAcrossRestarts() async {
+        let settings = AppSettings(defaults: defaults)
+        let first = UpdateController(settings: settings, defaults: defaults)
+        var versions: [String] = []
+        first.onUpdateAvailable = { versions.append($0); return true }
+        await first.announceUpdate(version: "1.0.0", userInitiated: false, suppressPrompt: false)
+        await first.announceUpdate(version: "1.0.0", userInitiated: false, suppressPrompt: false)
+        let restarted = UpdateController(settings: settings, defaults: defaults)
+        restarted.onUpdateAvailable = { versions.append($0); return true }
+        await restarted.announceUpdate(version: "1.0.0", userInitiated: false, suppressPrompt: false)
+        await restarted.announceUpdate(version: "1.0.1", userInitiated: false, suppressPrompt: false)
+        await restarted.announceUpdate(version: "1.0.0", userInitiated: false, suppressPrompt: false)
+        #expect(versions == ["1.0.0", "1.0.1"])
+    }
+
+    @Test func deniedOrFailedSubmissionCanBeRetried() async {
+        let controller = UpdateController(settings: AppSettings(defaults: defaults), defaults: defaults)
+        var attempts = 0
+        controller.onUpdateAvailable = { _ in attempts += 1; return attempts > 1 }
+        for _ in 0..<3 {
+            await controller.announceUpdate(version: "1.0.0", userInitiated: false, suppressPrompt: false)
+        }
+        #expect(attempts == 2)
+    }
+
+    @Test func backgroundRespectsOptOutQuietModeAndSkippedVersion() async {
+        defaults.set("1.0.0", forKey: "updateSkippedVersion")
+        let settings = AppSettings(defaults: defaults)
+        let controller = UpdateController(settings: settings, defaults: defaults)
+        var versions: [String] = []
+        controller.onUpdateAvailable = { versions.append($0); return true }
+        settings.notifyUpdates = false
+        await controller.announceUpdate(version: "1.0.1", userInitiated: false, suppressPrompt: false)
+        settings.notifyUpdates = true
+        await controller.announceUpdate(version: "1.0.1", userInitiated: false, suppressPrompt: true)
+        await controller.announceUpdate(version: "1.0.0", userInitiated: false, suppressPrompt: false)
+        #expect(versions.isEmpty)
+        await controller.announceUpdate(version: "1.0.1", userInitiated: false, suppressPrompt: false)
+        #expect(versions == ["1.0.1"])
+    }
+
+    @Test func manualCheckAlwaysPresentsWithoutSendingNotification() async {
+        defaults.set("1.0.0", forKey: "updateSkippedVersion")
+        defaults.set("1.0.0", forKey: "updateNotifiedVersion")
+        let settings = AppSettings(defaults: defaults)
+        settings.notifyUpdates = false
+        let controller = UpdateController(settings: settings, defaults: defaults)
+        var prompts = 0
+        var notifications = 0
+        controller.onPrompt = { prompts += 1 }
+        controller.onUpdateAvailable = { _ in notifications += 1; return true }
+        await controller.announceUpdate(version: "1.0.0", userInitiated: true, suppressPrompt: true)
+        #expect(prompts == 1)
+        #expect(notifications == 0)
+    }
+
+    @Test func pendingAuthorizationDoesNotAllowDuplicateNotifications() async {
+        let controller = UpdateController(settings: AppSettings(defaults: defaults), defaults: defaults)
+        var notifications = 0
+        controller.onUpdateAvailable = { [weak controller] version in
+            notifications += 1
+            await controller?.announceUpdate(version: version, userInitiated: false, suppressPrompt: false)
+            return true
+        }
+        await controller.announceUpdate(version: "1.0.0", userInitiated: false, suppressPrompt: false)
+        #expect(notifications == 1)
+    }
+
+    @Test func notificationRoutesToUpdatesAndReplacesPreviousVersion() {
+        let first = AlertController.updateNotification(version: "1.0.0")
+        let next = AlertController.updateNotification(version: "1.0.1")
+        #expect(first.identifier == next.identifier)
+        #expect(next.content.title.contains("1.0.1"))
+        #expect(next.content.userInfo["updates"] as? Bool == true)
+        #expect(next.trigger == nil)
+    }
+}