diff --git a/README.md b/README.md
index 91cf69c..dc5e316 100644
--- a/README.md
+++ b/README.md
@@ -71,6 +71,13 @@ rollback themselves. The macOS window appears in the Dock and Cmd-Tab, follows
 the system language by default, and can switch between Simplified Chinese and
 English in Settings.
 
+Both native workbenches expose **About & Updates**. The first launch on each
+local calendar day makes at most one non-blocking request to the official
+`MHToolkit/mh-save-sync` latest-release endpoint; users may also check
+manually. An unavailable GitHub connection never blocks conversion. A newer
+release dialog shows its version, publication date, release notes, and official
+link. No save bytes or selected paths are sent with this request.
+
 The workbenches provide four **guided but non-blocking** stages: input and
 inspection, optional shared data, Dry Run, then write or rollback. Completing
 one stage reveals the recommended next action (for example, inspect then
diff --git a/README.zh-CN.md b/README.zh-CN.md
index 4622ba6..6aec25d 100644
--- a/README.zh-CN.md
+++ b/README.zh-CN.md
@@ -53,6 +53,11 @@ JSON 报告；不会在 UI 内重写字节转换、备份、manifest、模拟器
 macOS 窗口会正常出现于 Dock 和 Cmd-Tab；默认跟随系统语言，也可在设置中切换简体中文或
 English。
 
+两个原生工作台都提供“**关于与更新**”。每个本地自然日首次启动最多向
+`MHToolkit/mh-save-sync` 官方 latest-release 接口发起一次非阻塞请求，也可手动检查；
+GitHub 不可访问时绝不会阻塞转换。发现新版时会显示版本、发布日期、Release 说明和官方
+链接。该请求不会上传任何存档字节或用户所选路径。
+
 工作台提供四个**有引导、但不强制**的阶段：输入与检查、可选共享数据、Dry Run、写入或
 回滚。完成一个阶段后会显示推荐的下一步操作（例如检查完成后配置可选数据），但玩家仍可
 返回前一阶段，或跳过可选组件。该引导不会额外执行任何转换。
diff --git a/apps/mh3g-save-converter-macos/README.md b/apps/mh3g-save-converter-macos/README.md
index 3b4d2f5..7871cd5 100644
--- a/apps/mh3g-save-converter-macos/README.md
+++ b/apps/mh3g-save-converter-macos/README.md
@@ -31,6 +31,23 @@ Normal conversion uses a single-file manifest; compatibility repair uses
 `.mh3g-compatibility-repair-<UUID>.json` and `rollback-repair`. Quit Nemessix,
 Azahar, and Cemu before any write or rollback.
 
+The optional housekeeper gallery/movie migration never creates or replaces a
+shared `system` from the 3DS file alone. Select both the 3DS source `system` and
+an existing initialized Cemu `system`; the converter unions only the known
+gallery/movie flags and preserves every other Cemu byte, including data shared
+by the other character slots.
+
+## Updates
+
+The About & Updates section resolves the latest stable tag through the official
+`MHToolkit/mh-save-sync` GitHub release page and reads its official Atom release
+feed. This path does not consume the shared anonymous GitHub API quota; the
+Release API remains a fallback. The first launch on each local calendar day
+makes at most one silent attempt. A blocked or unavailable GitHub connection
+never blocks the window or any local conversion; manual checks show the error
+and may be retried. When a newer release exists, the app shows its title,
+publication date, release notes, and official release link.
+
 ## Local verification
 
 ```bash
diff --git a/apps/mh3g-save-converter-macos/README.zh-CN.md b/apps/mh3g-save-converter-macos/README.zh-CN.md
index 883491f..2b5da83 100644
--- a/apps/mh3g-save-converter-macos/README.zh-CN.md
+++ b/apps/mh3g-save-converter-macos/README.zh-CN.md
@@ -23,6 +23,19 @@ sidecar 并展示 JSON 报告，不在 Swift 中重复实现存档转换。
 使用 `.mh3g-compatibility-repair-<UUID>.json` 并通过 `rollback-repair` 总体回滚。
 执行写入或回滚前必须退出 Nemessix、Azahar 和 Cemu。
 
+可选的管家画廊/动画迁移不会只凭 3DS `system` 新建或整文件覆盖共享
+`system`。必须同时选择 3DS 源 `system` 和已存在、已初始化的 Cemu `system`；
+转换器只合并已知画廊/动画标记，其他 Cemu 字节（包括其他角色槽位共享数据）
+全部保留。
+
+## 更新检查
+
+“关于与更新”会通过 `MHToolkit/mh-save-sync` 官方 GitHub Release 页面确认最新
+正式版 tag，并读取官方 Atom Release feed。该主路径不消耗共享的 GitHub 匿名
+API 配额，Release API 仅作为备用。每个本地自然日首次启动最多静默尝试一次；
+GitHub 无法访问时不会阻塞窗口，也不会影响任何本地转换。手动检查会展示错误并
+允许重试；发现新版本时会显示版本名、发布日期、Release 说明和官方发布链接。
+
 ## 本地验证
 
 ```bash
diff --git a/apps/mh3g-save-converter-macos/Sources/ConverterPresentation/Localization.swift b/apps/mh3g-save-converter-macos/Sources/ConverterPresentation/Localization.swift
index 87f545b..9f41529 100644
--- a/apps/mh3g-save-converter-macos/Sources/ConverterPresentation/Localization.swift
+++ b/apps/mh3g-save-converter-macos/Sources/ConverterPresentation/Localization.swift
@@ -292,6 +292,20 @@ public enum ConverterCopy {
         "WorkflowState.Failure": "操作失败",
         "Settings.BundledSidecar": "打包时使用内置 sidecar",
         "Settings.Development": "开发版本",
+        "Update.About": "关于与更新",
+        "Update.CurrentVersion": "当前版本",
+        "Update.Check": "检查更新",
+        "Update.Checking": "正在连接 GitHub…",
+        "Update.UpToDate": "已经是最新版（GitHub：%@）",
+        "Update.Available": "发现新版本 %@，请在弹窗中查看更新说明。",
+        "Update.Failed": "无法检查更新",
+        "Update.NetworkNote": "每天首次启动会静默检查一次 GitHub Release；网络不可用时不会阻塞或影响任何本地存档操作。也可以随时手动重试。",
+        "Update.AvailableTitle": "发现新版本",
+        "Update.VersionSummary": "当前 %@ · 最新 %@",
+        "Update.ReleaseNotes": "更新说明",
+        "Update.NoReleaseNotes": "该版本未提供更新说明。",
+        "Update.Later": "稍后",
+        "Update.OpenRelease": "打开发布页面",
     ]
 
     private static let english: [String: String] = [
@@ -482,6 +496,20 @@ public enum ConverterCopy {
         "WorkflowState.Failure": "Operation failed",
         "Settings.BundledSidecar": "Bundled sidecar when packaged",
         "Settings.Development": "development",
+        "Update.About": "About & Updates",
+        "Update.CurrentVersion": "Current version",
+        "Update.Check": "Check for Updates",
+        "Update.Checking": "Contacting GitHub…",
+        "Update.UpToDate": "You are up to date (GitHub: %@)",
+        "Update.Available": "Version %@ is available. Review its release notes in the update window.",
+        "Update.Failed": "Unable to check for updates",
+        "Update.NetworkNote": "The first launch each day silently checks GitHub Releases once. An unavailable network never blocks or changes any local save operation, and you can retry manually at any time.",
+        "Update.AvailableTitle": "Update Available",
+        "Update.VersionSummary": "Current %@ · Latest %@",
+        "Update.ReleaseNotes": "Release notes",
+        "Update.NoReleaseNotes": "No release notes were provided for this version.",
+        "Update.Later": "Later",
+        "Update.OpenRelease": "Open Release Page",
     ]
 
     /// The complete set of copy IDs rendered by the SwiftUI workbench.  Tests
diff --git a/apps/mh3g-save-converter-macos/Sources/ConverterPresentation/UpdateChecking.swift b/apps/mh3g-save-converter-macos/Sources/ConverterPresentation/UpdateChecking.swift
new file mode 100644
index 0000000..82ab9db
--- /dev/null
+++ b/apps/mh3g-save-converter-macos/Sources/ConverterPresentation/UpdateChecking.swift
@@ -0,0 +1,268 @@
+import Foundation
+
+public struct ConverterSemanticVersion: Comparable, Equatable, Sendable, CustomStringConvertible {
+    public let components: [Int]
+
+    public init?(_ value: String) {
+        let normalized = value
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+            .trimmingPrefix("v")
+            .split(separator: "+", maxSplits: 1, omittingEmptySubsequences: true)[0]
+            .split(separator: "-", maxSplits: 1, omittingEmptySubsequences: true)[0]
+        let parts = normalized.split(separator: ".", omittingEmptySubsequences: false)
+        guard !parts.isEmpty,
+              parts.allSatisfy({ !$0.isEmpty && $0.allSatisfy(\.isNumber) }),
+              parts.allSatisfy({ Int($0) != nil })
+        else {
+            return nil
+        }
+        components = parts.map { Int($0)! }
+    }
+
+    public static func < (lhs: Self, rhs: Self) -> Bool {
+        let count = max(lhs.components.count, rhs.components.count)
+        for index in 0..<count {
+            let left = index < lhs.components.count ? lhs.components[index] : 0
+            let right = index < rhs.components.count ? rhs.components[index] : 0
+            if left != right {
+                return left < right
+            }
+        }
+        return false
+    }
+
+    public static func == (lhs: Self, rhs: Self) -> Bool {
+        !(lhs < rhs) && !(rhs < lhs)
+    }
+
+    public var description: String {
+        components.map(String.init).joined(separator: ".")
+    }
+}
+
+public struct GitHubConverterRelease: Codable, Equatable, Identifiable, Sendable {
+    public let tagName: String
+    public let name: String?
+    public let body: String?
+    public let htmlURL: URL
+    public let publishedAt: String?
+    public let draft: Bool
+    public let prerelease: Bool
+
+    public var id: String { tagName }
+
+    public var isOfficialStableRelease: Bool {
+        !draft
+            && !prerelease
+            && htmlURL.scheme == "https"
+            && htmlURL.host?.lowercased() == "github.com"
+            && htmlURL.path.hasPrefix("/MHToolkit/mh-save-sync/releases/")
+    }
+
+    public init(
+        tagName: String,
+        name: String?,
+        body: String?,
+        htmlURL: URL,
+        publishedAt: String?,
+        draft: Bool,
+        prerelease: Bool
+    ) {
+        self.tagName = tagName
+        self.name = name
+        self.body = body
+        self.htmlURL = htmlURL
+        self.publishedAt = publishedAt
+        self.draft = draft
+        self.prerelease = prerelease
+    }
+
+    enum CodingKeys: String, CodingKey {
+        case tagName = "tag_name"
+        case name
+        case body
+        case htmlURL = "html_url"
+        case publishedAt = "published_at"
+        case draft
+        case prerelease
+    }
+}
+
+public enum ConverterUpdateDecision: Equatable, Sendable {
+    case updateAvailable
+    case upToDate
+    case invalidVersion
+
+    public static func decide(current: String, latest: String) -> Self {
+        guard let currentVersion = ConverterSemanticVersion(current),
+              let latestVersion = ConverterSemanticVersion(latest)
+        else {
+            return .invalidVersion
+        }
+        return currentVersion < latestVersion ? .updateAvailable : .upToDate
+    }
+}
+
+public enum GitHubReleaseAtomFeed {
+    public static func stableRelease(from data: Data, expectedReleaseURL: URL) throws -> GitHubConverterRelease {
+        guard isOfficialTagURL(expectedReleaseURL),
+              let tagName = expectedReleaseURL.lastPathComponent.removingPercentEncoding,
+              ConverterSemanticVersion(tagName) != nil
+        else {
+            throw GitHubReleaseAtomFeedError.invalidReleaseURL
+        }
+
+        let delegate = GitHubReleaseAtomParser()
+        let parser = XMLParser(data: data)
+        parser.delegate = delegate
+        guard parser.parse(), parser.parserError == nil else {
+            throw GitHubReleaseAtomFeedError.invalidXML
+        }
+        guard let entry = delegate.entries.first(where: {
+            $0.link?.absoluteString == expectedReleaseURL.absoluteString
+        }) else {
+            throw GitHubReleaseAtomFeedError.releaseNotFound
+        }
+
+        let release = GitHubConverterRelease(
+            tagName: tagName,
+            name: entry.title.nilIfBlank,
+            body: plainText(fromHTML: entry.content).nilIfBlank,
+            htmlURL: expectedReleaseURL,
+            publishedAt: entry.updated.nilIfBlank,
+            draft: false,
+            prerelease: false
+        )
+        guard release.isOfficialStableRelease else {
+            throw GitHubReleaseAtomFeedError.invalidReleaseURL
+        }
+        return release
+    }
+
+    public static func isOfficialTagURL(_ url: URL) -> Bool {
+        url.scheme == "https"
+            && url.host?.lowercased() == "github.com"
+            && url.query == nil
+            && url.fragment == nil
+            && url.path.hasPrefix("/MHToolkit/mh-save-sync/releases/tag/")
+            && url.pathComponents.count == 6
+    }
+
+    private static func plainText(fromHTML html: String) -> String {
+        var text = html.replacingOccurrences(
+            of: #"(?i)<li(?:\s[^>]*)?>"#,
+            with: "• ",
+            options: .regularExpression
+        )
+        text = text.replacingOccurrences(
+            of: #"(?i)<br\s*/?>|</li\s*>|</p\s*>|</h[1-6]\s*>|</blockquote\s*>|</pre\s*>"#,
+            with: "\n",
+            options: .regularExpression
+        )
+        text = text.replacingOccurrences(of: #"<[^>]+>"#, with: "", options: .regularExpression)
+        return text
+            .split(whereSeparator: \Character.isNewline)
+            .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+            .filter { !$0.isEmpty }
+            .joined(separator: "\n")
+            .prefix(32_000)
+            .description
+    }
+}
+
+private enum GitHubReleaseAtomFeedError: Error {
+    case invalidReleaseURL
+    case invalidXML
+    case releaseNotFound
+}
+
+private final class GitHubReleaseAtomParser: NSObject, XMLParserDelegate {
+    struct Entry {
+        var title = ""
+        var updated = ""
+        var content = ""
+        var link: URL?
+    }
+
+    private(set) var entries: [Entry] = []
+    private var currentEntry: Entry?
+    private var capturedElement: String?
+    private var characters = ""
+
+    func parser(
+        _ parser: XMLParser,
+        didStartElement elementName: String,
+        namespaceURI: String?,
+        qualifiedName qName: String?,
+        attributes attributeDict: [String: String] = [:]
+    ) {
+        if elementName == "entry" {
+            currentEntry = Entry()
+            return
+        }
+        guard currentEntry != nil else { return }
+        if elementName == "link",
+           attributeDict["rel"] == "alternate",
+           let href = attributeDict["href"],
+           let url = URL(string: href)
+        {
+            currentEntry?.link = url
+        } else if elementName == "title" || elementName == "updated" || elementName == "content" {
+            capturedElement = elementName
+            characters = ""
+        }
+    }
+
+    func parser(_ parser: XMLParser, foundCharacters string: String) {
+        guard capturedElement != nil else { return }
+        characters += string
+    }
+
+    func parser(
+        _ parser: XMLParser,
+        didEndElement elementName: String,
+        namespaceURI: String?,
+        qualifiedName qName: String?
+    ) {
+        if elementName == capturedElement {
+            switch elementName {
+            case "title":
+                currentEntry?.title = characters.trimmingCharacters(in: .whitespacesAndNewlines)
+            case "updated":
+                currentEntry?.updated = characters.trimmingCharacters(in: .whitespacesAndNewlines)
+            case "content":
+                currentEntry?.content = characters
+            default:
+                break
+            }
+            capturedElement = nil
+            characters = ""
+        }
+        if elementName == "entry", let currentEntry {
+            entries.append(currentEntry)
+            self.currentEntry = nil
+        }
+    }
+}
+
+public enum DailyUpdateCheckGate {
+    public static func shouldCheck(
+        lastAttempt: Date?,
+        now: Date,
+        calendar: Calendar = .current
+    ) -> Bool {
+        guard let lastAttempt else { return true }
+        return !calendar.isDate(lastAttempt, inSameDayAs: now)
+    }
+}
+
+private extension String {
+    var nilIfBlank: String? {
+        let trimmed = trimmingCharacters(in: .whitespacesAndNewlines)
+        return trimmed.isEmpty ? nil : trimmed
+    }
+
+    func trimmingPrefix(_ prefix: Character) -> String {
+        first == prefix ? String(dropFirst()) : self
+    }
+}
diff --git a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/ConversionWorkbenchView.swift b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/ConversionWorkbenchView.swift
index 63bb595..f9289ae 100644
--- a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/ConversionWorkbenchView.swift
+++ b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/ConversionWorkbenchView.swift
@@ -5,6 +5,7 @@ struct ConversionWorkbenchView: View {
     @Binding var localeOverride: String
     @State private var selectedNavigation: ConverterNavigation? = .input
     @State private var workflow = ConversionWorkflow(executable: ConverterExecutableLocator.locate())
+    @StateObject private var updateChecker = GitHubUpdateChecker()
     @Environment(\.accessibilityReduceMotion) private var reduceMotion
 
     private var language: ConverterLanguage {
@@ -50,6 +51,16 @@ struct ConversionWorkbenchView: View {
             // Navigation is controlled by native split-view selection.  The
             // content changes are brief and do not disable any other control.
         }
+        .task {
+            await updateChecker.checkAutomaticallyIfNeeded()
+        }
+        .sheet(item: $updateChecker.availableRelease) { release in
+            UpdateReleaseView(
+                release: release,
+                currentVersion: updateChecker.currentVersion,
+                language: language
+            )
+        }
     }
 
     @ViewBuilder
@@ -68,7 +79,12 @@ struct ConversionWorkbenchView: View {
         case .experimentalCEC:
             ExperimentalCECView(workflow: workflow, language: language)
         case .settings:
-            SettingsView(localeOverride: $localeOverride, workflow: workflow, language: language)
+            SettingsView(
+                localeOverride: $localeOverride,
+                workflow: workflow,
+                updateChecker: updateChecker,
+                language: language
+            )
         }
     }
 }
diff --git a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/GitHubUpdateChecker.swift b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/GitHubUpdateChecker.swift
new file mode 100644
index 0000000..253078f
--- /dev/null
+++ b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/GitHubUpdateChecker.swift
@@ -0,0 +1,201 @@
+import ConverterPresentation
+import Foundation
+
+enum UpdateCheckStatus: Equatable {
+    case idle
+    case checking
+    case upToDate(String)
+    case updateAvailable(String)
+    case failed(String)
+}
+
+@MainActor
+final class GitHubUpdateChecker: ObservableObject {
+    static let releaseEndpoint = URL(string: "https://api.github.com/repos/MHToolkit/mh-save-sync/releases/latest")!
+    static let releaseWebEndpoint = URL(string: "https://github.com/MHToolkit/mh-save-sync/releases/latest")!
+    static let releaseAtomEndpoint = URL(string: "https://github.com/MHToolkit/mh-save-sync/releases.atom")!
+    static let lastAttemptDefaultsKey = "MH3GSaveConverter.LastUpdateCheckAttempt"
+
+    @Published private(set) var status: UpdateCheckStatus = .idle
+    @Published var availableRelease: GitHubConverterRelease?
+
+    let currentVersion: String
+
+    private let session: URLSession
+    private let defaults: UserDefaults
+
+    init(
+        currentVersion: String? = nil,
+        session: URLSession? = nil,
+        defaults: UserDefaults = .standard
+    ) {
+        self.currentVersion = currentVersion ?? Self.bundleVersion
+        self.defaults = defaults
+        if let session {
+            self.session = session
+        } else {
+            let configuration = URLSessionConfiguration.ephemeral
+            configuration.timeoutIntervalForRequest = 8
+            configuration.timeoutIntervalForResource = 12
+            self.session = URLSession(configuration: configuration)
+        }
+    }
+
+    var isChecking: Bool {
+        status == .checking
+    }
+
+    func checkAutomaticallyIfNeeded(now: Date = .now, calendar: Calendar = .current) async {
+        guard !isChecking,
+              DailyUpdateCheckGate.shouldCheck(
+                  lastAttempt: defaults.object(forKey: Self.lastAttemptDefaultsKey) as? Date,
+                  now: now,
+                  calendar: calendar
+              )
+        else {
+            return
+        }
+
+        // Persist before networking. A blocked or offline GitHub request must
+        // not be repeated on every launch during the same local calendar day.
+        defaults.set(now, forKey: Self.lastAttemptDefaultsKey)
+        await performCheck(manual: false)
+    }
+
+    func checkManually() async {
+        guard !isChecking else { return }
+        await performCheck(manual: true)
+    }
+
+    private func performCheck(manual: Bool) async {
+        status = .checking
+        do {
+            let release = try await fetchLatestRelease()
+            try validate(release: release)
+            switch ConverterUpdateDecision.decide(current: currentVersion, latest: release.tagName) {
+            case .updateAvailable:
+                availableRelease = release
+                status = .updateAvailable(release.tagName)
+            case .upToDate:
+                availableRelease = nil
+                status = .upToDate(release.tagName)
+            case .invalidVersion:
+                throw UpdateCheckError.invalidVersion
+            }
+        } catch {
+            availableRelease = nil
+            // Automatic checks stay silent and never obstruct the local save
+            // workflow. Manual checks retain a diagnostic for the About pane.
+            status = manual ? .failed(error.localizedDescription) : .idle
+        }
+    }
+
+    private func fetchLatestRelease() async throws -> GitHubConverterRelease {
+        do {
+            return try await fetchLatestReleaseFromWebFeed()
+        } catch {
+            let webFailure = error.localizedDescription
+            do {
+                return try await fetchLatestReleaseFromAPI()
+            } catch {
+                throw UpdateCheckError.allSourcesUnavailable(
+                    web: webFailure,
+                    api: error.localizedDescription
+                )
+            }
+        }
+    }
+
+    private func fetchLatestReleaseFromWebFeed() async throws -> GitHubConverterRelease {
+        var latestRequest = configuredRequest(url: Self.releaseWebEndpoint, accept: "text/html")
+        // One byte is enough: URLSession follows GitHub's /releases/latest
+        // redirect, and the final response URL carries the stable tag. This
+        // avoids downloading the full release page.
+        latestRequest.setValue("bytes=0-0", forHTTPHeaderField: "Range")
+        let (redirectProbe, latestResponse) = try await session.data(for: latestRequest)
+        guard let latestHTTP = latestResponse as? HTTPURLResponse,
+              latestHTTP.statusCode == 200 || latestHTTP.statusCode == 206,
+              redirectProbe.count <= 2 * 1_024 * 1_024,
+              let stableReleaseURL = latestHTTP.url,
+              GitHubReleaseAtomFeed.isOfficialTagURL(stableReleaseURL)
+        else {
+            throw UpdateCheckError.invalidResponse(source: "GitHub release page")
+        }
+
+        let atomRequest = configuredRequest(url: Self.releaseAtomEndpoint, accept: "application/atom+xml")
+        let (atomData, atomResponse) = try await session.data(for: atomRequest)
+        guard let atomHTTP = atomResponse as? HTTPURLResponse, atomHTTP.statusCode == 200 else {
+            throw UpdateCheckError.invalidResponse(source: "GitHub release feed")
+        }
+        guard atomData.count <= 2 * 1_024 * 1_024 else {
+            throw UpdateCheckError.responseTooLarge(source: "GitHub release feed")
+        }
+        return try GitHubReleaseAtomFeed.stableRelease(
+            from: atomData,
+            expectedReleaseURL: stableReleaseURL
+        )
+    }
+
+    private func fetchLatestReleaseFromAPI() async throws -> GitHubConverterRelease {
+        var request = configuredRequest(url: Self.releaseEndpoint, accept: "application/vnd.github+json")
+        request.setValue("2022-11-28", forHTTPHeaderField: "X-GitHub-Api-Version")
+        let (data, response) = try await session.data(for: request)
+        guard let http = response as? HTTPURLResponse, http.statusCode == 200 else {
+            let status = (response as? HTTPURLResponse)?.statusCode
+            throw UpdateCheckError.invalidResponse(
+                source: status.map { "GitHub Release API (HTTP \($0))" } ?? "GitHub Release API"
+            )
+        }
+        guard data.count <= 2 * 1_024 * 1_024 else {
+            throw UpdateCheckError.responseTooLarge(source: "GitHub Release API")
+        }
+        let release = try JSONDecoder().decode(GitHubConverterRelease.self, from: data)
+        try validate(release: release)
+        return release
+    }
+
+    private func configuredRequest(url: URL, accept: String) -> URLRequest {
+        var request = URLRequest(url: url)
+        request.timeoutInterval = 8
+        request.setValue(accept, forHTTPHeaderField: "Accept")
+        request.setValue("MH3GSaveConverter/\(safeUserAgentVersion)", forHTTPHeaderField: "User-Agent")
+        return request
+    }
+
+    private func validate(release: GitHubConverterRelease) throws {
+        guard release.isOfficialStableRelease else {
+            throw UpdateCheckError.invalidRelease
+        }
+    }
+
+    private var safeUserAgentVersion: String {
+        ConverterSemanticVersion(currentVersion)?.description ?? "0.0.0"
+    }
+
+    private static var bundleVersion: String {
+        Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as? String ?? "development"
+    }
+}
+
+private enum UpdateCheckError: LocalizedError {
+    case invalidResponse(source: String)
+    case responseTooLarge(source: String)
+    case invalidRelease
+    case invalidVersion
+    case allSourcesUnavailable(web: String, api: String)
+
+    var errorDescription: String? {
+        switch self {
+        case let .invalidResponse(source):
+            "\(source) returned an unexpected response."
+        case let .responseTooLarge(source):
+            "\(source) response exceeded the accepted size."
+        case .invalidRelease:
+            "GitHub Release metadata did not match the official MHToolkit repository."
+        case .invalidVersion:
+            "The current or latest release version could not be compared safely."
+        case let .allSourcesUnavailable(web, api):
+            "GitHub release page/feed and API were unavailable. Web: \(web) API: \(api)"
+        }
+    }
+}
diff --git a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/Resources/Localizable.xcstrings b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/Resources/Localizable.xcstrings
index 1a06981..f9d4da8 100644
--- a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/Resources/Localizable.xcstrings
+++ b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/Resources/Localizable.xcstrings
@@ -54,6 +54,20 @@
     "Write.StagingSetSHA256" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Staging set SHA-256" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "暂存集合 SHA-256" } } } },
     "Write.TargetSetSHA256" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Target set SHA-256" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "目标集合 SHA-256" } } } },
     "Write.TargetSHA256" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Target SHA-256" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "目标文件 SHA-256" } } } },
+    "Update.About" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "About & Updates" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "关于与更新" } } } },
+    "Update.CurrentVersion" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Current version" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "当前版本" } } } },
+    "Update.Check" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Check for Updates" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "检查更新" } } } },
+    "Update.Checking" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Contacting GitHub…" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "正在连接 GitHub…" } } } },
+    "Update.UpToDate" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "You are up to date (GitHub: %@)" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "已经是最新版（GitHub：%@）" } } } },
+    "Update.Available" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Version %@ is available. Review its release notes in the update window." } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "发现新版本 %@，请在弹窗中查看更新说明。" } } } },
+    "Update.Failed" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Unable to check for updates" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "无法检查更新" } } } },
+    "Update.NetworkNote" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "The first launch each day silently checks GitHub Releases once. An unavailable network never blocks or changes any local save operation, and you can retry manually at any time." } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "每天首次启动会静默检查一次 GitHub Release；网络不可用时不会阻塞或影响任何本地存档操作。也可以随时手动重试。" } } } },
+    "Update.AvailableTitle" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Update Available" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "发现新版本" } } } },
+    "Update.VersionSummary" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Current %@ · Latest %@" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "当前 %@ · 最新 %@" } } } },
+    "Update.ReleaseNotes" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Release notes" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "更新说明" } } } },
+    "Update.NoReleaseNotes" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "No release notes were provided for this version." } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "该版本未提供更新说明。" } } } },
+    "Update.Later" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Later" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "稍后" } } } },
+    "Update.OpenRelease" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Open Release Page" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "打开发布页面" } } } },
     "WorkflowState.ComponentSelection" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Inspection complete" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "已完成检查" } } } },
     "WorkflowState.DryRun" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Dry Run complete" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "Dry Run 已完成" } } } },
     "WorkflowState.Failure" : { "localizations" : { "en" : { "stringUnit" : { "state" : "translated", "value" : "Operation failed" } }, "zh-Hans" : { "stringUnit" : { "state" : "translated", "value" : "操作失败" } } } },
diff --git a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/SettingsView.swift b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/SettingsView.swift
index c98b395..96c145a 100644
--- a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/SettingsView.swift
+++ b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/SettingsView.swift
@@ -4,6 +4,7 @@ import ConverterPresentation
 struct SettingsView: View {
     @Binding var localeOverride: String
     @Bindable var workflow: ConversionWorkflow
+    @ObservedObject var updateChecker: GitHubUpdateChecker
     let language: ConverterLanguage
 
     var body: some View {
@@ -37,8 +38,65 @@ struct SettingsView: View {
                         value: ConverterCopy.text(workflow.state.localizationKey, language: language)
                     )
                 }
+
+                Section(ConverterCopy.text("Update.About", language: language)) {
+                    LabeledContent(ConverterCopy.text("Update.CurrentVersion", language: language)) {
+                        Text(updateChecker.currentVersion)
+                            .font(.caption.monospaced())
+                    }
+
+                    HStack(spacing: 10) {
+                        Button(ConverterCopy.text("Update.Check", language: language)) {
+                            Task { await updateChecker.checkManually() }
+                        }
+                        .disabled(updateChecker.isChecking)
+
+                        if updateChecker.isChecking {
+                            ProgressView()
+                                .controlSize(.small)
+                            Text(ConverterCopy.text("Update.Checking", language: language))
+                                .font(.caption)
+                                .foregroundStyle(.secondary)
+                        }
+                    }
+
+                    updateStatus
+
+                    Text(ConverterCopy.text("Update.NetworkNote", language: language))
+                        .font(.caption)
+                        .foregroundStyle(.secondary)
+                }
             }
             .formStyle(.grouped)
         }
     }
+
+    @ViewBuilder
+    private var updateStatus: some View {
+        switch updateChecker.status {
+        case .idle, .checking:
+            EmptyView()
+        case let .upToDate(latest):
+            Label(
+                String(format: ConverterCopy.text("Update.UpToDate", language: language), latest),
+                systemImage: "checkmark.circle.fill"
+            )
+            .foregroundStyle(.green)
+        case let .updateAvailable(latest):
+            Label(
+                String(format: ConverterCopy.text("Update.Available", language: language), latest),
+                systemImage: "arrow.down.circle.fill"
+            )
+            .foregroundStyle(.tint)
+        case let .failed(detail):
+            VStack(alignment: .leading, spacing: 4) {
+                Label(ConverterCopy.text("Update.Failed", language: language), systemImage: "wifi.exclamationmark")
+                    .foregroundStyle(.orange)
+                Text(detail)
+                    .font(.caption.monospaced())
+                    .foregroundStyle(.secondary)
+                    .textSelection(.enabled)
+            }
+        }
+    }
 }
diff --git a/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/UpdateReleaseView.swift b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/UpdateReleaseView.swift
new file mode 100644
index 0000000..e65439a
--- /dev/null
+++ b/apps/mh3g-save-converter-macos/Sources/MH3GSaveConverterMac/UpdateReleaseView.swift
@@ -0,0 +1,94 @@
+import AppKit
+import ConverterPresentation
+import SwiftUI
+
+struct UpdateReleaseView: View {
+    let release: GitHubConverterRelease
+    let currentVersion: String
+    let language: ConverterLanguage
+
+    @Environment(\.dismiss) private var dismiss
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 18) {
+            HStack(alignment: .top, spacing: 14) {
+                Image(systemName: "arrow.down.circle.fill")
+                    .font(.system(size: 34))
+                    .foregroundStyle(.tint)
+                    .accessibilityHidden(true)
+                VStack(alignment: .leading, spacing: 4) {
+                    Text(ConverterCopy.text("Update.AvailableTitle", language: language))
+                        .font(.title2.weight(.semibold))
+                    Text(releaseTitle)
+                        .font(.headline)
+                    Text(
+                        String(
+                            format: ConverterCopy.text("Update.VersionSummary", language: language),
+                            currentVersion,
+                            release.tagName
+                        )
+                    )
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                    if let published = formattedPublishedDate {
+                        Text(published)
+                            .font(.caption)
+                            .foregroundStyle(.secondary)
+                    }
+                }
+            }
+
+            Divider()
+
+            Text(ConverterCopy.text("Update.ReleaseNotes", language: language))
+                .font(.headline)
+            ScrollView {
+                Text(releaseNotes)
+                    .frame(maxWidth: .infinity, alignment: .leading)
+                    .textSelection(.enabled)
+            }
+            .frame(minHeight: 150, maxHeight: 320)
+
+            HStack {
+                Spacer()
+                Button(ConverterCopy.text("Update.Later", language: language)) {
+                    dismiss()
+                }
+                Button(ConverterCopy.text("Update.OpenRelease", language: language)) {
+                    NSWorkspace.shared.open(release.htmlURL)
+                    dismiss()
+                }
+                .keyboardShortcut(.defaultAction)
+            }
+        }
+        .padding(24)
+        .frame(minWidth: 540, idealWidth: 600, minHeight: 390)
+    }
+
+    private var formattedPublishedDate: String? {
+        guard let value = release.publishedAt,
+              let date = ISO8601DateFormatter().date(from: value)
+        else {
+            return nil
+        }
+        return date.formatted(date: .long, time: .omitted)
+    }
+
+    private var releaseTitle: String {
+        guard let name = release.name?.trimmingCharacters(in: .whitespacesAndNewlines),
+              !name.isEmpty
+        else {
+            return release.tagName
+        }
+        return name
+    }
+
+    private var releaseNotes: String {
+        guard let body = release.body?.trimmingCharacters(in: .whitespacesAndNewlines),
+              !body.isEmpty
+        else {
+            return ConverterCopy.text("Update.NoReleaseNotes", language: language)
+        }
+        return body
+    }
+}
diff --git a/apps/mh3g-save-converter-macos/Tests/ConverterPresentationTests/UpdateCheckingTests.swift b/apps/mh3g-save-converter-macos/Tests/ConverterPresentationTests/UpdateCheckingTests.swift
new file mode 100644
index 0000000..92a7504
--- /dev/null
+++ b/apps/mh3g-save-converter-macos/Tests/ConverterPresentationTests/UpdateCheckingTests.swift
@@ -0,0 +1,114 @@
+import Foundation
+import XCTest
+@testable import ConverterPresentation
+
+final class UpdateCheckingTests: XCTestCase {
+    func testSemanticVersionAcceptsReleaseTagsAndComparesNumerically() throws {
+        let current = try XCTUnwrap(ConverterSemanticVersion("0.0.16"))
+        let latest = try XCTUnwrap(ConverterSemanticVersion("v0.0.17"))
+        let twoDigit = try XCTUnwrap(ConverterSemanticVersion("0.0.100"))
+
+        XCTAssertLessThan(current, latest)
+        XCTAssertLessThan(latest, twoDigit)
+        XCTAssertEqual(ConverterSemanticVersion("1.2"), ConverterSemanticVersion("1.2.0"))
+    }
+
+    func testMalformedVersionsFailClosed() {
+        XCTAssertNil(ConverterSemanticVersion("release-latest"))
+        XCTAssertNil(ConverterSemanticVersion("1..2"))
+        XCTAssertEqual(
+            ConverterUpdateDecision.decide(current: "development", latest: "v0.0.17"),
+            .invalidVersion
+        )
+    }
+
+    func testGitHubReleasePayloadDecodesExpectedFields() throws {
+        let payload = #"{"tag_name":"v0.0.17","name":"MH3G 0.0.17","body":"Fix notes","html_url":"https://github.com/MHToolkit/mh-save-sync/releases/tag/v0.0.17","published_at":"2026-08-10T00:00:00Z","draft":false,"prerelease":false}"#.data(using: .utf8)!
+        let release = try JSONDecoder().decode(GitHubConverterRelease.self, from: payload)
+
+        XCTAssertEqual(release.tagName, "v0.0.17")
+        XCTAssertEqual(release.name, "MH3G 0.0.17")
+        XCTAssertEqual(release.body, "Fix notes")
+        XCTAssertFalse(release.draft)
+        XCTAssertFalse(release.prerelease)
+        XCTAssertTrue(release.isOfficialStableRelease)
+    }
+
+    func testReleaseLinkMustBelongToTheOfficialRepository() throws {
+        let spoofed = GitHubConverterRelease(
+            tagName: "v9.9.9",
+            name: nil,
+            body: nil,
+            htmlURL: try XCTUnwrap(URL(string: "https://github.com.evil.example/MHToolkit/mh-save-sync/releases/tag/v9.9.9")),
+            publishedAt: nil,
+            draft: false,
+            prerelease: false
+        )
+
+        XCTAssertFalse(spoofed.isOfficialStableRelease)
+    }
+
+    func testAtomFeedConvertsTheExpectedStableReleaseAndPlainTextNotes() throws {
+        let feed = #"""
+        <?xml version="1.0" encoding="UTF-8"?>
+        <feed xmlns="http://www.w3.org/2005/Atom">
+          <entry>
+            <updated>2026-08-10T00:00:00Z</updated>
+            <link rel="alternate" type="text/html" href="https://github.com/MHToolkit/mh-save-sync/releases/tag/v0.0.17"/>
+            <title>MH3G 0.0.17</title>
+            <content type="html">&lt;h2&gt;Fixes&lt;/h2&gt;&lt;ul&gt;&lt;li&gt;Rate-limit fallback&lt;/li&gt;&lt;/ul&gt;</content>
+          </entry>
+        </feed>
+        """#.data(using: .utf8)!
+        let expectedURL = try XCTUnwrap(
+            URL(string: "https://github.com/MHToolkit/mh-save-sync/releases/tag/v0.0.17")
+        )
+
+        let release = try GitHubReleaseAtomFeed.stableRelease(
+            from: feed,
+            expectedReleaseURL: expectedURL
+        )
+
+        XCTAssertEqual(release.tagName, "v0.0.17")
+        XCTAssertEqual(release.name, "MH3G 0.0.17")
+        XCTAssertEqual(release.body, "Fixes\n• Rate-limit fallback")
+        XCTAssertEqual(release.publishedAt, "2026-08-10T00:00:00Z")
+        XCTAssertTrue(release.isOfficialStableRelease)
+    }
+
+    func testAtomFeedRequiresTheExactOfficialTagURLAndMatchingEntry() throws {
+        let feed = #"""
+        <feed xmlns="http://www.w3.org/2005/Atom">
+          <entry>
+            <link rel="alternate" href="https://github.com/MHToolkit/mh-save-sync/releases/tag/v0.0.17"/>
+            <title>v0.0.17</title>
+          </entry>
+        </feed>
+        """#.data(using: .utf8)!
+        let spoofed = try XCTUnwrap(
+            URL(string: "https://github.com.evil.example/MHToolkit/mh-save-sync/releases/tag/v0.0.17")
+        )
+        let missing = try XCTUnwrap(
+            URL(string: "https://github.com/MHToolkit/mh-save-sync/releases/tag/v0.0.18")
+        )
+
+        XCTAssertThrowsError(
+            try GitHubReleaseAtomFeed.stableRelease(from: feed, expectedReleaseURL: spoofed)
+        )
+        XCTAssertThrowsError(
+            try GitHubReleaseAtomFeed.stableRelease(from: feed, expectedReleaseURL: missing)
+        )
+    }
+
+    func testDailyGateRunsOnlyOncePerLocalCalendarDay() throws {
+        var calendar = Calendar(identifier: .gregorian)
+        calendar.timeZone = try XCTUnwrap(TimeZone(secondsFromGMT: 8 * 3600))
+        let lastAttempt = try XCTUnwrap(calendar.date(from: DateComponents(year: 2026, month: 8, day: 10, hour: 1)))
+        let sameDay = try XCTUnwrap(calendar.date(from: DateComponents(year: 2026, month: 8, day: 10, hour: 23)))
+        let nextDay = try XCTUnwrap(calendar.date(from: DateComponents(year: 2026, month: 8, day: 11, hour: 0)))
+
+        XCTAssertFalse(DailyUpdateCheckGate.shouldCheck(lastAttempt: lastAttempt, now: sameDay, calendar: calendar))
+        XCTAssertTrue(DailyUpdateCheckGate.shouldCheck(lastAttempt: lastAttempt, now: nextDay, calendar: calendar))
+        XCTAssertTrue(DailyUpdateCheckGate.shouldCheck(lastAttempt: nil, now: sameDay, calendar: calendar))
+    }
+}
diff --git a/apps/mh3g-save-converter-windows/Infrastructure/ConverterCopy.cs b/apps/mh3g-save-converter-windows/Infrastructure/ConverterCopy.cs
index 5b40212..3dd3a32 100644
--- a/apps/mh3g-save-converter-windows/Infrastructure/ConverterCopy.cs
+++ b/apps/mh3g-save-converter-windows/Infrastructure/ConverterCopy.cs
@@ -32,6 +32,21 @@ public void SetLanguage(AppLanguageOverride language)
     public string LanguageSystem => Text(nameof(LanguageSystem));
     public string LanguageChinese => Text(nameof(LanguageChinese));
     public string LanguageEnglish => Text(nameof(LanguageEnglish));
+    public string AboutUpdates => Text(nameof(AboutUpdates));
+    public string AboutDescription => Text(nameof(AboutDescription));
+    public string CurrentVersion => Text(nameof(CurrentVersion));
+    public string CheckForUpdates => Text(nameof(CheckForUpdates));
+    public string CheckingForUpdates => Text(nameof(CheckingForUpdates));
+    public string UpdateAvailableTitle => Text(nameof(UpdateAvailableTitle));
+    public string UpdateAvailableSummary => Text(nameof(UpdateAvailableSummary));
+    public string ReleaseNotes => Text(nameof(ReleaseNotes));
+    public string NoReleaseNotes => Text(nameof(NoReleaseNotes));
+    public string OpenReleasePage => Text(nameof(OpenReleasePage));
+    public string UpToDateTitle => Text(nameof(UpToDateTitle));
+    public string UpToDateMessage => Text(nameof(UpToDateMessage));
+    public string UpdateCheckFailed => Text(nameof(UpdateCheckFailed));
+    public string UpdateNetworkNote => Text(nameof(UpdateNetworkNote));
+    public string Close => Text(nameof(Close));
     public string StageInput => Text(nameof(StageInput));
     public string StageInspect => Text(nameof(StageInspect));
     public string StageDryRun => Text(nameof(StageDryRun));
@@ -183,6 +198,21 @@ private string Text(string key)
         [nameof(LanguageSystem)] = "System default",
         [nameof(LanguageChinese)] = "Simplified Chinese",
         [nameof(LanguageEnglish)] = "English",
+        [nameof(AboutUpdates)] = "About & Updates",
+        [nameof(AboutDescription)] = "MH3G Save Converter uses the bundled local Rust converter. Update checks read only the official MHToolkit GitHub Release metadata.",
+        [nameof(CurrentVersion)] = "Current version",
+        [nameof(CheckForUpdates)] = "Check for Updates",
+        [nameof(CheckingForUpdates)] = "Contacting GitHub…",
+        [nameof(UpdateAvailableTitle)] = "Update Available",
+        [nameof(UpdateAvailableSummary)] = "Current {0} · Latest {1}",
+        [nameof(ReleaseNotes)] = "Release notes",
+        [nameof(NoReleaseNotes)] = "No release notes were provided for this version.",
+        [nameof(OpenReleasePage)] = "Open Release Page",
+        [nameof(UpToDateTitle)] = "Up to date",
+        [nameof(UpToDateMessage)] = "Version {0} is the latest published release.",
+        [nameof(UpdateCheckFailed)] = "Unable to check for updates",
+        [nameof(UpdateNetworkNote)] = "The first launch each day checks GitHub Releases once. A blocked or unavailable network never blocks or changes local save operations; use this button to retry manually.",
+        [nameof(Close)] = "Close",
         [nameof(StageInput)] = "Input",
         [nameof(StageInspect)] = "Inspect",
         [nameof(StageDryRun)] = "Dry Run",
@@ -336,6 +366,21 @@ private string Text(string key)
         [nameof(LanguageSystem)] = "跟随系统",
         [nameof(LanguageChinese)] = "简体中文",
         [nameof(LanguageEnglish)] = "English",
+        [nameof(AboutUpdates)] = "关于与更新",
+        [nameof(AboutDescription)] = "MH3G Save Converter 使用内置的本地 Rust 转换器。更新检查只读取 MHToolkit 官方 GitHub Release 元数据。",
+        [nameof(CurrentVersion)] = "当前版本",
+        [nameof(CheckForUpdates)] = "检查更新",
+        [nameof(CheckingForUpdates)] = "正在连接 GitHub…",
+        [nameof(UpdateAvailableTitle)] = "发现新版本",
+        [nameof(UpdateAvailableSummary)] = "当前 {0} · 最新 {1}",
+        [nameof(ReleaseNotes)] = "更新说明",
+        [nameof(NoReleaseNotes)] = "该版本未提供更新说明。",
+        [nameof(OpenReleasePage)] = "打开发布页面",
+        [nameof(UpToDateTitle)] = "已经是最新版",
+        [nameof(UpToDateMessage)] = "版本 {0} 是当前最新正式版。",
+        [nameof(UpdateCheckFailed)] = "无法检查更新",
+        [nameof(UpdateNetworkNote)] = "每天首次启动会检查一次 GitHub Release；网络受限或不可用时不会阻塞或改动任何本地存档，也可以在这里手动重试。",
+        [nameof(Close)] = "关闭",
         [nameof(StageInput)] = "输入",
         [nameof(StageInspect)] = "检查",
         [nameof(StageDryRun)] = "Dry Run",
diff --git a/apps/mh3g-save-converter-windows/MainWindow.xaml b/apps/mh3g-save-converter-windows/MainWindow.xaml
index 50ca378..a3ab643 100644
--- a/apps/mh3g-save-converter-windows/MainWindow.xaml
+++ b/apps/mh3g-save-converter-windows/MainWindow.xaml
@@ -6,7 +6,7 @@
     xmlns:converter="using:MHToolkit.MH3GSaveConverter.Windows.Controls"
     xmlns:models="using:MHToolkit.MH3GSaveConverter.Windows.Models"
     Title="MH3G Save Converter">
-    <Grid x:Name="RootGrid" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
+    <Grid x:Name="RootGrid" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" Loaded="RootGrid_Loaded">
         <Grid.RowDefinitions>
             <RowDefinition Height="Auto" />
             <RowDefinition Height="*" />
@@ -34,6 +34,12 @@
                                    AutomationProperties.LiveSetting="Polite"
                                    AutomationProperties.Name="{Binding StatusText}" />
                     </Border>
+                    <Button Click="About_Click" Style="{StaticResource QuietButtonStyle}" ToolTipService.ToolTip="{Binding Copy.AboutUpdates}">
+                        <StackPanel Orientation="Horizontal" Spacing="7">
+                            <SymbolIcon Symbol="Help" />
+                            <TextBlock Text="{Binding Copy.AboutUpdates}" />
+                        </StackPanel>
+                    </Button>
                     <TextBlock Text="{Binding Copy.Language}" VerticalAlignment="Center" Foreground="{StaticResource ConverterSlateBrush}" />
                     <ComboBox x:Name="LanguagePicker" MinWidth="150" SelectionChanged="LanguagePicker_SelectionChanged">
                         <ComboBoxItem Tag="system" Content="{Binding Copy.LanguageSystem}" />
diff --git a/apps/mh3g-save-converter-windows/MainWindow.xaml.cs b/apps/mh3g-save-converter-windows/MainWindow.xaml.cs
index 35ecb43..93b1f70 100644
--- a/apps/mh3g-save-converter-windows/MainWindow.xaml.cs
+++ b/apps/mh3g-save-converter-windows/MainWindow.xaml.cs
@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using Microsoft.UI.Composition.SystemBackdrops;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
@@ -5,15 +6,22 @@
 using Windows.Graphics;
 using Windows.Storage.Pickers;
 using WinRT.Interop;
+using MHToolkit.MH3GSaveConverter.Windows.Models;
+using MHToolkit.MH3GSaveConverter.Windows.Services;
 using MHToolkit.MH3GSaveConverter.Windows.ViewModels;
 
 namespace MHToolkit.MH3GSaveConverter.Windows;
 
 public sealed partial class MainWindow : Window
 {
+    private readonly GitHubUpdateService _updateService = new();
+    private readonly UpdateCheckPreferenceStore _updateCheckStore = new();
+    private readonly SemaphoreSlim _dialogGate = new(1, 1);
+    private Task<UpdateCheckResult>? _activeUpdateCheck;
     private bool _synchronizingLanguage;
     private bool _synchronizingConversionMode;
     private bool _synchronizingRepairVersion;
+    private bool _loadedOnce;
 
     public MainWindow()
     {
@@ -28,6 +36,174 @@ public MainWindow()
 
     public MainViewModel ViewModel { get; }
 
+    private async void RootGrid_Loaded(object sender, RoutedEventArgs e)
+    {
+        if (_loadedOnce)
+        {
+            return;
+        }
+        _loadedOnce = true;
+
+        if (!_updateCheckStore.ShouldCheckToday())
+        {
+            return;
+        }
+
+        // Record the attempt before networking so a blocked GitHub connection
+        // is not retried on every launch during the same local calendar day.
+        _updateCheckStore.MarkAttempt();
+        await CheckForUpdatesAsync(manual: false);
+    }
+
+    private async void About_Click(object sender, RoutedEventArgs e)
+    {
+        var content = new StackPanel { Spacing = 10, Width = 520 };
+        content.Children.Add(new TextBlock
+        {
+            Text = ViewModel.Copy.AboutDescription,
+            TextWrapping = TextWrapping.Wrap,
+        });
+        content.Children.Add(new TextBlock
+        {
+            Text = $"{ViewModel.Copy.CurrentVersion}: {_updateService.CurrentVersion}",
+            FontFamily = new FontFamily("Cascadia Mono"),
+        });
+        content.Children.Add(new TextBlock
+        {
+            Text = ViewModel.Copy.UpdateNetworkNote,
+            TextWrapping = TextWrapping.Wrap,
+            Foreground = (Brush)Application.Current.Resources["ConverterSlateBrush"],
+        });
+
+        var dialog = new ContentDialog
+        {
+            Title = ViewModel.Copy.AboutUpdates,
+            Content = content,
+            PrimaryButtonText = ViewModel.Copy.CheckForUpdates,
+            CloseButtonText = ViewModel.Copy.Close,
+            DefaultButton = ContentDialogButton.Primary,
+        };
+        if (await ShowDialogAsync(dialog) == ContentDialogResult.Primary)
+        {
+            await CheckForUpdatesAsync(manual: true);
+        }
+    }
+
+    private async Task CheckForUpdatesAsync(bool manual)
+    {
+        try
+        {
+            var activeCheck = _activeUpdateCheck;
+            if (activeCheck is null || activeCheck.IsCompleted)
+            {
+                activeCheck = _updateService.CheckAsync();
+                _activeUpdateCheck = activeCheck;
+            }
+            var result = await activeCheck;
+            if (result.IsUpdateAvailable)
+            {
+                await ShowUpdateAvailableAsync(result);
+            }
+            else if (manual)
+            {
+                await ShowMessageAsync(
+                    ViewModel.Copy.UpToDateTitle,
+                    string.Format(ViewModel.Copy.UpToDateMessage, result.Release.TagName));
+            }
+        }
+        catch (Exception exception)
+        {
+            // Automatic checks are advisory and silent. They never delay the
+            // local workflow beyond their own timeout or surface a startup
+            // blocker when GitHub is unavailable in the user's network.
+            if (manual)
+            {
+                await ShowMessageAsync(
+                    ViewModel.Copy.UpdateCheckFailed,
+                    $"{ViewModel.Copy.UpdateNetworkNote}\n\n{exception.Message}");
+            }
+        }
+    }
+
+    private async Task ShowUpdateAvailableAsync(UpdateCheckResult result)
+    {
+        var release = result.Release;
+        var content = new StackPanel { Spacing = 10, Width = 560 };
+        content.Children.Add(new TextBlock
+        {
+            Text = string.Format(
+                ViewModel.Copy.UpdateAvailableSummary,
+                result.CurrentVersion,
+                release.TagName),
+            FontWeight = Microsoft.UI.Text.FontWeights.SemiBold,
+        });
+        if (release.PublishedAt is { } publishedAt)
+        {
+            content.Children.Add(new TextBlock
+            {
+                Text = publishedAt.ToLocalTime().ToString("D"),
+                Foreground = (Brush)Application.Current.Resources["ConverterSlateBrush"],
+            });
+        }
+        content.Children.Add(new TextBlock
+        {
+            Text = ViewModel.Copy.ReleaseNotes,
+            FontWeight = Microsoft.UI.Text.FontWeights.SemiBold,
+        });
+        content.Children.Add(new ScrollViewer
+        {
+            MaxHeight = 320,
+            VerticalScrollBarVisibility = ScrollBarVisibility.Auto,
+            Content = new TextBlock
+            {
+                Text = string.IsNullOrWhiteSpace(release.Body) ? ViewModel.Copy.NoReleaseNotes : release.Body,
+                TextWrapping = TextWrapping.Wrap,
+                IsTextSelectionEnabled = true,
+            },
+        });
+
+        var dialog = new ContentDialog
+        {
+            Title = string.IsNullOrWhiteSpace(release.Name)
+                ? ViewModel.Copy.UpdateAvailableTitle
+                : release.Name,
+            Content = content,
+            PrimaryButtonText = ViewModel.Copy.OpenReleasePage,
+            CloseButtonText = ViewModel.Copy.Close,
+            DefaultButton = ContentDialogButton.Primary,
+        };
+        if (await ShowDialogAsync(dialog) == ContentDialogResult.Primary)
+        {
+            Process.Start(new ProcessStartInfo(release.HtmlUrl) { UseShellExecute = true });
+        }
+    }
+
+    private async Task ShowMessageAsync(string title, string message)
+    {
+        var dialog = new ContentDialog
+        {
+            Title = title,
+            Content = new TextBlock { Text = message, TextWrapping = TextWrapping.Wrap },
+            CloseButtonText = ViewModel.Copy.Close,
+            DefaultButton = ContentDialogButton.Close,
+        };
+        await ShowDialogAsync(dialog);
+    }
+
+    private async Task<ContentDialogResult> ShowDialogAsync(ContentDialog dialog)
+    {
+        await _dialogGate.WaitAsync();
+        try
+        {
+            dialog.XamlRoot = RootGrid.XamlRoot;
+            return await dialog.ShowAsync();
+        }
+        finally
+        {
+            _dialogGate.Release();
+        }
+    }
+
     private void ConfigureWindowMaterial()
     {
         AppWindow.Resize(new SizeInt32(1240, 900));
@@ -468,14 +644,13 @@ private async Task<bool> ConfirmAsync(string title, string message)
     {
         var dialog = new ContentDialog
         {
-            XamlRoot = RootGrid.XamlRoot,
             Title = title,
             Content = new TextBlock { Text = message, TextWrapping = TextWrapping.Wrap },
             PrimaryButtonText = ViewModel.Copy.Continue,
             CloseButtonText = ViewModel.Copy.Cancel,
             DefaultButton = ContentDialogButton.Close,
         };
-        return await dialog.ShowAsync() == ContentDialogResult.Primary;
+        return await ShowDialogAsync(dialog) == ContentDialogResult.Primary;
     }
 
     private async Task RunSafelyAsync(Func<Task> operation)
diff --git a/apps/mh3g-save-converter-windows/Models/UpdateModels.cs b/apps/mh3g-save-converter-windows/Models/UpdateModels.cs
new file mode 100644
index 0000000..2e3ac0f
--- /dev/null
+++ b/apps/mh3g-save-converter-windows/Models/UpdateModels.cs
@@ -0,0 +1,32 @@
+using System.Text.Json.Serialization;
+
+namespace MHToolkit.MH3GSaveConverter.Windows.Models;
+
+public sealed class GitHubReleaseInfo
+{
+    [JsonPropertyName("tag_name")]
+    public string TagName { get; init; } = string.Empty;
+
+    [JsonPropertyName("name")]
+    public string? Name { get; init; }
+
+    [JsonPropertyName("body")]
+    public string? Body { get; init; }
+
+    [JsonPropertyName("html_url")]
+    public string HtmlUrl { get; init; } = string.Empty;
+
+    [JsonPropertyName("published_at")]
+    public DateTimeOffset? PublishedAt { get; init; }
+
+    [JsonPropertyName("draft")]
+    public bool Draft { get; init; }
+
+    [JsonPropertyName("prerelease")]
+    public bool Prerelease { get; init; }
+}
+
+public sealed record UpdateCheckResult(
+    string CurrentVersion,
+    GitHubReleaseInfo Release,
+    bool IsUpdateAvailable);
diff --git a/apps/mh3g-save-converter-windows/README.md b/apps/mh3g-save-converter-windows/README.md
index e70ed71..ccd89ca 100644
--- a/apps/mh3g-save-converter-windows/README.md
+++ b/apps/mh3g-save-converter-windows/README.md
@@ -30,7 +30,10 @@ code.
   Dry Run's aggregate source_record_set_sha256 and target_sha256_before are
   bound to its write, so a changed mailbox or cache fails closed. It never turns
   on merely because a player selected the primary slot.
-- `system` and normal ExtData staging/install remain explicit transactions.
+- Shared `system` and normal ExtData staging/install remain explicit
+  transactions. Gallery/movie migration requires both the 3DS source `system`
+  and an existing initialized Cemu `system`; only the known flags are unioned,
+  while all other target bytes and other-slot shared data are retained.
   The Windows backend installs complete ExtData groups through `ReplaceFileW`,
   manifest-bound backups, and a durable recovery journal. The UI never guesses
   a Cemu MLC directory or silently installs a group. Compatibility repair
@@ -42,6 +45,21 @@ Quit Nemessix, Azahar, and Cemu before any write or rollback. See the root
 [Chinese CLI contract](../../docs/MH3G_3DS_TO_CEMU_FILE_CONTRACT.zh-CN.md) for
 the exact source files and transaction scope.
 
+## Updates
+
+The About & Updates dialog resolves the latest stable tag through the official
+`MHToolkit/mh-save-sync` GitHub release page and reads its official Atom release
+feed. This path does not consume the shared anonymous GitHub API quota; the
+Release API remains a fallback. The first launch on each local calendar day
+makes at most one silent attempt. A blocked or unavailable GitHub connection
+never blocks the window or changes a local save; manual checks display the
+failure and can be retried. A newer release dialog includes the release title,
+publication date, notes, and official link.
+
+The package script passes the Rust converter version into both WinUI publish
+forms, so the folder, portable EXE, and installer compare the same real version
+instead of the .NET default assembly version.
+
 ## Release formats
 
 The one-command package build produces three Windows x64 formats from the same
diff --git a/apps/mh3g-save-converter-windows/README.zh-CN.md b/apps/mh3g-save-converter-windows/README.zh-CN.md
index 7a5a34f..71f08f2 100644
--- a/apps/mh3g-save-converter-windows/README.zh-CN.md
+++ b/apps/mh3g-save-converter-windows/README.zh-CN.md
@@ -26,7 +26,9 @@
   回滚链路。写入会绑定紧接着的 Dry Run 返回的聚合
   source_record_set_sha256 与 target_sha256_before，邮箱或缓存变化时会
   失败关闭。选择核心槽位不会自动打开 CEC。
-- `system` 与普通 ExtData 暂存/安装仍是显式事务。Windows 后端使用
+- 共享 `system` 与普通 ExtData 暂存/安装仍是显式事务。画廊/动画迁移必须同时
+  提供 3DS 源 `system` 和已存在、已初始化的 Cemu `system`；只合并已知标记，
+  其余目标字节和其他角色槽位共享数据全部保留。Windows 后端使用
   `ReplaceFileW`、manifest 绑定备份和持久恢复日志安装完整 ExtData 组件组；
   界面不会猜测 Cemu MLC 目录或静默安装。兼容修复模式只字段级更新仍保持旧版
   转换结果的 `user#` 与公会名片字段，当前 `quest1` 至 `quest4` 保持原字节。
@@ -36,6 +38,17 @@
 [中文 CLI 文件契约](../../docs/MH3G_3DS_TO_CEMU_FILE_CONTRACT.zh-CN.md) 与
 [English CLI contract](../../docs/MH3G_3DS_TO_CEMU_FILE_CONTRACT.md)。
 
+## 更新检查
+
+“关于与更新”会通过 `MHToolkit/mh-save-sync` 官方 GitHub Release 页面确认最新
+正式版 tag，并读取官方 Atom Release feed。该主路径不消耗共享的 GitHub 匿名
+API 配额，Release API 仅作为备用。每个本地自然日首次启动最多静默尝试一次；
+GitHub 无法访问时不会阻塞窗口或改动本地存档，手动检查会展示失败信息并允许
+重试。发现新版本时，弹窗会显示版本名、发布日期、更新说明与官方链接。
+
+打包脚本会把 Rust 转换器版本同时注入 WinUI 文件夹版和单文件便携版，因此 ZIP、
+便携 EXE 和安装器比较的是同一个真实版本，不会误用 .NET 默认程序集版本。
+
 ## 发布格式
 
 一键打包会使用同一份原生 WinUI 应用与 Rust sidecar 生成三种 Windows x64 形式：
diff --git a/apps/mh3g-save-converter-windows/Services/GitHubUpdateService.cs b/apps/mh3g-save-converter-windows/Services/GitHubUpdateService.cs
new file mode 100644
index 0000000..9369b4f
--- /dev/null
+++ b/apps/mh3g-save-converter-windows/Services/GitHubUpdateService.cs
@@ -0,0 +1,285 @@
+using System.Globalization;
+using System.Net;
+using System.Net.Http.Headers;
+using System.Reflection;
+using System.Text.RegularExpressions;
+using System.Text.Json;
+using System.Xml;
+using System.Xml.Linq;
+using MHToolkit.MH3GSaveConverter.Windows.Models;
+
+namespace MHToolkit.MH3GSaveConverter.Windows.Services;
+
+public sealed class GitHubUpdateService
+{
+    private static readonly Uri LatestReleaseEndpoint = new(
+        "https://api.github.com/repos/MHToolkit/mh-save-sync/releases/latest");
+    private static readonly Uri LatestReleaseWebEndpoint = new(
+        "https://github.com/MHToolkit/mh-save-sync/releases/latest");
+    private static readonly Uri ReleaseAtomEndpoint = new(
+        "https://github.com/MHToolkit/mh-save-sync/releases.atom");
+
+    private readonly HttpClient _httpClient;
+
+    public GitHubUpdateService(HttpClient? httpClient = null, string? currentVersion = null)
+    {
+        _httpClient = httpClient ?? new HttpClient { Timeout = TimeSpan.FromSeconds(8) };
+        CurrentVersion = currentVersion ?? ResolveCurrentVersion();
+    }
+
+    public string CurrentVersion { get; }
+
+    public async Task<UpdateCheckResult> CheckAsync(CancellationToken cancellationToken = default)
+    {
+        GitHubReleaseInfo release;
+        try
+        {
+            release = await FetchFromWebFeedAsync(cancellationToken).ConfigureAwait(false);
+        }
+        catch (Exception webFailure) when (!cancellationToken.IsCancellationRequested)
+        {
+            try
+            {
+                release = await FetchFromApiAsync(cancellationToken).ConfigureAwait(false);
+            }
+            catch (Exception apiFailure) when (!cancellationToken.IsCancellationRequested)
+            {
+                throw new InvalidDataException(
+                    $"GitHub release page/feed and Release API were unavailable. Web: {webFailure.Message} API: {apiFailure.Message}",
+                    new AggregateException(webFailure, apiFailure));
+            }
+        }
+
+        return CreateResult(release);
+    }
+
+    private async Task<GitHubReleaseInfo> FetchFromWebFeedAsync(CancellationToken cancellationToken)
+    {
+        using var latestRequest = CreateRequest(HttpMethod.Get, LatestReleaseWebEndpoint, "text/html");
+        // HttpClient follows GitHub's stable /releases/latest redirect. One
+        // byte is enough to retain the final tag URL without downloading the
+        // full HTML release page.
+        latestRequest.Headers.Range = new RangeHeaderValue(0, 0);
+        using var latestResponse = await _httpClient.SendAsync(
+            latestRequest,
+            HttpCompletionOption.ResponseHeadersRead,
+            cancellationToken).ConfigureAwait(false);
+
+        Uri? stableReleaseUri;
+        if (latestResponse.StatusCode is HttpStatusCode.MovedPermanently
+            or HttpStatusCode.Found
+            or HttpStatusCode.SeeOther
+            or HttpStatusCode.TemporaryRedirect
+            or HttpStatusCode.PermanentRedirect)
+        {
+            stableReleaseUri = latestResponse.Headers.Location is { } location
+                ? new Uri(LatestReleaseWebEndpoint, location)
+                : null;
+        }
+        else
+        {
+            latestResponse.EnsureSuccessStatusCode();
+            stableReleaseUri = latestResponse.RequestMessage?.RequestUri;
+        }
+
+        if (stableReleaseUri is null || !IsOfficialReleaseTagUri(stableReleaseUri))
+        {
+            throw new InvalidDataException("GitHub latest-release redirect did not resolve to the official repository tag.");
+        }
+
+        using var feedRequest = CreateRequest(HttpMethod.Get, ReleaseAtomEndpoint, "application/atom+xml");
+        using var feedResponse = await _httpClient.SendAsync(feedRequest, cancellationToken).ConfigureAwait(false);
+        feedResponse.EnsureSuccessStatusCode();
+        var payload = await ReadBoundedContentAsync(
+            feedResponse,
+            "GitHub release feed",
+            cancellationToken).ConfigureAwait(false);
+        return ParseAtomRelease(payload, stableReleaseUri);
+    }
+
+    private async Task<GitHubReleaseInfo> FetchFromApiAsync(CancellationToken cancellationToken)
+    {
+        using var request = CreateRequest(
+            HttpMethod.Get,
+            LatestReleaseEndpoint,
+            "application/vnd.github+json");
+        request.Headers.Add("X-GitHub-Api-Version", "2022-11-28");
+
+        using var response = await _httpClient.SendAsync(request, cancellationToken).ConfigureAwait(false);
+        response.EnsureSuccessStatusCode();
+        var payload = await ReadBoundedContentAsync(
+            response,
+            "GitHub Release API",
+            cancellationToken).ConfigureAwait(false);
+
+        var release = JsonSerializer.Deserialize<GitHubReleaseInfo>(payload)
+            ?? throw new InvalidDataException("GitHub Release API returned an empty payload.");
+        ValidateRelease(release);
+        return release;
+    }
+
+    private HttpRequestMessage CreateRequest(HttpMethod method, Uri endpoint, string accept)
+    {
+        var request = new HttpRequestMessage(method, endpoint);
+        request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue(accept));
+        request.Headers.UserAgent.ParseAdd($"MH3GSaveConverter/{SafeUserAgentVersion(CurrentVersion)}");
+        return request;
+    }
+
+    private static async Task<byte[]> ReadBoundedContentAsync(
+        HttpResponseMessage response,
+        string source,
+        CancellationToken cancellationToken)
+    {
+        if (response.Content.Headers.ContentLength is > 2 * 1024 * 1024)
+        {
+            throw new InvalidDataException($"{source} response exceeded the accepted size.");
+        }
+
+        var payload = await response.Content.ReadAsByteArrayAsync(cancellationToken).ConfigureAwait(false);
+        if (payload.Length > 2 * 1024 * 1024)
+        {
+            throw new InvalidDataException($"{source} response exceeded the accepted size.");
+        }
+        return payload;
+    }
+
+    private static GitHubReleaseInfo ParseAtomRelease(byte[] payload, Uri stableReleaseUri)
+    {
+        var settings = new XmlReaderSettings
+        {
+            DtdProcessing = DtdProcessing.Prohibit,
+            XmlResolver = null,
+            MaxCharactersInDocument = 2 * 1024 * 1024,
+        };
+        using var input = new MemoryStream(payload, writable: false);
+        using var reader = XmlReader.Create(input, settings);
+        var document = XDocument.Load(reader, LoadOptions.None);
+        XNamespace atom = "http://www.w3.org/2005/Atom";
+        var entry = document.Root?
+            .Elements(atom + "entry")
+            .FirstOrDefault(candidate =>
+            {
+                var href = candidate
+                    .Elements(atom + "link")
+                    .FirstOrDefault(link => string.Equals(
+                        (string?)link.Attribute("rel"),
+                        "alternate",
+                        StringComparison.Ordinal))?
+                    .Attribute("href")?
+                    .Value;
+                return Uri.TryCreate(href, UriKind.Absolute, out var entryUri)
+                    && string.Equals(
+                        entryUri.AbsoluteUri,
+                        stableReleaseUri.AbsoluteUri,
+                        StringComparison.Ordinal);
+            })
+            ?? throw new InvalidDataException("The stable GitHub release was not present in the official release feed.");
+
+        var tagName = Uri.UnescapeDataString(stableReleaseUri.Segments[^1]);
+        DateTimeOffset? publishedAt = null;
+        if (DateTimeOffset.TryParse(
+            entry.Element(atom + "updated")?.Value,
+            CultureInfo.InvariantCulture,
+            DateTimeStyles.AssumeUniversal | DateTimeStyles.AdjustToUniversal,
+            out var parsedPublishedAt))
+        {
+            publishedAt = parsedPublishedAt;
+        }
+
+        var release = new GitHubReleaseInfo
+        {
+            TagName = tagName,
+            Name = entry.Element(atom + "title")?.Value.Trim(),
+            Body = PlainTextFromHtml(entry.Element(atom + "content")?.Value ?? string.Empty),
+            HtmlUrl = stableReleaseUri.AbsoluteUri,
+            PublishedAt = publishedAt,
+            Draft = false,
+            Prerelease = false,
+        };
+        ValidateRelease(release);
+        return release;
+    }
+
+    private static string PlainTextFromHtml(string html)
+    {
+        var text = Regex.Replace(html, @"(?i)<li(?:\s[^>]*)?>", "• ");
+        text = Regex.Replace(
+            text,
+            @"(?i)<br\s*/?>|</li\s*>|</p\s*>|</h[1-6]\s*>|</blockquote\s*>|</pre\s*>",
+            "\n");
+        text = Regex.Replace(text, @"<[^>]+>", string.Empty);
+        text = WebUtility.HtmlDecode(text);
+        var normalized = string.Join(
+            Environment.NewLine,
+            text.Split('\n', StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries));
+        return normalized.Length <= 32_000 ? normalized : normalized[..32_000];
+    }
+
+    private UpdateCheckResult CreateResult(GitHubReleaseInfo release)
+    {
+        ValidateRelease(release);
+
+        if (!TryParseVersion(CurrentVersion, out var current)
+            || !TryParseVersion(release.TagName, out var latest))
+        {
+            throw new InvalidDataException("The current or latest release version could not be compared safely.");
+        }
+
+        return new UpdateCheckResult(CurrentVersion, release, latest > current);
+    }
+
+    private static bool IsOfficialReleaseTagUri(Uri releaseUri)
+    {
+        return releaseUri.Scheme.Equals(Uri.UriSchemeHttps, StringComparison.OrdinalIgnoreCase)
+            && releaseUri.Host.Equals("github.com", StringComparison.OrdinalIgnoreCase)
+            && string.IsNullOrEmpty(releaseUri.Query)
+            && string.IsNullOrEmpty(releaseUri.Fragment)
+            && releaseUri.AbsolutePath.StartsWith(
+                "/MHToolkit/mh-save-sync/releases/tag/",
+                StringComparison.Ordinal)
+            && releaseUri.Segments.Length == 6
+            && TryParseVersion(Uri.UnescapeDataString(releaseUri.Segments[^1]), out _);
+    }
+
+    internal static bool TryParseVersion(string value, out Version version)
+    {
+        var normalized = value.Trim().TrimStart('v', 'V').Split('+', 2)[0].Split('-', 2)[0];
+        if (Version.TryParse(normalized, out var parsed))
+        {
+            version = parsed;
+            return true;
+        }
+        version = new Version(0, 0);
+        return false;
+    }
+
+    private static void ValidateRelease(GitHubReleaseInfo release)
+    {
+        if (release.Draft
+            || release.Prerelease
+            || !Uri.TryCreate(release.HtmlUrl, UriKind.Absolute, out var releaseUri)
+            || !releaseUri.Scheme.Equals(Uri.UriSchemeHttps, StringComparison.OrdinalIgnoreCase)
+            || !releaseUri.Host.Equals("github.com", StringComparison.OrdinalIgnoreCase)
+            || !releaseUri.AbsolutePath.StartsWith("/MHToolkit/mh-save-sync/releases/", StringComparison.Ordinal))
+        {
+            throw new InvalidDataException("GitHub Release metadata did not match the official MHToolkit repository.");
+        }
+    }
+
+    private static string ResolveCurrentVersion()
+    {
+        var assembly = Assembly.GetEntryAssembly() ?? typeof(GitHubUpdateService).Assembly;
+        var informational = assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion;
+        if (!string.IsNullOrWhiteSpace(informational))
+        {
+            return informational.Split('+', 2)[0];
+        }
+        return assembly.GetName().Version?.ToString(3) ?? "development";
+    }
+
+    private static string SafeUserAgentVersion(string version)
+    {
+        return TryParseVersion(version, out var parsed) ? parsed.ToString() : "0.0.0";
+    }
+}
diff --git a/apps/mh3g-save-converter-windows/Services/UpdateCheckPreferenceStore.cs b/apps/mh3g-save-converter-windows/Services/UpdateCheckPreferenceStore.cs
new file mode 100644
index 0000000..93202b3
--- /dev/null
+++ b/apps/mh3g-save-converter-windows/Services/UpdateCheckPreferenceStore.cs
@@ -0,0 +1,102 @@
+using System.Globalization;
+using System.Text.Json;
+
+namespace MHToolkit.MH3GSaveConverter.Windows.Services;
+
+public sealed class UpdateCheckPreferenceStore
+{
+    private const string StateFileName = "update-check.json";
+    private readonly string _statePath;
+    private bool _attemptedInProcess;
+
+    public UpdateCheckPreferenceStore(string? settingsDirectory = null)
+    {
+        var directory = settingsDirectory
+            ?? Path.Combine(
+                Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+                "MHToolkit",
+                "MH3GSaveConverter");
+        _statePath = Path.Combine(directory, StateFileName);
+    }
+
+    public bool ShouldCheckToday(DateTimeOffset? now = null)
+    {
+        if (_attemptedInProcess)
+        {
+            return false;
+        }
+
+        var localDate = (now ?? DateTimeOffset.Now).LocalDateTime.Date;
+        try
+        {
+            if (!File.Exists(_statePath))
+            {
+                return true;
+            }
+            var stored = JsonSerializer.Deserialize<StoredState>(File.ReadAllText(_statePath));
+            return !DateTime.TryParseExact(
+                stored?.LastAttemptLocalDate,
+                "yyyy-MM-dd",
+                CultureInfo.InvariantCulture,
+                DateTimeStyles.None,
+                out var lastAttempt)
+                || lastAttempt.Date != localDate;
+        }
+        catch (IOException)
+        {
+            return true;
+        }
+        catch (UnauthorizedAccessException)
+        {
+            return true;
+        }
+        catch (JsonException)
+        {
+            return true;
+        }
+    }
+
+    public void MarkAttempt(DateTimeOffset? now = null)
+    {
+        _attemptedInProcess = true;
+        var directory = Path.GetDirectoryName(_statePath)!;
+        var temporaryPath = Path.Combine(directory, $".{StateFileName}.{Guid.NewGuid():N}.tmp");
+        try
+        {
+            Directory.CreateDirectory(directory);
+            var state = new StoredState
+            {
+                LastAttemptLocalDate = (now ?? DateTimeOffset.Now).LocalDateTime.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture),
+            };
+            File.WriteAllBytes(temporaryPath, JsonSerializer.SerializeToUtf8Bytes(state));
+            File.Move(temporaryPath, _statePath, overwrite: true);
+        }
+        catch (IOException)
+        {
+            // The in-process gate still prevents repeated launch checks. A
+            // read-only profile may retry on the next application launch.
+        }
+        catch (UnauthorizedAccessException)
+        {
+            // Update checks are advisory and never block the converter.
+        }
+        finally
+        {
+            try
+            {
+                File.Delete(temporaryPath);
+            }
+            catch (IOException)
+            {
+            }
+            catch (UnauthorizedAccessException)
+            {
+            }
+        }
+    }
+
+    private sealed class StoredState
+    {
+        public string? LastAttemptLocalDate { get; init; }
+    }
+}
diff --git a/scripts/package-mh3g-save-converter-windows.ps1 b/scripts/package-mh3g-save-converter-windows.ps1
index 94e0943..af8d1a7 100644
--- a/scripts/package-mh3g-save-converter-windows.ps1
+++ b/scripts/package-mh3g-save-converter-windows.ps1
@@ -882,7 +882,8 @@ function Publish-PortableExecutable {
         [Parameter(Mandatory = $true)][string]$ProjectPath,
         [Parameter(Mandatory = $true)][string]$NativeSidecar,
         [Parameter(Mandatory = $true)][string]$PortableStageDirectory,
-        [Parameter(Mandatory = $true)][string]$PortableOutput
+        [Parameter(Mandatory = $true)][string]$PortableOutput,
+        [Parameter(Mandatory = $true)][string]$Version
     )
 
     # The UI invokes the Rust converter from AppContext.BaseDirectory\tools.
@@ -908,7 +909,7 @@ function Publish-PortableExecutable {
         Invoke-External -FilePath $Dotnet -Arguments @(
             "publish", $ProjectPath, "-c", "Release", "-r", "win-x64", "--self-contained", "true", "--no-restore",
             "-p:Platform=x64", "-p:WindowsAppSDKSelfContained=true", "-p:PublishSingleFile=true",
-            "-p:IncludeAllContentForSelfExtract=true", "-p:PublishReadyToRun=false", "-o", $PortableStageDirectory
+            "-p:IncludeAllContentForSelfExtract=true", "-p:PublishReadyToRun=false", "-p:Version=$Version", "-o", $PortableStageDirectory
         ) -Description "WinUI portable single-file dotnet publish"
 
         $publishedPortable = Join-Path $PortableStageDirectory "MH3GSaveConverter.exe"
@@ -1173,6 +1174,7 @@ try {
         }
         Assert-NativeConverterSidecar -FilePath $sidecar
         Invoke-External -FilePath $sidecar -Arguments @("--help") -Description "release sidecar smoke"
+        $converterVersion = Get-ConverterVersion
 
         # Recheck directly before recursive deletion in case an existing stage
         # component was replaced by a junction/symlink after initial preflight.
@@ -1180,7 +1182,7 @@ try {
         Remove-Item -LiteralPath $stage -Recurse -Force -ErrorAction SilentlyContinue
         Invoke-External -FilePath $dotnet -Arguments @(
             "publish", $project, "-c", "Release", "-r", "win-x64", "--self-contained", "true", "--no-restore",
-            "-p:Platform=x64", "-p:WindowsAppSDKSelfContained=true", "-o", $stage
+            "-p:Platform=x64", "-p:WindowsAppSDKSelfContained=true", "-p:Version=$converterVersion", "-o", $stage
         ) -Description "WinUI dotnet publish"
 
         $gui = Join-Path $stage "MH3GSaveConverter.exe"
@@ -1212,10 +1214,9 @@ try {
         # that sidecar as extracted app content; the installer wraps the folder
         # form so its tools\ path remains intact.
         Remove-Item -LiteralPath $portableExecutable, $portableChecksum, $installerExecutable, $installerChecksum -Force -ErrorAction SilentlyContinue
-        Publish-PortableExecutable -Dotnet $dotnet -ProjectPath $project -NativeSidecar $sidecar -PortableStageDirectory $portableStage -PortableOutput $portableExecutable
+        Publish-PortableExecutable -Dotnet $dotnet -ProjectPath $project -NativeSidecar $sidecar -PortableStageDirectory $portableStage -PortableOutput $portableExecutable -Version $converterVersion
         Write-Sha256File -FilePath $portableExecutable -OutputPath $portableChecksum -DisplayName "MH3GSaveConverter-Portable-x64.exe" | Out-Null
 
-        $converterVersion = Get-ConverterVersion
         Build-InstallerExecutable -InstallerCompiler $innoSetup -InstallerDefinition $installerScript -SourceDirectory $stage -Version $converterVersion -InstallerOutput $installerExecutable
         Write-Sha256File -FilePath $installerExecutable -OutputPath $installerChecksum -DisplayName "MH3GSaveConverter-Setup-x64.exe" | Out-Null
 
diff --git a/scripts/verify-mh3g-save-converter-windows-source.py b/scripts/verify-mh3g-save-converter-windows-source.py
index f0402d4..7fd0a2c 100644
--- a/scripts/verify-mh3g-save-converter-windows-source.py
+++ b/scripts/verify-mh3g-save-converter-windows-source.py
@@ -147,6 +147,7 @@ def verify_local_packaging_script() -> None:
         "WindowsAppSDKSelfContained=true",
         "PublishSingleFile=true",
         "IncludeAllContentForSelfExtract=true",
+        "-p:Version=$converterVersion",
         "Publish-PortableExecutable",
         "Build-InstallerExecutable",
         "MH3GSaveConverter-Portable-x64.exe",
@@ -228,6 +229,7 @@ def verify_local_packaging_script() -> None:
     for expected in (
         "-p:PublishSingleFile=true",
         "-p:IncludeAllContentForSelfExtract=true",
+        "-p:Version=$Version",
         "mh3g-save-convert.exe",
         "finally",
         "Remove-Item -LiteralPath $embeddedSidecar",
@@ -414,6 +416,41 @@ def main() -> int:
     require("startInfo.Arguments" not in bridge, "CLI bridge must not build a command-string argument list")
     require("cmd.exe" not in bridge and "powershell" not in bridge.lower(), "CLI bridge must not invoke a shell")
 
+    update_service = read("Services/GitHubUpdateService.cs")
+    for expected in (
+        "https://api.github.com/repos/MHToolkit/mh-save-sync/releases/latest",
+        "https://github.com/MHToolkit/mh-save-sync/releases/latest",
+        "https://github.com/MHToolkit/mh-save-sync/releases.atom",
+        "application/vnd.github+json",
+        "application/atom+xml",
+        "X-GitHub-Api-Version",
+        "MH3GSaveConverter/",
+        "TimeSpan.FromSeconds(8)",
+        "MHToolkit/mh-save-sync/releases/",
+        "AssemblyInformationalVersionAttribute",
+        "FetchFromWebFeedAsync",
+        "FetchFromApiAsync",
+        "RangeHeaderValue(0, 0)",
+        "HttpCompletionOption.ResponseHeadersRead",
+        "XDocument.Load",
+        "DtdProcessing.Prohibit",
+    ):
+        require(expected in update_service, f"Windows update service is missing {expected}")
+    require(
+        update_service.index("FetchFromWebFeedAsync(cancellationToken)")
+        < update_service.index("FetchFromApiAsync(cancellationToken)"),
+        "Windows update checks must avoid anonymous API quotas by preferring the official release page/feed",
+    )
+    update_store = read("Services/UpdateCheckPreferenceStore.cs")
+    for expected in (
+        "update-check.json",
+        "ShouldCheckToday",
+        "MarkAttempt",
+        '"yyyy-MM-dd"',
+        "LocalApplicationData",
+    ):
+        require(expected in update_store, f"Windows daily update gate is missing {expected}")
+
     launcher = (ROOT / "scripts" / "mh3g-windows-launcher.ps1").read_text(encoding="utf-8")
     require(
         'Join-Path $PSScriptRoot "tools/mh3g-save-convert.exe"' in launcher,
@@ -578,6 +615,16 @@ def main() -> int:
     require("private void GoToOptionalConfiguration_Click" in code_behind, "optional configuration CTA handler is missing")
     require("OptionalConfigurationAnchor.StartBringIntoView();" in code_behind, "optional configuration CTA must scroll to its controls")
     require("private void GoToPostWriteDestination_Click" in code_behind, "post-write destination handler is missing")
+    for expected in (
+        "RootGrid_Loaded",
+        "About_Click",
+        "CheckForUpdatesAsync(manual: false)",
+        "_updateCheckStore.MarkAttempt();",
+        "ShowUpdateAvailableAsync",
+        "ProcessStartInfo(release.HtmlUrl)",
+        "UseShellExecute = true",
+    ):
+        require(expected in code_behind, f"WinUI update-check flow is missing {expected}")
 
     cec_write = workflow.split("public async Task WriteCecAsync()", 1)[1].split(
         "public async Task RollbackCecAsync()", 1
@@ -792,6 +839,11 @@ def main() -> int:
         "Optional ExtData",
         "可选 ExtData",
         "ExtDataInstallUnavailable",
+        "About & Updates",
+        "关于与更新",
+        "Check for Updates",
+        "检查更新",
+        "UpdateNetworkNote",
     ):
         require(expected in copy, f"localized copy is missing {expected}")
     require((APP / "README.zh-CN.md").is_file(), "Windows shell must include Chinese usage guidance")