Bump version.

.github/workflows/beta-release.yml

@@ -0,0 +1,187 @@
+name: Manual Beta Release
+
+on:
+  workflow_dispatch:
+    inputs:
+      release_title:
+        description: Optional GitHub release title override
+        required: false
+        type: string
+
+permissions:
+  contents: write
+  packages: read
+
+jobs:
+  release-beta:
+    name: Build and publish beta release
+    runs-on: windows-latest
+    env:
+      PROJECT_PATH: Wino.Mail.WinUI/Wino.Mail.WinUI.csproj
+      MANIFEST_PATH: Wino.Mail.WinUI/Package.appxmanifest
+      CHANGELOG_PATH: CHANGELOG.md
+      NUGET_CONFIG_PATH: ${{ github.workspace }}\nuget.config
+      PACKAGE_OUTPUT_DIR: ${{ github.workspace }}\artifacts\package
+      RELEASE_OUTPUT_DIR: ${{ github.workspace }}\artifacts\release
+      CERTIFICATE_PFX_PATH: ${{ github.workspace }}\artifacts\signing\beta-signing-cert.pfx
+      CERTIFICATE_CER_PATH: ${{ github.workspace }}\artifacts\release\Wino-Mail-Beta.cer
+    steps:
+      - name: Checkout selected branch
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.ref }}
+          fetch-depth: 0
+
+      - name: Fetch tags from origin
+        shell: pwsh
+        run: git fetch origin --force --tags
+
+      - name: Validate release secrets
+        shell: pwsh
+        env:
+          BETA_SIGNING_CERT_PFX_BASE64: ${{ secrets.BETA_SIGNING_CERT_PFX_BASE64 }}
+        run: |
+          if ([string]::IsNullOrWhiteSpace($env:BETA_SIGNING_CERT_PFX_BASE64)) {
+            throw "Missing required secret: BETA_SIGNING_CERT_PFX_BASE64"
+          }
+
+      - name: Setup .NET SDK
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
+        env:
+          NUGET_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Compute beta version and release metadata
+        id: metadata
+        shell: pwsh
+        env:
+          RELEASE_TITLE_INPUT: ${{ github.event.inputs.release_title }}
+        run: |
+          $manifestPath = Join-Path $env:GITHUB_WORKSPACE $env:MANIFEST_PATH
+          if (-not (Test-Path $manifestPath)) {
+            throw "Package manifest not found: $manifestPath"
+          }
+
+          $changelogPath = Join-Path $env:GITHUB_WORKSPACE $env:CHANGELOG_PATH
+          if (-not (Test-Path $changelogPath)) {
+            throw "Release notes file not found: $changelogPath"
+          }
+
+          [xml]$manifest = Get-Content -LiteralPath $manifestPath
+          $identityNode = $manifest.Package.Identity
+          if (-not $identityNode) {
+            throw "Could not locate the Package/Identity node in $manifestPath"
+          }
+
+          $currentVersionText = [string]$identityNode.Version
+          if ($currentVersionText -notmatch '^(?<major>\d+)\.(?<minor>\d+)\.(?<patch>\d+)\.(?<revision>\d+)$') {
+            throw "Manifest version '$currentVersionText' is not a four-part numeric version."
+          }
+
+          $packageVersion = $currentVersionText
+          $releaseTag = "v$packageVersion"
+          $releaseTitleInput = $env:RELEASE_TITLE_INPUT
+          $releaseTitle = if ([string]::IsNullOrWhiteSpace($releaseTitleInput)) { $releaseTag } else { $releaseTitleInput.Trim() }
+
+          $headSha = (git rev-parse HEAD).Trim()
+          if ([string]::IsNullOrWhiteSpace($headSha)) {
+            throw "Failed to resolve the checked out commit SHA."
+          }
+
+          $notesInput = Get-Content -LiteralPath $changelogPath -Raw
+          if ([string]::IsNullOrWhiteSpace($notesInput)) {
+            throw "Release notes file is empty: $changelogPath"
+          }
+
+          $notesInput = $notesInput.Trim()
+          New-Item -ItemType Directory -Path $env:RELEASE_OUTPUT_DIR -Force | Out-Null
+          $releaseNotesPath = Join-Path $env:RELEASE_OUTPUT_DIR 'beta-release-notes.md'
+          $notesInput | Set-Content -LiteralPath $releaseNotesPath -Encoding utf8
+
+          "package_version=$packageVersion" >> $env:GITHUB_OUTPUT
+          "release_tag=$releaseTag" >> $env:GITHUB_OUTPUT
+          "release_title=$releaseTitle" >> $env:GITHUB_OUTPUT
+          "release_notes_path=$releaseNotesPath" >> $env:GITHUB_OUTPUT
+          "head_sha=$headSha" >> $env:GITHUB_OUTPUT
+
+      - name: Materialize signing certificate
+        shell: pwsh
+        env:
+          BETA_SIGNING_CERT_PFX_BASE64: ${{ secrets.BETA_SIGNING_CERT_PFX_BASE64 }}
+        run: |
+          $signingDir = Split-Path -Parent $env:CERTIFICATE_PFX_PATH
+          New-Item -ItemType Directory -Path $signingDir -Force | Out-Null
+          [IO.File]::WriteAllBytes($env:CERTIFICATE_PFX_PATH, [Convert]::FromBase64String($env:BETA_SIGNING_CERT_PFX_BASE64))
+
+          $certificate = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($env:CERTIFICATE_PFX_PATH, $null, [System.Security.Cryptography.X509Certificates.X509KeyStorageFlags]::Exportable)
+
+          New-Item -ItemType Directory -Path (Split-Path -Parent $env:CERTIFICATE_CER_PATH) -Force | Out-Null
+          [IO.File]::WriteAllBytes($env:CERTIFICATE_CER_PATH, $certificate.Export([System.Security.Cryptography.X509Certificates.X509ContentType]::Cert))
+
+      - name: Restore WinUI project dependencies
+        shell: pwsh
+        run: |
+          if (-not (Test-Path $env:NUGET_CONFIG_PATH)) {
+            throw "NuGet config file not found: $env:NUGET_CONFIG_PATH"
+          }
+
+          dotnet restore $env:PROJECT_PATH `
+            --configfile $env:NUGET_CONFIG_PATH `
+            -p:Platform=x64 `
+            /p:RestoreConfigFile="$env:NUGET_CONFIG_PATH"
+
+      - name: Build MSIX bundle
+        shell: pwsh
+        run: |
+          New-Item -ItemType Directory -Path $env:PACKAGE_OUTPUT_DIR -Force | Out-Null
+
+          dotnet build $env:PROJECT_PATH `
+            --configuration Release `
+            --no-restore `
+            --configfile $env:NUGET_CONFIG_PATH `
+            /p:Platform=x64 `
+            /p:RestoreConfigFile="$env:NUGET_CONFIG_PATH" `
+            /p:GenerateAppxPackageOnBuild=true `
+            /p:UapAppxPackageBuildMode=SideloadOnly `
+            /p:AppxBundle=Always `
+            /p:AppxBundlePlatforms="x86|x64|arm64" `
+            /p:AppxPackageDir="$env:PACKAGE_OUTPUT_DIR\\" `
+            /p:AppxPackageVersion=${{ steps.metadata.outputs.package_version }} `
+            /p:PackageCertificateKeyFile="$env:CERTIFICATE_PFX_PATH" `
+            /p:PackageCertificatePassword= `
+            /p:PackageCertificateThumbprint= `
+            /p:AppxPackageSigningEnabled=true
+
+      - name: Collect packaged artifacts
+        id: package
+        shell: pwsh
+        run: |
+          $bundle = Get-ChildItem -Path $env:PACKAGE_OUTPUT_DIR -Recurse -Filter *.msixbundle | Select-Object -First 1
+          if (-not $bundle) {
+            throw "No .msixbundle file was generated under $env:PACKAGE_OUTPUT_DIR"
+          }
+
+          $releaseAssetPath = Join-Path $env:RELEASE_OUTPUT_DIR "Wino_${{ steps.metadata.outputs.package_version }}.zip"
+          if (Test-Path $releaseAssetPath) {
+            Remove-Item -LiteralPath $releaseAssetPath -Force
+          }
+
+          Compress-Archive -LiteralPath @($bundle.FullName, $env:CERTIFICATE_CER_PATH) -DestinationPath $releaseAssetPath -Force
+
+          "bundle_path=$($bundle.FullName)" >> $env:GITHUB_OUTPUT
+          "bundle_name=$($bundle.Name)" >> $env:GITHUB_OUTPUT
+          "release_asset_path=$releaseAssetPath" >> $env:GITHUB_OUTPUT
+
+      - name: Create GitHub prerelease
+        shell: pwsh
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          gh release create "${{ steps.metadata.outputs.release_tag }}" `
+            "${{ steps.package.outputs.release_asset_path }}" `
+            --repo "${{ github.repository }}" `
+            --target "${{ steps.metadata.outputs.head_sha }}" `
+            --title "${{ steps.metadata.outputs.release_title }}" `
+            --notes-file "${{ steps.metadata.outputs.release_notes_path }}" `
+            --prerelease

.github/workflows/pr-winui-build.yml

@@ -1,125 +0,0 @@
-name: PR WinUI Build
-
-on:
-  pull_request:
-    types:
-      - opened
-      - synchronize
-      - reopened
-      - ready_for_review
-
-permissions:
-  contents: read
-  packages: read
-
-jobs:
-  build-winui:
-    name: Build project (${{ matrix.platform }})
-    if: github.event.pull_request.draft == false
-    runs-on: windows-latest
-    continue-on-error: ${{ contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.pull_request.author_association) }}
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          - platform: x86
-            rid: win-x86
-          - platform: x64
-            rid: win-x64
-          - platform: ARM64
-            rid: win-arm64
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Setup .NET SDK
-        uses: actions/setup-dotnet@v4
-        with:
-          dotnet-version: 10.0.x
-          source-url: https://nuget.pkg.github.com/bkaankose/index.json
-        env:
-          NUGET_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Restore WinUI project dependencies
-        run: dotnet restore Wino.Mail.WinUI/Wino.Mail.WinUI.csproj --configfile nuget.config -p:Platform=${{ matrix.platform }} -p:RuntimeIdentifier=${{ matrix.rid }}
-
-      - name: Build WinUI project
-        run: dotnet build Wino.Mail.WinUI/Wino.Mail.WinUI.csproj --configuration Release --no-restore -p:Platform=${{ matrix.platform }} -p:RuntimeIdentifier=${{ matrix.rid }} -p:GenerateAppxPackageOnBuild=false -p:AppxPackageSigningEnabled=false
-
-  core-tests:
-    name: Run Core tests
-    if: github.event.pull_request.draft == false
-    runs-on: windows-latest
-    continue-on-error: ${{ contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.pull_request.author_association) }}
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-
-      - name: Setup .NET SDK
-        uses: actions/setup-dotnet@v4
-        with:
-          dotnet-version: 10.0.x
-          source-url: https://nuget.pkg.github.com/bkaankose/index.json
-        env:
-          NUGET_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Restore Core test projects
-        shell: pwsh
-        run: |
-          $coreTests = Get-ChildItem -Path . -Recurse -Filter "*Core*.Tests.csproj" | ForEach-Object { $_.FullName }
-          if (-not $coreTests) {
-            throw "No Core test projects were found."
-          }
-
-          foreach ($project in $coreTests) {
-            dotnet restore $project --configfile nuget.config
-          }
-
-      - name: Run Core test projects
-        shell: pwsh
-        run: |
-          New-Item -ItemType Directory -Path TestResults -Force | Out-Null
-          $coreTests = Get-ChildItem -Path . -Recurse -Filter "*Core*.Tests.csproj"
-          if (-not $coreTests) {
-            throw "No Core test projects were found."
-          }
-
-          foreach ($project in $coreTests) {
-            $name = $project.BaseName
-            dotnet test $project.FullName --configuration Release --no-restore --verbosity normal --logger "trx;LogFileName=$name.trx" --results-directory TestResults
-          }
-
-      - name: Upload Core test result artifacts
-        if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: core-test-results
-          path: TestResults/*.trx
-          if-no-files-found: warn
-
-      - name: Publish Core test report
-        if: always()
-        uses: EnricoMi/publish-unit-test-result-action/windows@v2
-        with:
-          trx_files: TestResults/*.trx
-          check_name: Core test results
-
-  enforce-for-non-maintainers:
-    name: Enforce required checks (non-maintainers)
-    if: github.event.pull_request.draft == false && !contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.pull_request.author_association)
-    runs-on: ubuntu-latest
-    needs:
-      - build-winui
-      - core-tests
-
-    steps:
-      - name: Fail when build or tests fail for non-maintainers
-        if: needs.build-winui.result != 'success' || needs.core-tests.result != 'success'
-        run: |
-          echo "WinUI build and Core tests must pass for non-maintainer pull requests."
-          exit 1
-
-      - name: Confirm build and test success for non-maintainers
-        run: echo "WinUI build and Core tests passed."

AGENTS.md

@@ -150,6 +150,8 @@ private string searchQuery = string.Empty;
 - For dependency properties in WinUI code, always prefer `[GeneratedDependencyProperty]` from CommunityToolkit over manual `DependencyProperty.Register(...)` declarations.
 - When a `[RelayCommand]` needs enable/disable logic, prefer the command's `CanExecute` over binding `Button.IsEnabled` in XAML; use `[NotifyCanExecuteChangedFor]` on dependent properties and call `NotifyCanExecuteChanged()` explicitly when non-generated state affects the command.
 - In ViewModels, update all UI-bound properties/collections via `ExecuteUIThread(...)` (especially after awaited calls and any use of `ConfigureAwait(false)`).
+- `ConfigureAwait(false)` continues execution on a background thread. Any UI-bound property change, `INotifyPropertyChanged` notification, collection mutation, or similar UI-facing state update after that point must be marshaled back with `ExecuteUIThread(...)` or the appropriate dispatcher call, otherwise the app can crash.
+- Messenger messages are raised from a background thread by default, while UI control event handlers such as `Button.Click` start on the UI thread. Be deliberate when combining dispatcher usage with `ConfigureAwait(false)` so post-await UI updates always return to the UI thread.
 - ViewModels should only handle UI interaction/state and delegate business logic to services; account-management work belongs in `WinoAccountProfileService`, and preferences import/export/apply logic belongs in `PreferencesService`.
 - In `EventDetailsPageViewModel.LoadAttendeesAsync`, never mutate `CurrentEvent.Attendees` outside `ExecuteUIThread(...)`.
 - Never create pure C# controls or controls that heavily manipulate UI structure from `.cs` files. Define controls in XAML and keep UI composition in XAML.

Wino.Calendar.ViewModels/CalendarAppShellViewModel.cs

@@ -169,6 +169,7 @@ public partial class CalendarAppShellViewModel : CalendarBaseViewModel,
 
         var activationContext = parameters as ShellModeActivationContext;
         var shouldRunStartupFlows = activationContext?.IsInitialActivation ?? true;
+        var navigationArgs = activationContext?.Parameter as CalendarPageNavigationArgs;
 
         PreferencesService.PreferenceChanged -= PreferencesServiceChanged;
         PreferencesService.PreferenceChanged += PreferencesServiceChanged;
@@ -178,7 +179,14 @@ public partial class CalendarAppShellViewModel : CalendarBaseViewModel,
         await InitializeAccountCalendarsAsync();
         ValidateConfiguredNewEventCalendar();
 
-        TodayClicked();
+        if (navigationArgs != null)
+        {
+            NavigationService.Navigate(WinoPage.CalendarPage, navigationArgs);
+        }
+        else if (shouldRunStartupFlows || _calendarPageViewModel.CurrentVisibleRange == null)
+        {
+            TodayClicked();
+        }
     }
 
     public override void OnNavigatedFrom(NavigationMode mode, object parameters)

Wino.Calendar.ViewModels/CalendarPageViewModel.cs

@@ -86,6 +86,7 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         get
         {
             if (SelectedQuickEventAccountCalendar == null ||
+                SelectedQuickEventAccountCalendar.IsReadOnly ||
                 SelectedQuickEventDate == null ||
                 string.IsNullOrWhiteSpace(EventName) ||
                 string.IsNullOrWhiteSpace(SelectedStartTimeString) ||
@@ -204,6 +205,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (DisplayDetailsCalendarItemViewModel?.CalendarItem == null)
             return;
 
+        if (DisplayDetailsCalendarItemViewModel.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         if (DisplayDetailsCalendarItemViewModel.CalendarItem.IsRecurringParent)
         {
             var confirmed = await _dialogService.ShowConfirmationDialogAsync(
@@ -460,6 +467,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
     [RelayCommand(AllowConcurrentExecutions = false, CanExecute = nameof(CanSaveQuickEvent))]
     private async Task SaveQuickEventAsync()
     {
+        if (SelectedQuickEventAccountCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var startDate = IsAllDay ? SelectedQuickEventDate.Value.Date : QuickEventStartTime;
         var endDate = IsAllDay ? SelectedQuickEventDate.Value.Date.AddDays(1) : QuickEventEndTime;
         var composeResult = new CalendarEventComposeResult
@@ -553,6 +566,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
             return;
         }
 
+        if (calendarItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var normalizedTargetStart = calendarItem.IsAllDayEvent
             ? targetStart.Date
             : targetStart;
@@ -615,7 +634,7 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         }
     }
 
-    public async Task ApplyDisplayRequestAsync(CalendarDisplayRequest request, bool forceReload = false)
+    public async Task ApplyDisplayRequestAsync(CalendarDisplayRequest request, bool forceReload = false, CalendarItemTarget pendingTarget = null)
     {
         var lifetimeVersion = CurrentPageLifetimeVersion;
         var hasLoadingLock = await WaitForCalendarLoadingLockAsync(lifetimeVersion).ConfigureAwait(false);
@@ -699,6 +718,11 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
             await _notificationBuilder.ClearCalendarTaskbarBadgeAsync().ConfigureAwait(false);
             _isCalendarBadgeClearedForPageLifetime = true;
         }
+
+        if (loadSucceeded && pendingTarget != null && IsPageActive(lifetimeVersion))
+        {
+            await NavigateToPendingCalendarTargetAsync(pendingTarget).ConfigureAwait(false);
+        }
     }
 
     public Task ReloadCurrentVisibleRangeAsync()
@@ -726,6 +750,31 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         NavigateEvent(new CalendarItemViewModel(calendarItem), CalendarEventTargetType.Single);
     }
 
+    private async Task NavigateToPendingCalendarTargetAsync(CalendarItemTarget target)
+    {
+        CalendarItemViewModel calendarItemViewModel = null;
+
+        if (_loadedCalendarItems.TryGetValue(target.Item.Id, out var loadedCalendarItemViewModel))
+        {
+            calendarItemViewModel = loadedCalendarItemViewModel;
+        }
+        else
+        {
+            var targetItem = await _calendarService.GetCalendarItemTargetAsync(target).ConfigureAwait(false);
+            if (targetItem == null)
+                return;
+
+            targetItem.AssignedCalendar ??= AccountCalendarStateService.ActiveCalendars.FirstOrDefault(calendar => calendar.Id == targetItem.CalendarId);
+            calendarItemViewModel = new CalendarItemViewModel(targetItem);
+        }
+
+        await ExecuteUIThread(() =>
+        {
+            DisplayDetailsCalendarItemViewModel = calendarItemViewModel;
+            NavigateEvent(calendarItemViewModel, target.TargetType);
+        }).ConfigureAwait(false);
+    }
+
     private async Task<List<CalendarItemViewModel>> LoadCalendarItemsAsync(DateRange loadedDateWindow, long lifetimeVersion)
     {
         var loadedItems = new Dictionary<Guid, CalendarItemViewModel>();
@@ -800,7 +849,7 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
     }
 
     public async void Receive(LoadCalendarMessage message)
-        => await ApplyDisplayRequestAsync(message.DisplayRequest, message.ForceReload);
+        => await ApplyDisplayRequestAsync(message.DisplayRequest, message.ForceReload, message.PendingTarget);
 
     public void Receive(CalendarSettingsUpdatedMessage message)
     {
@@ -1195,6 +1244,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (targetItem == null)
             return;
 
+        if (targetItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         if (targetItem.IsRecurringParent)
         {
             var confirmed = await _dialogService.ShowConfirmationDialogAsync(
@@ -1221,6 +1276,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (targetItem == null || targetItem.ShowAs == showAs)
             return;
 
+        if (targetItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var originalItem = await _calendarService.GetCalendarItemAsync(targetItem.Id).ConfigureAwait(false);
         var attendees = await _calendarService.GetAttendeesAsync(targetItem.Id).ConfigureAwait(false);
 
@@ -1245,6 +1306,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (targetItem == null)
             return;
 
+        if (targetItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var operation = responseStatus switch
         {
             CalendarItemStatus.Accepted => CalendarSynchronizerOperation.AcceptEvent,

Wino.Calendar.ViewModels/Data/AccountCalendarViewModel.cs

@@ -55,6 +55,12 @@ public partial class AccountCalendarViewModel : ObservableObject, IAccountCalend
         set => SetProperty(AccountCalendar.IsPrimary, value, AccountCalendar, (u, i) => u.IsPrimary = i);
     }
 
+    public bool IsReadOnly
+    {
+        get => AccountCalendar.IsReadOnly;
+        set => SetProperty(AccountCalendar.IsReadOnly, value, AccountCalendar, (u, i) => u.IsReadOnly = i);
+    }
+
     public bool IsSynchronizationEnabled
     {
         get => AccountCalendar.IsSynchronizationEnabled;

Wino.Calendar.ViewModels/EventDetailsPageViewModel.cs

@@ -440,6 +440,11 @@ public partial class EventDetailsPageViewModel : CalendarBaseViewModel
     private async Task SaveAsync()
     {
         if (CurrentEvent == null) return;
+        if (CurrentEvent.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
 
         try
         {
@@ -506,6 +511,11 @@ public partial class EventDetailsPageViewModel : CalendarBaseViewModel
     private async Task DeleteAsync()
     {
         if (CurrentEvent == null) return;
+        if (CurrentEvent.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
 
         // If the event is a master recurring event, ask for confirmation
         if (CurrentEvent.IsRecurringParent)
@@ -610,6 +620,11 @@ public partial class EventDetailsPageViewModel : CalendarBaseViewModel
     private async Task SendRsvpResponse(AttendeeStatus status)
     {
         if (CurrentEvent == null) return;
+        if (CurrentEvent.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
 
         try
         {

Wino.Core.Domain/Constants.cs

@@ -24,6 +24,7 @@ public static class Constants
     public const string ToastModeKey = nameof(ToastModeKey);
     public const string ToastModeMail = nameof(ToastModeMail);
     public const string ToastModeCalendar = nameof(ToastModeCalendar);
+    public const string ToastDismissActionKey = nameof(ToastDismissActionKey);
     public const string ToastStoreUpdateActionKey = nameof(ToastStoreUpdateActionKey);
     public const string ToastStoreUpdateActionInstall = nameof(ToastStoreUpdateActionInstall);
     public const string ClientLogFile = "Client_.log";

Wino.Core.Domain/Entities/Calendar/AccountCalendar.cs

@@ -16,6 +16,7 @@ public class AccountCalendar : IAccountCalendar
     public string SynchronizationDeltaToken { get; set; }
     public string Name { get; set; }
     public bool IsPrimary { get; set; }
+    public bool IsReadOnly { get; set; }
     public bool IsSynchronizationEnabled { get; set; } = true;
     public bool IsExtended { get; set; } = true;
     public CalendarItemShowAs DefaultShowAs { get; set; } = CalendarItemShowAs.Busy;

Wino.Core.Domain/Entities/Mail/MailCategory.cs

@@ -0,0 +1,25 @@
+using System;
+using SQLite;
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Core.Domain.Entities.Mail;
+
+public class MailCategory
+{
+    [PrimaryKey]
+    public Guid Id { get; set; }
+
+    public Guid MailAccountId { get; set; }
+
+    public string RemoteId { get; set; }
+
+    public string Name { get; set; }
+
+    public bool IsFavorite { get; set; }
+
+    public string BackgroundColorHex { get; set; }
+
+    public string TextColorHex { get; set; }
+
+    public MailCategorySource Source { get; set; } = MailCategorySource.Local;
+}

Wino.Core.Domain/Entities/Mail/MailCategoryAssignment.cs

@@ -0,0 +1,14 @@
+using System;
+using SQLite;
+
+namespace Wino.Core.Domain.Entities.Mail;
+
+public class MailCategoryAssignment
+{
+    [PrimaryKey]
+    public Guid Id { get; set; }
+
+    public Guid MailCategoryId { get; set; }
+
+    public Guid MailCopyUniqueId { get; set; }
+}

Wino.Core.Domain/Entities/Shared/MailAccount.cs

@@ -112,6 +112,16 @@ public class MailAccount
     /// </summary>
     public DateTime? LastFolderStructureSyncDate { get; set; }
 
+    /// <summary>
+    /// Gets or sets when the account was created in Wino.
+    /// </summary>
+    public DateTime? CreatedAt { get; set; }
+
+    /// <summary>
+    /// Gets or sets the timespan used for the account's initial mail synchronization.
+    /// </summary>
+    public InitialSynchronizationRange InitialSynchronizationRange { get; set; } = InitialSynchronizationRange.SixMonths;
+
     /// <summary>
     /// Gets whether the account can perform ProfileInformation sync type.
     /// </summary>
@@ -122,5 +132,10 @@ public class MailAccount
     /// </summary>
     public bool IsAliasSyncSupported => ProviderType == MailProviderType.Gmail || ProviderType == MailProviderType.Outlook;
 
+    /// <summary>
+    /// Gets whether the account can perform category definition sync type.
+    /// </summary>
+    public bool IsCategorySyncSupported => ProviderType == MailProviderType.Outlook;
+
     public override string ToString() => Name;
 }

Wino.Core.Domain/Enums/InitialSynchronizationRange.cs

@@ -0,0 +1,10 @@
+namespace Wino.Core.Domain.Enums;
+
+public enum InitialSynchronizationRange
+{
+    SixMonths = 0,
+    ThreeMonths = 1,
+    NineMonths = 2,
+    OneYear = 3,
+    Everything = 4
+}

Wino.Core.Domain/Enums/MailCategorySource.cs

@@ -0,0 +1,7 @@
+namespace Wino.Core.Domain.Enums;
+
+public enum MailCategorySource
+{
+    Local,
+    Outlook
+}

Wino.Core.Domain/Enums/MailOperation.cs

@@ -13,6 +13,7 @@ public enum MailSynchronizerOperation
     AlwaysMoveTo,
     MoveToFocused,
     Archive,
+    UpdateCategories,
 }
 
 public enum FolderSynchronizerOperation
@@ -35,6 +36,13 @@ public enum CalendarSynchronizerOperation
     TentativeEvent,
 }
 
+public enum CategorySynchronizerOperation
+{
+    CreateCategory,
+    UpdateCategory,
+    DeleteCategory,
+}
+
 // UI requests
 public enum MailOperation
 {

Wino.Core.Domain/Enums/MailSynchronizationType.cs

@@ -3,6 +3,7 @@
 public enum MailSynchronizationType
 {
     UpdateProfile, // Only update profile information
+    Categories, // Only update mail categories
     ExecuteRequests, // Run the queued requests, and then synchronize if needed.
     FoldersOnly, // Only synchronize folder metadata.
     InboxOnly, // Only Inbox, Sent, Draft and Deleted folders.

Wino.Core.Domain/Enums/WinoPage.cs

@@ -19,11 +19,13 @@ public enum WinoPage
     AboutPage,
     PersonalizationPage,
     MessageListPage,
+    MailNotificationSettingsPage,
     MailListPage,
     ReadComposePanePage,
     AppPreferencesPage,
     SettingOptionsPage,
     AliasManagementPage,
+    MailCategoryManagementPage,
     ImapCalDavSettingsPage,
     KeyboardShortcutsPage,
     CalendarPage,

Wino.Core.Domain/Extensions/InitialSynchronizationRangeExtensions.cs

@@ -0,0 +1,23 @@
+using System;
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Core.Domain.Extensions;
+
+public static class InitialSynchronizationRangeExtensions
+{
+    public static DateTime? ToCutoffDateUtc(this InitialSynchronizationRange range, DateTime utcNow)
+    {
+        var normalizedUtcNow = utcNow.Kind == DateTimeKind.Utc
+            ? utcNow
+            : utcNow.ToUniversalTime();
+
+        return range switch
+        {
+            InitialSynchronizationRange.ThreeMonths => normalizedUtcNow.AddMonths(-3),
+            InitialSynchronizationRange.SixMonths => normalizedUtcNow.AddMonths(-6),
+            InitialSynchronizationRange.NineMonths => normalizedUtcNow.AddMonths(-9),
+            InitialSynchronizationRange.OneYear => normalizedUtcNow.AddYears(-1),
+            _ => null
+        };
+    }
+}

Wino.Core.Domain/Interfaces/IAccountCalendar.cs

@@ -10,6 +10,7 @@ public interface IAccountCalendar
     string TextColorHex { get; set; }
     string BackgroundColorHex { get; set; }
     bool IsPrimary { get; set; }
+    bool IsReadOnly { get; set; }
     bool IsSynchronizationEnabled { get; set; }
     Guid AccountId { get; set; }
     string RemoteCalendarId { get; set; }

Wino.Core.Domain/Interfaces/IFolderMenuItem.cs

@@ -14,6 +14,22 @@ public interface IFolderMenuItem : IBaseFolderMenuItem
 
 public interface IMergedAccountFolderMenuItem : IBaseFolderMenuItem { }
 
+public interface IMailCategoryMenuItem : IBaseFolderMenuItem
+{
+    Entities.Mail.MailCategory MailCategory { get; }
+    string TextColorHex { get; }
+    string BackgroundColorHex { get; }
+    bool HasTextColor { get; }
+}
+
+public interface IMergedMailCategoryMenuItem : IBaseFolderMenuItem
+{
+    IReadOnlyList<Entities.Mail.MailCategory> Categories { get; }
+    string TextColorHex { get; }
+    string BackgroundColorHex { get; }
+    bool HasTextColor { get; }
+}
+
 public interface IBaseFolderMenuItem : IMenuItem
 {
     string FolderName { get; }

Wino.Core.Domain/Interfaces/IMailCategoryService.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Models.Accounts;
+
+namespace Wino.Core.Domain.Interfaces;
+
+public interface IMailCategoryService
+{
+    Task<List<MailCategory>> GetCategoriesAsync(Guid accountId);
+    Task<List<MailCategory>> GetFavoriteCategoriesAsync(Guid accountId);
+    Task<MailCategory> GetCategoryAsync(Guid categoryId);
+    Task<bool> CategoryNameExistsAsync(Guid accountId, string name, Guid? excludedCategoryId = null);
+    Task<MailCategory> CreateCategoryAsync(MailCategory category);
+    Task UpdateCategoryAsync(MailCategory category);
+    Task DeleteCategoryAsync(Guid categoryId);
+    Task DeleteCategoriesAsync(Guid accountId);
+    Task ToggleFavoriteAsync(Guid categoryId, bool isFavorite);
+    Task UpdateRemoteIdAsync(Guid categoryId, string remoteId);
+    Task ReplaceCategoriesAsync(Guid accountId, IEnumerable<MailCategory> categories);
+    Task ReplaceMailAssignmentsAsync(Guid accountId, Guid mailCopyUniqueId, IEnumerable<string> categoryNames);
+    Task AssignCategoryAsync(Guid categoryId, IEnumerable<Guid> mailCopyUniqueIds);
+    Task UnassignCategoryAsync(Guid categoryId, IEnumerable<Guid> mailCopyUniqueIds);
+    Task<List<MailCategory>> GetCategoriesForMailAsync(Guid accountId, IEnumerable<Guid> mailCopyUniqueIds);
+    Task<List<Guid>> GetAssignedCategoryIdsForAllAsync(IEnumerable<Guid> mailCopyUniqueIds);
+    Task<List<string>> GetCategoryNamesForMailAsync(Guid mailCopyUniqueId);
+    Task<List<MailCopy>> GetMailCopiesForCategoryAsync(Guid categoryId);
+    Task<List<UnreadCategoryCountResult>> GetUnreadCategoryCountResultsAsync(IEnumerable<Guid> accountIds);
+}

Wino.Core.Domain/Interfaces/IMailDialogService.cs

@@ -11,11 +11,13 @@ using Wino.Core.Domain.Models;
 using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.Calendar;
 using Wino.Core.Domain.Models.Folders;
+using Wino.Core.Domain.Models.MailItem;
 
 namespace Wino.Core.Domain.Interfaces;
 
 public interface IMailDialogService : IDialogServiceBase
 {
+    void ShowReadOnlyCalendarMessage();
     Task<bool> ShowHardDeleteConfirmationAsync();
     Task HandleSystemFolderConfigurationDialogAsync(Guid accountId, IFolderService folderService);
 
@@ -51,6 +53,13 @@ public interface IMailDialogService : IDialogServiceBase
     /// <returns>Created alias model if not canceled.</returns>
     Task<ICreateAccountAliasDialog> ShowCreateAccountAliasDialogAsync();
 
+    /// <summary>
+    /// Presents a dialog to the user for mail category creation/modification.
+    /// </summary>
+#pragma warning disable CS8625
+    Task<MailCategoryDialogResult> ShowEditMailCategoryDialogAsync(MailCategory category = null);
+#pragma warning restore CS8625
+
     /// <summary>
     /// Presents a dialog to the user to show email source.
     /// </summary>

Wino.Core.Domain/Interfaces/INewThemeService.cs

@@ -15,6 +15,7 @@ public interface INewThemeService : IInitializeAsync
     Task<List<AppThemeBase>> GetAvailableThemesAsync();
     Task<CustomThemeMetadata> CreateNewCustomThemeAsync(string themeName, string accentColor, byte[] wallpaperData);
     Task<List<CustomThemeMetadata>> GetCurrentCustomThemesAsync();
+    Task<bool> DeleteCustomThemeAsync(Guid themeId);
     List<string> GetAvailableAccountColors();
     Task ApplyCustomThemeAsync(bool isInitializing);
 

Wino.Core.Domain/Interfaces/IPreferencesService.cs

@@ -192,6 +192,16 @@ public interface IPreferencesService : INotifyPropertyChanged
     /// </summary>
     Guid? StartupEntityId { get; set; }
 
+    /// <summary>
+    /// Setting: First action button displayed on mail toast notifications.
+    /// </summary>
+    MailOperation FirstMailNotificationAction { get; set; }
+
+    /// <summary>
+    /// Setting: Second action button displayed on mail toast notifications.
+    /// </summary>
+    MailOperation SecondMailNotificationAction { get; set; }
+
 
 
     /// <summary>

Wino.Core.Domain/Interfaces/IRequestBundle.cs

@@ -72,3 +72,9 @@ public interface ICalendarActionRequest : IRequestBase
     Guid? LocalCalendarItemId { get; }
     CalendarSynchronizerOperation Operation { get; }
 }
+
+public interface ICategoryActionRequest : IRequestBase
+{
+    Guid AccountId { get; }
+    CategorySynchronizerOperation Operation { get; }
+}

Wino.Core.Domain/Interfaces/IShareActivationService.cs

@@ -0,0 +1,14 @@
+#nullable enable
+using System;
+using Wino.Core.Domain.Models.Launch;
+
+namespace Wino.Core.Domain.Interfaces;
+
+public interface IShareActivationService
+{
+    MailShareRequest? PendingShareRequest { get; set; }
+    MailShareRequest? ConsumePendingShareRequest();
+    void ClearPendingShareRequest();
+    void StagePendingComposeShareRequest(Guid draftUniqueId, MailShareRequest shareRequest);
+    MailShareRequest? ConsumePendingComposeShareRequest(Guid draftUniqueId);
+}

Wino.Core.Domain/Interfaces/ISynchronizationManager.cs

@@ -63,6 +63,12 @@ public interface ISynchronizationManager
     Task<MailSynchronizationResult> SynchronizeAliasesAsync(Guid accountId,
                                                             CancellationToken cancellationToken = default);
 
+    /// <summary>
+    /// Handles category synchronization for the given account.
+    /// </summary>
+    Task<MailSynchronizationResult> SynchronizeCategoriesAsync(Guid accountId,
+                                                               CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Handles profile synchronization for the given account.
     /// </summary>

Wino.Core.Domain/Interfaces/IWinoRequestDelegator.cs

@@ -1,4 +1,6 @@
-using System.Threading.Tasks;
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
 using Wino.Core.Domain.Models.Calendar;
 using Wino.Core.Domain.Models.Folders;
 using Wino.Core.Domain.Models.MailItem;
@@ -36,4 +38,9 @@ public interface IWinoRequestDelegator
     /// </summary>
     /// <param name="calendarOperationPreparationRequest">Calendar preparation request.</param>
     Task ExecuteAsync(CalendarOperationPreparationRequest calendarOperationPreparationRequest);
+
+    /// <summary>
+    /// Queues pre-built requests for a single account and triggers synchronization.
+    /// </summary>
+    Task ExecuteAsync(Guid accountId, IEnumerable<IRequestBase> requests);
 }

Wino.Core.Domain/MenuItems/MailCategoryMenuItem.cs

@@ -0,0 +1,48 @@
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Entities.Shared;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Folders;
+
+namespace Wino.Core.Domain.MenuItems;
+
+public partial class MailCategoryMenuItem : MenuItemBase<MailCategory, IMenuItem>, IFolderMenuItem, IMailCategoryMenuItem
+{
+    private IReadOnlyList<IMailItemFolder> _handlingFolders;
+
+    [ObservableProperty]
+    private int unreadItemCount;
+
+    public MailCategoryMenuItem(MailCategory category, MailAccount parentAccount, IEnumerable<IMailItemFolder> handlingFolders, IMenuItem parentMenuItem)
+        : base(category, category.Id, parentMenuItem)
+    {
+        ParentAccount = parentAccount;
+        _handlingFolders = handlingFolders?.ToList() ?? [];
+    }
+
+    public string FolderName => Parameter.Name;
+    public bool IsSynchronizationEnabled => false;
+    public SpecialFolderType SpecialFolderType => SpecialFolderType.Other;
+    public IEnumerable<IMailItemFolder> HandlingFolders => _handlingFolders;
+    public new ObservableCollection<IMenuItem> SubMenuItems { get; } = [];
+    public bool IsMoveTarget => true;
+    public bool IsSticky => false;
+    public bool IsSystemFolder => false;
+    public bool ShowUnreadCount => true;
+    public string AssignedAccountName => ParentAccount?.Name;
+    public MailAccount ParentAccount { get; private set; }
+    public string TextColorHex => Parameter.TextColorHex;
+    public string BackgroundColorHex => Parameter.BackgroundColorHex;
+    public bool HasTextColor => !string.IsNullOrWhiteSpace(Parameter.TextColorHex);
+    public MailCategory MailCategory => Parameter;
+
+    public void UpdateFolder(IMailItemFolder folder)
+    {
+    }
+
+    public void UpdateParentAccounnt(MailAccount account) => ParentAccount = account;
+}

Wino.Core.Domain/MenuItems/MenuItemCollection.cs

@@ -22,11 +22,13 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public IEnumerable<IAccountMenuItem> GetAllAccountMenuItems()
     {
-        foreach (var item in this)
+        var rootItems = this.ToList();
+
+        foreach (var item in rootItems)
         {
             if (item is MergedAccountMenuItem mergedAccountMenuItem)
             {
-                foreach (var singleItem in mergedAccountMenuItem.SubMenuItems.OfType<IAccountMenuItem>())
+                foreach (var singleItem in mergedAccountMenuItem.SubMenuItems.OfType<IAccountMenuItem>().ToList())
                 {
                     yield return singleItem;
                 }
@@ -40,9 +42,11 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public IEnumerable<IBaseFolderMenuItem> GetAllFolderMenuItems(Guid folderId)
     {
-        foreach (var item in this)
+        var rootItems = this.ToList();
+
+        foreach (var item in rootItems)
         {
-            if (item is IBaseFolderMenuItem folderMenuItem)
+            if (item is IBaseFolderMenuItem folderMenuItem && item is not IMailCategoryMenuItem && item is not IMergedMailCategoryMenuItem)
             {
                 if (folderMenuItem.HandlingFolders.Any(a => a.Id == folderId))
                 {
@@ -50,7 +54,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
                 }
                 else if (folderMenuItem.SubMenuItems.Any())
                 {
-                    foreach (var subItem in folderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>())
+                    foreach (var subItem in folderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>().ToList())
                     {
                         if (subItem.HandlingFolders.Any(a => a.Id == folderId))
                         {
@@ -65,8 +69,10 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public bool TryGetAccountMenuItem(Guid accountId, out IAccountMenuItem value)
     {
-        value = this.OfType<AccountMenuItem>().FirstOrDefault(a => a.AccountId == accountId);
-        value ??= this.OfType<MergedAccountMenuItem>().FirstOrDefault(a => a.SubMenuItems.OfType<AccountMenuItem>().Where(b => b.AccountId == accountId) != null);
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<AccountMenuItem>().FirstOrDefault(a => a.AccountId == accountId);
+        value ??= rootItems.OfType<MergedAccountMenuItem>().FirstOrDefault(a => a.SubMenuItems.OfType<AccountMenuItem>().Any(b => b.AccountId == accountId));
 
         return value != null;
     }
@@ -74,7 +80,9 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     // Pattern: Look for special folder menu item inside the loaded folders for Windows Mail style menu items.
     public bool TryGetWindowsStyleRootSpecialFolderMenuItem(Guid accountId, SpecialFolderType specialFolderType, out FolderMenuItem value)
     {
-        value = this.OfType<IBaseFolderMenuItem>()
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<IBaseFolderMenuItem>()
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.MailAccountId == accountId && b.SpecialFolderType == specialFolderType)) as FolderMenuItem;
 
         return value != null;
@@ -84,7 +92,9 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     // This will not look for the folders inside individual account menu items inside merged account menu item.
     public bool TryGetMergedAccountSpecialFolderMenuItem(Guid mergedInboxId, SpecialFolderType specialFolderType, out IBaseFolderMenuItem value)
     {
-        value = this.OfType<MergedAccountFolderMenuItem>()
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<MergedAccountFolderMenuItem>()
                 .Where(a => a.MergedInbox.Id == mergedInboxId)
                 .FirstOrDefault(a => a.SpecialFolderType == specialFolderType);
 
@@ -93,11 +103,14 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public bool TryGetFolderMenuItem(Guid folderId, out IBaseFolderMenuItem value)
     {
+        var rootItems = this.ToList();
+
         // Root folders
-        value = this.OfType<IBaseFolderMenuItem>()
+        value = rootItems.OfType<IBaseFolderMenuItem>()
+                .Where(a => a is not IMailCategoryMenuItem && a is not IMergedMailCategoryMenuItem)
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.Id == folderId));
 
-        value ??= this.OfType<FolderMenuItem>()
+        value ??= rootItems.OfType<FolderMenuItem>()
             .SelectMany(a => a.SubMenuItems)
                 .OfType<IBaseFolderMenuItem>()
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.Id == folderId));
@@ -105,10 +118,23 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
         return value != null;
     }
 
+    public bool TryGetCategoryMenuItem(Guid categoryId, out IBaseFolderMenuItem value)
+    {
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<IMailCategoryMenuItem>()
+            .FirstOrDefault(a => a.MailCategory.Id == categoryId);
+
+        value ??= rootItems.OfType<IMergedMailCategoryMenuItem>()
+            .FirstOrDefault(a => a.Categories.Any(b => b.Id == categoryId)) as IBaseFolderMenuItem;
+
+        return value != null;
+    }
+
     public void UpdateUnreadItemCountsToZero()
     {
         // Handle the root folders.
-        foreach (var item in this.OfType<IBaseFolderMenuItem>())
+        foreach (var item in this.OfType<IBaseFolderMenuItem>().ToList())
         {
             RecursivelyResetUnreadItemCount(item);
         }
@@ -120,7 +146,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
         if (baseFolderMenuItem.SubMenuItems == null) return;
 
-        foreach (var subMenuItem in baseFolderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>())
+        foreach (var subMenuItem in baseFolderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>().ToList())
         {
             RecursivelyResetUnreadItemCount(subMenuItem);
         }
@@ -128,7 +154,9 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public bool TryGetSpecialFolderMenuItem(Guid accountId, SpecialFolderType specialFolderType, out FolderMenuItem value)
     {
-        value = this.OfType<IBaseFolderMenuItem>()
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<IBaseFolderMenuItem>()
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.MailAccountId == accountId && b.SpecialFolderType == specialFolderType)) as FolderMenuItem;
 
         return value != null;
@@ -142,11 +170,12 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     public AccountMenuItem GetSpecificAccountMenuItem(Guid accountId)
     {
         AccountMenuItem accountMenuItem = null;
+        var rootItems = this.ToList();
 
-        accountMenuItem = this.OfType<AccountMenuItem>().FirstOrDefault(a => a.HoldingAccounts.Any(b => b.Id == accountId));
+        accountMenuItem = rootItems.OfType<AccountMenuItem>().FirstOrDefault(a => a.HoldingAccounts.Any(b => b.Id == accountId));
 
         // Look for the items inside the merged accounts if regular menu item is not found.
-        accountMenuItem ??= this.OfType<MergedAccountMenuItem>()
+        accountMenuItem ??= rootItems.OfType<MergedAccountMenuItem>()
             .FirstOrDefault(a => a.HoldingAccounts.Any(b => b.Id == accountId))?.SubMenuItems
             .OfType<AccountMenuItem>()
             .FirstOrDefault(a => a.AccountId == accountId);
@@ -167,7 +196,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     /// <param name="isEnabled">Whether menu items should be enabled or disabled.</param>
     public async Task SetAccountMenuItemEnabledStatusAsync(bool isEnabled)
     {
-        var accountItems = this.Where(a => a is IAccountMenuItem).Cast<IAccountMenuItem>();
+        var accountItems = this.Where(a => a is IAccountMenuItem).Cast<IAccountMenuItem>().ToList();
 
         await _dispatcher.ExecuteOnUIThread(() =>
         {
@@ -192,6 +221,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     {
         // Check root-level items.
         var rootItem = this.OfType<IBaseFolderMenuItem>()
+            .Where(a => a is not IMailCategoryMenuItem && a is not IMergedMailCategoryMenuItem)
             .FirstOrDefault(a => a.HandlingFolders.Any(b => b.Id == folderId));
 
         if (rootItem != null)
@@ -201,7 +231,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
         }
 
         // Check sub-items of root folders.
-        foreach (var rootFolder in this.OfType<IBaseFolderMenuItem>())
+        foreach (var rootFolder in this.OfType<IBaseFolderMenuItem>().ToList())
         {
             var subItem = rootFolder.SubMenuItems
                 .OfType<IBaseFolderMenuItem>()

Wino.Core.Domain/MenuItems/MergedMailCategoryMenuItem.cs

@@ -0,0 +1,44 @@
+using System.Collections.Generic;
+using System.Linq;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Entities.Shared;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Folders;
+
+namespace Wino.Core.Domain.MenuItems;
+
+public partial class MergedMailCategoryMenuItem : MenuItemBase<List<MailCategory>, IMenuItem>, IMergedAccountFolderMenuItem, IMergedMailCategoryMenuItem
+{
+    private readonly IReadOnlyList<IMailItemFolder> _handlingFolders;
+
+    [ObservableProperty]
+    private int unreadItemCount;
+
+    public MergedMailCategoryMenuItem(List<MailCategory> categories, IEnumerable<IMailItemFolder> handlingFolders, MergedInbox mergedInbox)
+        : base(categories, null, null)
+    {
+        _handlingFolders = handlingFolders?.ToList() ?? [];
+        MergedInbox = mergedInbox;
+    }
+
+    public string FolderName => Parameter.FirstOrDefault()?.Name ?? string.Empty;
+    public bool IsSynchronizationEnabled => false;
+    public SpecialFolderType SpecialFolderType => SpecialFolderType.Other;
+    public IEnumerable<IMailItemFolder> HandlingFolders => _handlingFolders;
+    public bool IsMoveTarget => true;
+    public bool IsSticky => false;
+    public bool IsSystemFolder => false;
+    public bool ShowUnreadCount => true;
+    public string AssignedAccountName => MergedInbox?.Name;
+    public MergedInbox MergedInbox { get; }
+    public string TextColorHex => Parameter.FirstOrDefault()?.TextColorHex;
+    public string BackgroundColorHex => Parameter.FirstOrDefault()?.BackgroundColorHex;
+    public bool HasTextColor => !string.IsNullOrWhiteSpace(TextColorHex);
+    public IReadOnlyList<MailCategory> Categories => Parameter;
+
+    public void UpdateFolder(IMailItemFolder folder)
+    {
+    }
+}

Wino.Core.Domain/Models/Accounts/AccountCreationDialogResult.cs

@@ -1,5 +1,10 @@
-using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Enums;
 
 namespace Wino.Core.Domain.Models.Accounts;
 
-public record AccountCreationDialogResult(MailProviderType ProviderType, string AccountName, SpecialImapProviderDetails SpecialImapProviderDetails, string AccountColorHex);
+public record AccountCreationDialogResult(
+    MailProviderType ProviderType,
+    string AccountName,
+    SpecialImapProviderDetails SpecialImapProviderDetails,
+    string AccountColorHex,
+    InitialSynchronizationRange InitialSynchronizationRange);

Wino.Core.Domain/Models/Accounts/InitialSynchronizationRangeOption.cs

@@ -0,0 +1,17 @@
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Core.Domain.Models.Accounts;
+
+public sealed class InitialSynchronizationRangeOption
+{
+    public InitialSynchronizationRange Range { get; }
+    public string DisplayText { get; }
+
+    public bool IsEverything => Range == InitialSynchronizationRange.Everything;
+
+    public InitialSynchronizationRangeOption(InitialSynchronizationRange range, string displayText)
+    {
+        Range = range;
+        DisplayText = displayText;
+    }
+}

Wino.Core.Domain/Models/Accounts/UnreadCategoryCountResult.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace Wino.Core.Domain.Models.Accounts;
+
+public class UnreadCategoryCountResult
+{
+    public Guid CategoryId { get; set; }
+    public Guid AccountId { get; set; }
+    public int UnreadItemCount { get; set; }
+}

Wino.Core.Domain/Models/Calendar/CalendarPageNavigationArgs.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 
 namespace Wino.Core.Domain.Models.Calendar;
 
@@ -18,4 +19,9 @@ public class CalendarPageNavigationArgs
     /// Force reloading the calendar data even when the target range does not change.
     /// </summary>
     public bool ForceReload { get; set; }
+
+    /// <summary>
+    /// Optional event target to navigate to after the calendar page loads the requested range.
+    /// </summary>
+    public CalendarItemTarget? PendingTarget { get; set; }
 }

Wino.Core.Domain/Models/Launch/MailShareRequest.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using Wino.Core.Domain.Models.Common;
+
+namespace Wino.Core.Domain.Models.Launch;
+
+public sealed class MailShareRequest
+{
+    public MailShareRequest(IReadOnlyList<SharedFile> files)
+    {
+        Files = files ?? throw new ArgumentNullException(nameof(files));
+    }
+
+    public IReadOnlyList<SharedFile> Files { get; }
+}

Wino.Core.Domain/Models/Launch/PendingComposeMailShareRequest.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Wino.Core.Domain.Models.Launch;
+
+public sealed class PendingComposeMailShareRequest
+{
+    public PendingComposeMailShareRequest(Guid draftUniqueId, MailShareRequest shareRequest)
+    {
+        DraftUniqueId = draftUniqueId;
+        ShareRequest = shareRequest ?? throw new ArgumentNullException(nameof(shareRequest));
+    }
+
+    public Guid DraftUniqueId { get; }
+    public MailShareRequest ShareRequest { get; }
+}

Wino.Core.Domain/Models/MailItem/MailCategoryColorOption.cs

@@ -0,0 +1,3 @@
+namespace Wino.Core.Domain.Models.MailItem;
+
+public sealed record MailCategoryColorOption(string BackgroundColorHex, string TextColorHex);

Wino.Core.Domain/Models/MailItem/MailCategoryDialogResult.cs

@@ -0,0 +1,3 @@
+namespace Wino.Core.Domain.Models.MailItem;
+
+public sealed record MailCategoryDialogResult(string Name, string BackgroundColorHex, string TextColorHex);

Wino.Core.Domain/Models/MailItem/MailCategoryPalette.cs

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+
+namespace Wino.Core.Domain.Models.MailItem;
+
+public static class MailCategoryPalette
+{
+    public static IReadOnlyList<MailCategoryColorOption> DefaultOptions { get; } =
+    [
+        new("#FEE2E2", "#991B1B"),
+        new("#FECACA", "#7F1D1D"),
+        new("#FFEDD5", "#9A3412"),
+        new("#FED7AA", "#7C2D12"),
+        new("#FEF3C7", "#92400E"),
+        new("#FDE68A", "#78350F"),
+        new("#ECFCCB", "#3F6212"),
+        new("#D9F99D", "#365314"),
+        new("#DCFCE7", "#166534"),
+        new("#BBF7D0", "#14532D"),
+        new("#CCFBF1", "#115E59"),
+        new("#99F6E4", "#134E4A"),
+        new("#CFFAFE", "#155E75"),
+        new("#A5F3FC", "#164E63"),
+        new("#DBEAFE", "#1D4ED8"),
+        new("#BFDBFE", "#1E3A8A"),
+        new("#E0E7FF", "#4338CA"),
+        new("#DDD6FE", "#5B21B6"),
+        new("#F3E8FF", "#7E22CE"),
+        new("#FCE7F3", "#9D174D")
+    ];
+}

Wino.Core.Domain/Models/MailItem/MailInsertPackage.cs

@@ -9,4 +9,5 @@ public record NewMailItemPackage(
     MailCopy Copy,
     MimeMessage Mime,
     string AssignedRemoteFolderId,
-    IReadOnlyList<AccountContact> ExtractedContacts = null);
+    IReadOnlyList<AccountContact> ExtractedContacts = null,
+    IReadOnlyList<string> CategoryNames = null);

Wino.Core.Domain/Models/MailItem/MailListInitializationOptions.cs

@@ -17,4 +17,8 @@ public record MailListInitializationOptions(IEnumerable<IMailItemFolder> Folders
                                             List<MailCopy> PreFetchMailCopies = null,
                                             bool DeduplicateByServerId = false,
                                             int Skip = 0,
-                                            int Take = 0);
+                                            int Take = 0)
+{
+    public IReadOnlyList<Guid> CategoryIds { get; init; }
+    public bool IsCategoryView => CategoryIds?.Count > 0;
+}

Wino.Core.Domain/Models/Requests/RequestBase.cs

@@ -35,6 +35,10 @@ public abstract record CalendarRequestBase(CalendarItem Item) : RequestBase<Cale
     public virtual Guid? LocalCalendarItemId => Item?.Id;
 }
 
+public abstract record CategoryRequestBase(Guid AccountId) : RequestBase<CategorySynchronizerOperation>, ICategoryActionRequest
+{
+}
+
 public class BatchCollection<TRequestType> : List<TRequestType>, IUIChangeRequest where TRequestType : IUIChangeRequest
 {
     public BatchCollection(IEnumerable<TRequestType> collection) : base(collection)

Wino.Core.Domain/Models/Settings/SettingsNavigationItemInfo.cs

@@ -68,6 +68,11 @@ public static class SettingsNavigationInfoProvider
                 Translator.SettingsMessageList_Description,
                 "\uE8C4",
                 searchKeywords: Translator.SettingsSearch_MessageList_Keywords),
+            new(WinoPage.MailNotificationSettingsPage,
+                Translator.SettingsMailNotifications_Title,
+                Translator.SettingsMailNotifications_Description,
+                "\uE7F4",
+                searchKeywords: Translator.SettingsSearch_MailNotifications_Keywords),
             new(WinoPage.ReadComposePanePage,
                 Translator.SettingsReadComposePane_Title,
                 Translator.SettingsReadComposePane_Description,
@@ -149,6 +154,7 @@ public static class SettingsNavigationInfoProvider
             WinoPage.PersonalizationPage => Translator.SettingsPersonalization_Title,
             WinoPage.AboutPage => Translator.SettingsAbout_Title,
             WinoPage.MessageListPage => Translator.SettingsMessageList_Title,
+            WinoPage.MailNotificationSettingsPage => Translator.SettingsMailNotifications_Title,
             WinoPage.ReadComposePanePage => Translator.SettingsReadComposePane_Title,
             WinoPage.AppPreferencesPage => Translator.SettingsAppPreferences_Title,
             WinoPage.CalendarSettingsPage => Translator.CalendarSettings_Preferences_Title,
@@ -170,6 +176,7 @@ public static class SettingsNavigationInfoProvider
             WinoPage.AccountDetailsPage => WinoPage.ManageAccountsPage,
             WinoPage.MergedAccountDetailsPage => WinoPage.ManageAccountsPage,
             WinoPage.AliasManagementPage => WinoPage.ManageAccountsPage,
+            WinoPage.MailCategoryManagementPage => WinoPage.ManageAccountsPage,
             WinoPage.SignatureManagementPage => WinoPage.ManageAccountsPage,
             WinoPage.ImapCalDavSettingsPage => WinoPage.ManageAccountsPage,
             WinoPage.CreateEmailTemplatePage => WinoPage.EmailTemplatesPage,

Wino.Core.Domain/Translations/en_US/resources.json

@@ -23,6 +23,14 @@
     "AccountCreationDialog_Initializing": "initializing",
     "AccountCreationDialog_PreparingFolders": "We are getting folder information at the moment.",
     "AccountCreationDialog_SigninIn": "Account information is being saved.",
+    "AccountCreation_InitialSynchronization_Title": "Mail synchronization range",
+    "AccountCreation_InitialSynchronization_Description": "Choose how far back Wino should download your mail during the first synchronization.",
+    "AccountCreation_InitialSynchronization_3Months": "3 Months",
+    "AccountCreation_InitialSynchronization_6Months": "6 Months",
+    "AccountCreation_InitialSynchronization_9Months": "9 Months",
+    "AccountCreation_InitialSynchronization_Year": "Year",
+    "AccountCreation_InitialSynchronization_Everything": "Everything",
+    "AccountCreation_InitialSynchronization_EverythingWarning": "This will synchronize all your mails to your computer. Extensive use of disk storage is needed. This is not recommended. For optimal performance use smaller synchronization timespan and use online search to access your mails.",
     "Purchased": "Purchased",
     "AccountEditDialog_Message": "Account Name",
     "AccountEditDialog_Title": "Edit Account",
@@ -37,6 +45,8 @@
     "AccountDetailsPage_TabMail": "Mail",
     "AccountDetailsPage_TabCalendar": "Calendar",
     "AccountDetailsPage_CalendarListDescription": "Select a calendar to configure its settings",
+    "AccountDetailsPage_InitialSynchronization_Title": "Initial synchronization",
+    "AccountDetailsPage_InitialSynchronization_Description": "Wino synchronized your mails until {0} going back.",
     "AddHyperlink": "Add",
     "AppCloseBackgroundSynchronizationWarningTitle": "Background Synchronization",
     "AppCloseStartupLaunchDisabledWarningMessageFirstLine": "Application has not been set to launch on Windows startup.",
@@ -57,6 +67,7 @@
     "BasicIMAPSetupDialog_Password": "Password",
     "BasicIMAPSetupDialog_Title": "IMAP Account",
     "Busy": "Busy",
+    "Buttons_Add": "Add",
     "Buttons_AddAccount": "Add Account",
     "Buttons_FixAccount": "Fix Account",
     "Buttons_AddNewAlias": "Add New Alias",
@@ -73,6 +84,7 @@
     "Buttons_Delete": "Delete",
     "Buttons_Deny": "Deny",
     "Buttons_Discard": "Discard",
+    "Buttons_Dismiss": "Dismiss",
     "Buttons_Edit": "Edit",
     "Buttons_EnableImageRendering": "Enable",
     "Buttons_Multiselect": "Select Multiple",
@@ -203,6 +215,8 @@
     "CalendarEventDetails_Organizer": "Organizer",
     "CalendarEventDetails_People": "People",
     "CalendarEventDetails_ReadOnlyEvent": "Read-only event",
+    "CalendarReadOnly_Title": "Read-only calendar",
+    "CalendarReadOnly_Message": "You can't update this calendar or its events. This calendar is read-only.",
     "CalendarContextMenu_Respond": "Respond",
     "CalendarEventDetails_Reminder": "Reminder",
     "CalendarReminder_StartedHoursAgo": "Started {0} hours ago",
@@ -797,6 +811,10 @@
     "SettingsConfigureSpecialFolders_Description": "Set folders with special functions. Folders such as Archive, Inbox, and Drafts are essential for Wino to function properly.",
     "SettingsConfigureSpecialFolders_Title": "Configure System Folders",
     "SettingsCustomTheme_Description": "Create your own custom theme with custom wallpaper and accent color.",
+    "SettingsCustomTheme_DeleteConfirm_Message": "Delete custom theme \"{0}\"? Its saved wallpaper will also be removed from disk.",
+    "SettingsCustomTheme_DeleteConfirm_Title": "Delete Theme",
+    "SettingsCustomTheme_DeleteMissing": "This custom theme no longer exists.",
+    "SettingsCustomTheme_DeleteSuccess": "Custom theme \"{0}\" was deleted.",
     "SettingsCustomTheme_Title": "Custom Theme",
     "SettingsDeleteAccount_Description": "Delete all e-mails and credentials associated with this account.",
     "SettingsDeleteAccount_Title": "Delete this account",
@@ -861,10 +879,28 @@
     "SettingsManageAccountSettings_Title": "Manage Accounts",
     "SettingsManageAliases_Description": "See e-mail aliases assigned for this account, update or delete them.",
     "SettingsManageAliases_Title": "Aliases",
+    "SettingsMailCategories_Description": "Manage synchronized and local categories for this account.",
+    "SettingsMailCategories_Title": "Categories",
     "SettingsEditAccountDetails_Title": "Edit Account Details",
     "SettingsEditAccountDetails_Description": "Change account name, sender name and assign a new color if you like.",
     "EditAccountDetailsPage_SaveSuccess_Title": "Changes Saved",
     "EditAccountDetailsPage_SaveSuccess_Message": "Your account details have been updated successfully.",
+    "MailCategoryManagementPage_Title": "Categories",
+    "MailCategoryManagementPage_Description": "Create, edit, delete, and favorite categories for this account.",
+    "MailCategoryManagementPage_Empty": "No categories yet.",
+    "MailCategoryManagementPage_DeleteConfirmationTitle": "Delete Category",
+    "MailCategoryManagementPage_DeleteConfirmationMessage": "Delete category \"{0}\"?",
+    "MailCategoryManagementPage_RefreshConfirmationMessage": "This will delete all your local categories, and re-synchronize everything from the server. Do you want to continue?",
+    "MailCategoryMenuItem": "Category",
+    "MailCategoryDialog_CreateTitle": "Create category",
+    "MailCategoryDialog_EditTitle": "Edit category",
+    "MailCategoryDialog_Name": "Name",
+    "MailCategoryDialog_NamePlaceholder": "Category name",
+    "MailCategoryDialog_Color": "Color",
+    "MailCategoryDialog_InvalidNameTitle": "Category name required",
+    "MailCategoryDialog_InvalidNameMessage": "Enter a category name to continue.",
+    "MailCategoryDialog_DuplicateTitle": "Category already exists",
+    "MailCategoryDialog_DuplicateMessage": "A category with the same name already exists for this account.",
     "SettingsManageLink_Description": "Move items to add new link or remove existing link.",
     "SettingsManageLink_Title": "Manage Link",
     "SettingsMarkAsRead_Description": "Change what should happen to the selected item.",
@@ -875,6 +911,14 @@
     "SettingsMarkAsRead_WhenSelected": "When selected",
     "SettingsMessageList_Description": "Change how your messages should be organized in mail list.",
     "SettingsMessageList_Title": "Message List",
+    "SettingsMailNotifications_Title": "Notifications",
+    "SettingsMailNotifications_Description": "Notification settings and preferences for mails.",
+    "SettingsMailNotifications_Actions_Title": "App notification actions.",
+    "SettingsMailNotifications_Actions_Description": "Customize the button behaviors on the notifications as you like.",
+    "SettingsMailNotifications_FirstAction_Title": "First notification action",
+    "SettingsMailNotifications_FirstAction_Description": "Choose the first button shown on mail notifications.",
+    "SettingsMailNotifications_SecondAction_Title": "Second notification action",
+    "SettingsMailNotifications_SecondAction_Description": "Choose the second button shown on mail notifications.",
     "SettingsNoAccountSetupMessage": "You didn't setup any accounts yet.",
     "SettingsNotifications_Description": "Turn on or off notifications for this account.",
     "SettingsNotifications_Title": "Notifications",
@@ -911,6 +955,7 @@
     "SettingsSearch_About_Keywords": "about;version;website;privacy;github;donate;store;support",
     "SettingsSearch_KeyboardShortcuts_Keywords": "shortcut;shortcuts;hotkey;hotkeys;keyboard;keys",
     "SettingsSearch_MessageList_Keywords": "message;messages;list;threading;threads;avatar;preview;sender",
+    "SettingsSearch_MailNotifications_Keywords": "mail;notification;notifications;toast;action;actions;reply;reply all;forward;archive;delete;junk;read",
     "SettingsSearch_ReadComposePane_Keywords": "reader;compose;composer;font;fonts;external content;display;reading",
     "SettingsSearch_SignatureAndEncryption_Keywords": "signature;signatures;encryption;certificate;certificates;s mime;smime;security",
     "SettingsSearch_Storage_Keywords": "storage;cache;caching;mime;disk;space;cleanup;clean up;local data",
@@ -1477,11 +1522,13 @@
     "AccountSetup_Step_TestingCalendarAuth": "Testing calendar authentication",
     "AccountSetup_Step_SavingAccount": "Saving account information",
     "AccountSetup_Step_FetchingCalendarMetadata": "Fetching calendar metadata",
+    "AccountSetup_Step_SyncingCategories": "Synchronizing categories",
     "AccountSetup_Step_SyncingAliases": "Synchronizing aliases",
     "AccountSetup_Step_Finalizing": "Finalizing setup",
     "AccountSetup_FailureMessage": "Setup failed. Go back to fix your settings, or try again later.",
     "AccountSetup_SuccessMessage": "Your account has been set up successfully!",
     "AccountSetup_GoBackButton": "Go Back",
     "AccountSetup_TryAgainButton": "Try Again",
+    "Exception_FailedToSynchronizeCategories": "Failed to synchronize categories",
     "ImapCalDavSettings_AutoDiscoveryFailed": "Auto-discovery failed. Please enter settings manually in the Advanced tab."
 }

Wino.Core.Tests/Services/MailFetchingTests.cs

@@ -510,7 +510,8 @@ public class MailFetchingTests : IAsyncLifetime
             preferencesService.Object,
             contactPictureFileService.Object);
 
-        var folderService = new FolderService(db, accountService);
+        var mailCategoryService = new MailCategoryService(db);
+        var folderService = new FolderService(db, accountService, mailCategoryService);
         var contactService = new ContactService(db);
         var sentMailReceiptService = new SentMailReceiptService(db, folderService, accountService);
 
@@ -522,6 +523,7 @@ public class MailFetchingTests : IAsyncLifetime
             signatureService.Object,
             mimeFileService.Object,
             preferencesService.Object,
-            sentMailReceiptService);
+            sentMailReceiptService,
+            mailCategoryService);
     }
 }

Wino.Core.Tests/Services/MailThreadingTests.cs

@@ -269,7 +269,8 @@ public class MailThreadingTests : IAsyncLifetime
             preferencesService.Object,
             contactPictureFileService.Object);
 
-        var folderService = new FolderService(db, accountService);
+        var mailCategoryService = new MailCategoryService(db);
+        var folderService = new FolderService(db, accountService, mailCategoryService);
         var contactService = new ContactService(db);
         var sentMailReceiptService = new SentMailReceiptService(db, folderService, accountService);
 
@@ -281,6 +282,7 @@ public class MailThreadingTests : IAsyncLifetime
             signatureService.Object,
             mimeFileService.Object,
             preferencesService.Object,
-            sentMailReceiptService);
+            sentMailReceiptService,
+            mailCategoryService);
     }
 }

Wino.Core.Tests/Synchronizers/OutlookSynchronizerRequestSuccessTests.cs

@@ -70,8 +70,9 @@ public sealed class OutlookSynchronizerRequestSuccessTests
 
         var authenticator = new Mock<IAuthenticator>(MockBehavior.Loose);
         var errorFactory = new Mock<IOutlookSynchronizerErrorHandlerFactory>(MockBehavior.Loose);
+        var mailCategoryService = new Mock<IMailCategoryService>(MockBehavior.Loose);
 
-        return new OutlookSynchronizer(account, authenticator.Object, changeProcessor, errorFactory.Object);
+        return new OutlookSynchronizer(account, authenticator.Object, changeProcessor, errorFactory.Object, mailCategoryService.Object);
     }
 
     private static MailCopy CreateMailCopy() =>

Wino.Core.ViewModels/PersonalizationPageViewModel.cs

@@ -174,8 +174,46 @@ public partial class PersonalizationPageViewModel : CoreBaseViewModel
         }
     }
 
+    [RelayCommand]
+    private async Task DeleteCustomThemeAsync(AppThemeBase theme)
+    {
+        if (theme == null || theme.AppThemeType != AppThemeType.Custom)
+        {
+            return;
+        }
+
+        var shouldDelete = await _dialogService.ShowConfirmationDialogAsync(
+            string.Format(Translator.SettingsCustomTheme_DeleteConfirm_Message, theme.ThemeName),
+            Translator.SettingsCustomTheme_DeleteConfirm_Title,
+            Translator.Buttons_Delete);
+
+        if (!shouldDelete)
+        {
+            return;
+        }
+
+        var isDeleted = await _newThemeService.DeleteCustomThemeAsync(theme.Id);
+
+        if (!isDeleted)
+        {
+            _dialogService.InfoBarMessage(
+                Translator.GeneralTitle_Warning,
+                Translator.SettingsCustomTheme_DeleteMissing,
+                InfoBarMessageType.Warning);
+            return;
+        }
+
+        await InitializeSettingsAsync();
+
+        _dialogService.InfoBarMessage(
+            Translator.GeneralTitle_Info,
+            string.Format(Translator.SettingsCustomTheme_DeleteSuccess, theme.ThemeName),
+            InfoBarMessageType.Success);
+    }
+
     private void InitializeColors()
     {
+        Colors.Clear();
         Colors.Add(new AppColorViewModel("#0078d7"));
         Colors.Add(new AppColorViewModel("#00838c"));
         Colors.Add(new AppColorViewModel("#e3008c"));

Wino.Core/Extensions/GoogleIntegratorExtensions.cs

@@ -14,27 +14,32 @@ namespace Wino.Core.Extensions;
 
 public static class GoogleIntegratorExtensions
 {
-    private static string GetNormalizedLabelName(string labelName)
+    private static bool TryGetKnownFolderLabelName(string labelName, out string normalizedLabelName)
     {
-        // 1. Remove CATEGORY_ prefix.
-        var normalizedLabelName = labelName.Replace(ServiceConstants.CATEGORY_PREFIX, string.Empty);
+        normalizedLabelName = string.Empty;
 
-        // 2. Normalize label name by capitalizing first letter.
-        normalizedLabelName = char.ToUpper(normalizedLabelName[0]) + normalizedLabelName.Substring(1).ToLower();
+        if (string.IsNullOrEmpty(labelName))
+            return false;
 
-        return normalizedLabelName;
+        var knownFolderKey = labelName.Replace(ServiceConstants.CATEGORY_PREFIX, string.Empty);
+
+        if (!ServiceConstants.KnownFolderDictionary.ContainsKey(knownFolderKey))
+            return false;
+
+        normalizedLabelName = char.ToUpper(knownFolderKey[0]) + knownFolderKey.Substring(1).ToLower();
+
+        return true;
     }
 
     public static MailItemFolder GetLocalFolder(this Label label, ListLabelsResponse labelsResponse, Guid accountId)
     {
-        var normalizedLabelName = GetFolderName(label.Name);
+        var folderName = GetFolderName(label.Name);
 
-        // Even though we normalize the label name, check is done by capitalizing the label name.
-        var capitalNormalizedLabelName = normalizedLabelName.ToUpper();
+        var lookupLabelName = GetLookupLabelName(label.Name);
 
-        bool isSpecialFolder = ServiceConstants.KnownFolderDictionary.ContainsKey(capitalNormalizedLabelName);
+        bool isSpecialFolder = ServiceConstants.KnownFolderDictionary.ContainsKey(lookupLabelName);
 
-        var specialFolderType = isSpecialFolder ? ServiceConstants.KnownFolderDictionary[capitalNormalizedLabelName] : SpecialFolderType.Other;
+        var specialFolderType = isSpecialFolder ? ServiceConstants.KnownFolderDictionary[lookupLabelName] : SpecialFolderType.Other;
 
         // We used to support FOLDER_HIDE_IDENTIFIER to hide invisible folders.
         // However, a lot of people complained that they don't see their folders after the initial sync
@@ -59,7 +64,7 @@ public static class GoogleIntegratorExtensions
         {
             TextColorHex = label.Color?.TextColor,
             BackgroundColorHex = label.Color?.BackgroundColor,
-            FolderName = normalizedLabelName,
+            FolderName = folderName,
             RemoteFolderId = label.Id,
             Id = Guid.NewGuid(),
             MailAccountId = accountId,
@@ -104,7 +109,29 @@ public static class GoogleIntegratorExtensions
         return labelsResponse.Labels.FirstOrDefault(a => a.Name == parentLabelName)?.Id ?? string.Empty;
     }
 
+    public static string GetLookupLabelName(string fullFolderName)
+    {
+        var folderName = GetLastFolderName(fullFolderName);
+
+        if (string.IsNullOrEmpty(folderName))
+            return string.Empty;
+
+        return folderName.Replace(ServiceConstants.CATEGORY_PREFIX, string.Empty);
+    }
+
     public static string GetFolderName(string fullFolderName)
+    {
+        var lastPart = GetLastFolderName(fullFolderName);
+
+        if (string.IsNullOrEmpty(lastPart))
+            return string.Empty;
+
+        return TryGetKnownFolderLabelName(lastPart, out var normalizedLabelName)
+            ? normalizedLabelName
+            : lastPart;
+    }
+
+    private static string GetLastFolderName(string fullFolderName)
     {
         if (string.IsNullOrEmpty(fullFolderName)) return string.Empty;
 
@@ -113,9 +140,7 @@ public static class GoogleIntegratorExtensions
 
         string[] parts = fullFolderName.Split(ServiceConstants.FOLDER_SEPERATOR_CHAR);
 
-        var lastPart = parts[parts.Length - 1];
-
-        return GetNormalizedLabelName(lastPart);
+        return parts[parts.Length - 1];
     }
 
     public static List<RemoteAccountAlias> GetRemoteAliases(this ListSendAsResponse response)
@@ -145,6 +170,8 @@ public static class GoogleIntegratorExtensions
             Id = Guid.NewGuid(),
             TimeZone = calendarListEntry.TimeZone,
             IsPrimary = calendarListEntry.Primary.GetValueOrDefault(),
+            IsReadOnly = !string.Equals(calendarListEntry.AccessRole, "owner", StringComparison.OrdinalIgnoreCase)
+                         && !string.Equals(calendarListEntry.AccessRole, "writer", StringComparison.OrdinalIgnoreCase),
             IsSynchronizationEnabled = true,
         };
 

Wino.Core/Extensions/OutlookIntegratorExtensions.cs

@@ -190,6 +190,7 @@ public static class OutlookIntegratorExtensions
             Id = Guid.NewGuid(),
             RemoteCalendarId = outlookCalendar.Id,
             IsPrimary = outlookCalendar.IsDefaultCalendar.GetValueOrDefault(),
+            IsReadOnly = !outlookCalendar.CanEdit.GetValueOrDefault(true),
             Name = outlookCalendar.Name,
             IsSynchronizationEnabled = true,
             IsExtended = true,

Wino.Core/Requests/Category/MailCategoryCreateRequest.cs

@@ -0,0 +1,10 @@
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Category;
+
+public record MailCategoryCreateRequest(MailCategory Category) : CategoryRequestBase(Category.MailAccountId)
+{
+    public override CategorySynchronizerOperation Operation => CategorySynchronizerOperation.CreateCategory;
+}

Wino.Core/Requests/Category/MailCategoryDeleteRequest.cs

@@ -0,0 +1,14 @@
+using System.Collections.Generic;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Category;
+
+public record MailCategoryDeleteRequest(
+    MailCategory Category,
+    string PreviousRemoteId,
+    IReadOnlyList<MailCategoryMessageUpdateTarget> AffectedMessages = null) : CategoryRequestBase(Category.MailAccountId)
+{
+    public override CategorySynchronizerOperation Operation => CategorySynchronizerOperation.DeleteCategory;
+}

Wino.Core/Requests/Category/MailCategoryRequestModels.cs

@@ -0,0 +1,5 @@
+using System.Collections.Generic;
+
+namespace Wino.Core.Requests.Category;
+
+public sealed record MailCategoryMessageUpdateTarget(string MessageId, IReadOnlyList<string> CategoryNames);

Wino.Core/Requests/Category/MailCategoryUpdateRequest.cs

@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Category;
+
+public record MailCategoryUpdateRequest(
+    MailCategory Category,
+    string PreviousName,
+    string PreviousRemoteId,
+    IReadOnlyList<MailCategoryMessageUpdateTarget> AffectedMessages = null) : CategoryRequestBase(Category.MailAccountId)
+{
+    public override CategorySynchronizerOperation Operation => CategorySynchronizerOperation.UpdateCategory;
+}

Wino.Core/Requests/Mail/MailCategoryAssignmentRequest.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Mail;
+
+public record MailCategoryAssignmentRequest(
+    MailCopy Item,
+    Guid MailCategoryId,
+    string CategoryName,
+    IReadOnlyList<string> CategoryNames,
+    bool IsAssigned) : MailRequestBase(Item), ICustomFolderSynchronizationRequest
+{
+    public override MailSynchronizerOperation Operation => MailSynchronizerOperation.UpdateCategories;
+    public List<Guid> SynchronizationFolderIds => [Item.FolderId];
+    public bool ExcludeMustHaveFolders => true;
+}
+
+public class BatchMailCategoryAssignmentRequest : BatchCollection<MailCategoryAssignmentRequest>
+{
+    public BatchMailCategoryAssignmentRequest(IEnumerable<MailCategoryAssignmentRequest> collection) : base(collection)
+    {
+    }
+}

Wino.Core/Services/SynchronizationManager.cs

@@ -370,6 +370,26 @@ public class SynchronizationManager : ISynchronizationManager, IRecipient<Accoun
         return await SynchronizeMailAsync(options, cancellationToken);
     }
 
+    /// <summary>
+    /// Handles category synchronization for the given account.
+    /// </summary>
+    /// <param name="accountId">Account ID to synchronize categories for</param>
+    /// <param name="cancellationToken">Cancellation token</param>
+    /// <returns>Synchronization result</returns>
+    public async Task<MailSynchronizationResult> SynchronizeCategoriesAsync(Guid accountId,
+                                                                            CancellationToken cancellationToken = default)
+    {
+        EnsureInitialized();
+
+        var options = new MailSynchronizationOptions
+        {
+            AccountId = accountId,
+            Type = MailSynchronizationType.Categories
+        };
+
+        return await SynchronizeMailAsync(options, cancellationToken);
+    }
+
     /// <summary>
     /// Handles profile synchronization for the given account.
     /// </summary>

Wino.Core/Services/SynchronizerFactory.cs

@@ -26,6 +26,7 @@ public class SynchronizerFactory : ISynchronizerFactory
     private readonly ICalDavClient _calDavClient;
     private readonly IAutoDiscoveryService _autoDiscoveryService;
     private readonly ICalendarService _calendarService;
+    private readonly IMailCategoryService _mailCategoryService;
 
     private readonly List<IWinoSynchronizerBase> synchronizerCache = new();
 
@@ -41,7 +42,8 @@ public class SynchronizerFactory : ISynchronizerFactory
                                UnifiedImapSynchronizer unifiedImapSynchronizer,
                                ICalDavClient calDavClient,
                                IAutoDiscoveryService autoDiscoveryService,
-                               ICalendarService calendarService)
+                               ICalendarService calendarService,
+                               IMailCategoryService mailCategoryService)
     {
         _outlookChangeProcessor = outlookChangeProcessor;
         _gmailChangeProcessor = gmailChangeProcessor;
@@ -56,6 +58,7 @@ public class SynchronizerFactory : ISynchronizerFactory
         _calDavClient = calDavClient;
         _autoDiscoveryService = autoDiscoveryService;
         _calendarService = calendarService;
+        _mailCategoryService = mailCategoryService;
     }
 
     public async Task<IWinoSynchronizerBase> GetAccountSynchronizerAsync(Guid accountId)
@@ -86,7 +89,7 @@ public class SynchronizerFactory : ISynchronizerFactory
         {
             case Domain.Enums.MailProviderType.Outlook:
                 var outlookAuthenticator = _authenticationProvider.GetAuthenticator(Domain.Enums.MailProviderType.Outlook) as IOutlookAuthenticator;
-                return new OutlookSynchronizer(mailAccount, outlookAuthenticator, _outlookChangeProcessor, _outlookSynchronizerErrorHandlerFactory);
+                return new OutlookSynchronizer(mailAccount, outlookAuthenticator, _outlookChangeProcessor, _outlookSynchronizerErrorHandlerFactory, _mailCategoryService);
             case Domain.Enums.MailProviderType.Gmail:
                 var gmailAuthenticator = _authenticationProvider.GetAuthenticator(Domain.Enums.MailProviderType.Gmail) as IGmailAuthenticator;
                 return new GmailSynchronizer(mailAccount, gmailAuthenticator, _gmailChangeProcessor, _gmailSynchronizerErrorHandlerFactory);

Wino.Core/Services/WinoRequestDelegator.cs

@@ -165,6 +165,13 @@ public class WinoRequestDelegator : IWinoRequestDelegator
         if (calendarPreparationRequest == null)
             return;
 
+        var resolvedCalendar = await ResolveCalendarAsync(calendarPreparationRequest).ConfigureAwait(false);
+        if (resolvedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         IRequestBase request = calendarPreparationRequest.Operation switch
         {
             CalendarSynchronizerOperation.CreateEvent => await CreateCalendarEventRequestAsync(calendarPreparationRequest).ConfigureAwait(false),
@@ -200,6 +207,21 @@ public class WinoRequestDelegator : IWinoRequestDelegator
         await QueueCalendarSynchronizationAsync(accountId);
     }
 
+    public async Task ExecuteAsync(Guid accountId, IEnumerable<IRequestBase> requests)
+    {
+        var requestList = requests?.Where(a => a != null).ToList() ?? [];
+        if (requestList.Count == 0)
+            return;
+
+        foreach (var request in requestList)
+        {
+            await QueueRequestAsync(request, accountId).ConfigureAwait(false);
+        }
+
+        await SendSyncActionsAddedAsync(requestList, accountId).ConfigureAwait(false);
+        await QueueSynchronizationAsync(accountId).ConfigureAwait(false);
+    }
+
     private async Task<IRequestBase> CreateCalendarEventRequestAsync(CalendarOperationPreparationRequest calendarPreparationRequest)
     {
         var composeResult = calendarPreparationRequest.ComposeResult
@@ -212,6 +234,25 @@ public class WinoRequestDelegator : IWinoRequestDelegator
         return new CreateCalendarEventRequest(composeResult, assignedCalendar);
     }
 
+    private async Task<AccountCalendar> ResolveCalendarAsync(CalendarOperationPreparationRequest calendarPreparationRequest)
+    {
+        if (calendarPreparationRequest.Operation == CalendarSynchronizerOperation.CreateEvent)
+        {
+            var calendarId = calendarPreparationRequest.ComposeResult?.CalendarId ?? Guid.Empty;
+            return calendarId == Guid.Empty
+                ? null
+                : await _calendarService.GetAccountCalendarAsync(calendarId).ConfigureAwait(false);
+        }
+
+        if (calendarPreparationRequest.CalendarItem?.AssignedCalendar is AccountCalendar assignedCalendar)
+            return assignedCalendar;
+
+        var fallbackCalendarId = calendarPreparationRequest.CalendarItem?.CalendarId ?? Guid.Empty;
+        return fallbackCalendarId == Guid.Empty
+            ? null
+            : await _calendarService.GetAccountCalendarAsync(fallbackCalendarId).ConfigureAwait(false);
+    }
+
     private IRequestBase CreateDeclineRequest(CalendarItem calendarItem, string responseMessage)
     {
         // For Outlook accounts, declined events are deleted by the server after synchronization.

Wino.Core/Synchronizers/GmailSynchronizer.cs

@@ -81,9 +81,8 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
     public override uint BatchModificationSize => 1000;
 
     /// <summary>
-    /// Maximum messages to fetch per folder during initial sync (1500).
-    /// All messages are downloaded with METADATA ONLY - no raw MIME content.
-    /// Uses Gmail API's Metadata format which includes headers, labels, and snippet but NOT full message body.
+    /// Legacy page size hint kept for compatibility with shared synchronizer contracts.
+    /// Gmail initial sync now downloads all messages inside the selected cutoff window.
     /// </summary>
     public override uint InitialMessageDownloadCountPerFolder => 1500;
 
@@ -304,13 +303,18 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
 
     /// <summary>
     /// Performs initial synchronization by downloading messages per-folder.
-    /// Each folder gets up to 1500 messages, but we track already downloaded message IDs globally
-    /// to avoid downloading the same message multiple times (Gmail messages can have multiple labels).
+    /// Messages are filtered by the account's configured initial synchronization cutoff date when present,
+    /// and duplicates are avoided globally because Gmail messages can have multiple labels.
     /// </summary>
     private async Task<List<string>> PerformInitialSyncAsync(CancellationToken cancellationToken)
     {
         // Track all downloaded message IDs globally to avoid duplicate downloads
         var downloadedMessageIds = new HashSet<string>();
+        var referenceDateUtc = Account.CreatedAt ?? DateTime.UtcNow;
+        var initialSynchronizationCutoffDateUtc = Account.InitialSynchronizationRange.ToCutoffDateUtc(referenceDateUtc);
+        var queryText = initialSynchronizationCutoffDateUtc.HasValue
+            ? $"after:{initialSynchronizationCutoffDateUtc.Value.ToUniversalTime():yyyy/MM/dd}"
+            : null;
 
         _logger.Information("Performing initial sync for {Name} - downloading messages per folder", Account.Name);
 
@@ -337,7 +341,6 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
 
                 var folderDownloaded = 0;
                 string pageToken = null;
-                var remainingToDownload = (int)InitialMessageDownloadCountPerFolder;
 
                 do
                 {
@@ -345,8 +348,9 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
 
                     var request = _gmailService.Users.Messages.List("me");
                     request.LabelIds = new Google.Apis.Util.Repeatable<string>(new[] { folder.RemoteFolderId });
-                    request.MaxResults = Math.Min(remainingToDownload, 500); // API max is 500
+                    request.MaxResults = 500; // API max is 500
                     request.PageToken = pageToken;
+                    request.Q = queryText;
 
                     var response = await request.ExecuteAsync(cancellationToken);
 
@@ -373,19 +377,12 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
                             totalMessagesDownloaded += newMessageIds.Count;
                         }
 
-                        // Count all messages (including duplicates) toward the folder limit
-                        remainingToDownload -= response.Messages.Count;
-
                         _logger.Debug("Folder {FolderName}: Downloaded {New} new messages ({Total} total in folder)",
                             folder.FolderName, newMessageIds.Count, folderDownloaded);
                     }
 
                     pageToken = response.NextPageToken;
 
-                    // Stop if we've processed enough messages for this folder or no more pages
-                    if (remainingToDownload <= 0 || string.IsNullOrEmpty(pageToken))
-                        break;
-
                 } while (!string.IsNullOrEmpty(pageToken));
 
                 _logger.Information("Folder {FolderName}: Downloaded {Count} messages", folder.FolderName, folderDownloaded);
@@ -762,6 +759,8 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
                     existingLocalCalendar.BackgroundColorHex = resolvedColor;
                     existingLocalCalendar.TextColorHex = ColorHelpers.GetReadableTextColorHex(existingLocalCalendar.BackgroundColorHex);
                     existingLocalCalendar.IsPrimary = string.Equals(existingLocalCalendar.RemoteCalendarId, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+                    existingLocalCalendar.IsReadOnly = !string.Equals(calendar.AccessRole, "owner", StringComparison.OrdinalIgnoreCase)
+                                                      && !string.Equals(calendar.AccessRole, "writer", StringComparison.OrdinalIgnoreCase);
 
                     updatedCalendars.Add(existingLocalCalendar);
                 }
@@ -905,7 +904,7 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
 
                 if (ShouldUpdateFolder(remoteFolder, existingLocalFolder))
                 {
-                    existingLocalFolder.FolderName = remoteFolder.Name;
+                    existingLocalFolder.FolderName = GoogleIntegratorExtensions.GetFolderName(remoteFolder.Name);
                     existingLocalFolder.TextColorHex = remoteFolder.Color?.TextColor;
                     existingLocalFolder.BackgroundColorHex = remoteFolder.Color?.BackgroundColor;
 
@@ -943,14 +942,17 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
         var remoteBackgroundColor = ResolveSynchronizedCalendarBackgroundColor(GetRemoteGmailCalendarBackgroundColor(calendarListEntry), accountCalendar);
         var remoteTextColor = ColorHelpers.GetReadableTextColorHex(remoteBackgroundColor);
         var remoteIsPrimary = string.Equals(calendarListEntry.Id, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+        var remoteIsReadOnly = !string.Equals(calendarListEntry.AccessRole, "owner", StringComparison.OrdinalIgnoreCase)
+                               && !string.Equals(calendarListEntry.AccessRole, "writer", StringComparison.OrdinalIgnoreCase);
 
         bool isNameChanged = !string.Equals(accountCalendar.Name, remoteCalendarName, StringComparison.OrdinalIgnoreCase);
         bool isTimeZoneChanged = !string.Equals(accountCalendar.TimeZone, remoteTimeZone, StringComparison.OrdinalIgnoreCase);
         bool isBackgroundColorChanged = !string.Equals(accountCalendar.BackgroundColorHex, remoteBackgroundColor, StringComparison.OrdinalIgnoreCase);
         bool isTextColorChanged = !string.Equals(accountCalendar.TextColorHex, remoteTextColor, StringComparison.OrdinalIgnoreCase);
         bool isPrimaryChanged = accountCalendar.IsPrimary != remoteIsPrimary;
+        bool isReadOnlyChanged = accountCalendar.IsReadOnly != remoteIsReadOnly;
 
-        return isNameChanged || isTimeZoneChanged || isBackgroundColorChanged || isTextColorChanged || isPrimaryChanged;
+        return isNameChanged || isTimeZoneChanged || isBackgroundColorChanged || isTextColorChanged || isPrimaryChanged || isReadOnlyChanged;
     }
 
     private static string GetRemoteGmailCalendarBackgroundColor(CalendarListEntry calendarListEntry)
@@ -996,9 +998,9 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
     private bool ShouldUpdateFolder(Label remoteFolder, MailItemFolder existingLocalFolder)
     {
         var remoteFolderName = GoogleIntegratorExtensions.GetFolderName(remoteFolder.Name);
-        var localFolderName = GoogleIntegratorExtensions.GetFolderName(existingLocalFolder.FolderName);
+        var localFolderName = existingLocalFolder.FolderName ?? string.Empty;
 
-        bool isNameChanged = !localFolderName.Equals(remoteFolderName, StringComparison.OrdinalIgnoreCase);
+        bool isNameChanged = !localFolderName.Equals(remoteFolderName, StringComparison.Ordinal);
         bool isColorChanged = existingLocalFolder.BackgroundColorHex != remoteFolder.Color?.BackgroundColor ||
                 existingLocalFolder.TextColorHex != remoteFolder.Color?.TextColor;
 

Wino.Core/Synchronizers/ImapSync/UnifiedImapSynchronizer.cs

@@ -9,6 +9,7 @@ using MailKit.Search;
 using MoreLinq;
 using Serilog;
 using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Extensions;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.MailItem;
@@ -252,9 +253,20 @@ public class UnifiedImapSynchronizer
                 .OpenAsync(FolderAccess.ReadOnly, folder.UidValidity, localHighestModSeq, knownUidStructs, cancellationToken)
                 .ConfigureAwait(false);
 
-            var changedUids = await remoteFolder
-                .SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken)
-                .ConfigureAwait(false);
+            IList<UniqueId> changedUids;
+
+            if (folder.HighestModeSeq == 0)
+            {
+                changedUids = await remoteFolder
+                    .SearchAsync(BuildInitialSyncQuery(synchronizer), cancellationToken)
+                    .ConfigureAwait(false);
+            }
+            else
+            {
+                changedUids = await remoteFolder
+                    .SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken)
+                    .ConfigureAwait(false);
+            }
 
             downloadedMessageIds = await DownloadMessagesByUidsAsync(client, remoteFolder, folder, changedUids, synchronizer, cancellationToken).ConfigureAwait(false);
 
@@ -308,25 +320,26 @@ public class UnifiedImapSynchronizer
             {
                 IList<UniqueId> changedUids;
 
-                if (client.Capabilities.HasFlag(ImapCapabilities.Sort))
+                if (isInitialSync)
                 {
                     changedUids = await remoteFolder
-                        .SortAsync(SearchQuery.ChangedSince(localHighestModSeq), [OrderBy.ReverseDate], cancellationToken)
+                        .SearchAsync(BuildInitialSyncQuery(synchronizer), cancellationToken)
                         .ConfigureAwait(false);
                 }
                 else
                 {
-                    changedUids = await remoteFolder
-                        .SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken)
-                        .ConfigureAwait(false);
-                }
-
-                if (isInitialSync)
-                {
-                    changedUids = changedUids
-                        .OrderByDescending(a => a.Id)
-                        .Take((int)synchronizer.InitialMessageDownloadCountPerFolder)
-                        .ToList();
+                    if (client.Capabilities.HasFlag(ImapCapabilities.Sort))
+                    {
+                        changedUids = await remoteFolder
+                            .SortAsync(SearchQuery.ChangedSince(localHighestModSeq), [OrderBy.ReverseDate], cancellationToken)
+                            .ConfigureAwait(false);
+                    }
+                    else
+                    {
+                        changedUids = await remoteFolder
+                            .SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken)
+                            .ConfigureAwait(false);
+                    }
                 }
 
                 downloadedMessageIds = await DownloadMessagesByUidsAsync(client, remoteFolder, folder, changedUids, synchronizer, cancellationToken).ConfigureAwait(false);
@@ -367,15 +380,12 @@ public class UnifiedImapSynchronizer
 
             if (folder.HighestKnownUid == 0)
             {
-                var remoteUids = await remoteFolder.SearchAsync(SearchQuery.All, cancellationToken).ConfigureAwait(false);
-
-                var initialUids = remoteUids
-                    .OrderByDescending(a => a.Id)
-                    .Take((int)synchronizer.InitialMessageDownloadCountPerFolder)
-                    .ToList();
+                var initialUids = await remoteFolder
+                    .SearchAsync(BuildInitialSyncQuery(synchronizer), cancellationToken)
+                    .ConfigureAwait(false);
 
                 downloadedMessageIds = await DownloadMessagesByUidsAsync(client, remoteFolder, folder, initialUids, synchronizer, cancellationToken).ConfigureAwait(false);
-                UpdateHighestKnownUid(folder, remoteFolder, remoteUids.Select(a => a.Id));
+                UpdateHighestKnownUid(folder, remoteFolder, initialUids.Select(a => a.Id));
             }
             else
             {
@@ -410,6 +420,22 @@ public class UnifiedImapSynchronizer
 
     #region Shared Helpers
 
+    private static SearchQuery BuildInitialSyncQuery(IImapSynchronizer synchronizer)
+    {
+        if (synchronizer is IBaseSynchronizer { Account: { } account })
+        {
+            var referenceDateUtc = account.CreatedAt ?? DateTime.UtcNow;
+            var cutoffDateUtc = account.InitialSynchronizationRange.ToCutoffDateUtc(referenceDateUtc);
+
+            if (cutoffDateUtc.HasValue)
+            {
+                return SearchQuery.DeliveredAfter(cutoffDateUtc.Value.ToUniversalTime().Date);
+            }
+        }
+
+        return SearchQuery.All;
+    }
+
     private async Task EnsureUidValidityStateAsync(MailItemFolder folder, IMailFolder remoteFolder)
     {
         if (folder.UidValidity != 0 && remoteFolder.UidValidity != folder.UidValidity)

Wino.Core/Synchronizers/OutlookSynchronizer.cs

@@ -41,6 +41,7 @@ using Wino.Core.Integration.Processors;
 using Wino.Core.Misc;
 using Wino.Core.Requests.Bundles;
 using Wino.Core.Requests.Calendar;
+using Wino.Core.Requests.Category;
 using Wino.Core.Requests.Folder;
 using Wino.Core.Requests.Mail;
 using Wino.Messaging.UI;
@@ -55,14 +56,14 @@ public partial class OutlookSynchronizerJsonContext : JsonSerializerContext;
 /// 
 /// SYNCHRONIZATION STRATEGY:
 /// - Uses delta API for both initial and incremental sync
-/// - Initial sync: Downloads last 30 days of emails with metadata only
+/// - Initial sync: Downloads messages using the account's configured cutoff date with metadata only
 /// - Incremental sync: Uses delta token to get only changes since last sync
 /// - Messages are downloaded with metadata only (no MIME content during sync)
 /// - MIME files are downloaded on-demand when user explicitly reads a message
 /// 
 /// Key implementation details:
 /// - SynchronizeFolderAsync: Main entry point for per-folder synchronization
-/// - DownloadMailsForInitialSyncAsync: Downloads last 30 days using delta API with filter
+/// - DownloadMailsForInitialSyncAsync: Downloads messages using delta API with an optional cutoff filter
 /// - ProcessDeltaChangesAsync: Processes incremental changes using delta token
 /// - DownloadMessageMetadataBatchAsync: Downloads metadata in batches using Graph batch API
 /// - CreateMailCopyFromMessageAsync: Creates MailCopy from Message metadata
@@ -107,6 +108,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         "ParentFolderId",
         "InternetMessageId",
         "InternetMessageHeaders",
+        "Categories",
     ];
 
     private readonly SemaphoreSlim _handleItemRetrievalSemaphore = new(1);
@@ -116,6 +118,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
     private readonly IOutlookChangeProcessor _outlookChangeProcessor;
     private readonly GraphServiceClient _graphClient;
     private readonly IOutlookSynchronizerErrorHandlerFactory _errorHandlingFactory;
+    private readonly IMailCategoryService _mailCategoryService;
     private bool _isFolderStructureChanged;
 
     private readonly SemaphoreSlim _concurrentDownloadSemaphore = new(10); // Limit to 10 concurrent downloads
@@ -123,7 +126,8 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
     public OutlookSynchronizer(MailAccount account,
                                IAuthenticator authenticator,
                                IOutlookChangeProcessor outlookChangeProcessor,
-                               IOutlookSynchronizerErrorHandlerFactory errorHandlingFactory) : base(account, WeakReferenceMessenger.Default)
+                               IOutlookSynchronizerErrorHandlerFactory errorHandlingFactory,
+                               IMailCategoryService mailCategoryService) : base(account, WeakReferenceMessenger.Default)
     {
         var tokenProvider = new MicrosoftTokenProvider(Account, authenticator);
 
@@ -138,6 +142,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
 
         _outlookChangeProcessor = outlookChangeProcessor;
         _errorHandlingFactory = errorHandlingFactory;
+        _mailCategoryService = mailCategoryService;
     }
 
     #region MS Graph Handlers
@@ -343,9 +348,9 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         // Check if we have a delta token
         if (string.IsNullOrEmpty(folder.DeltaToken))
         {
-            _logger.Debug("No delta token for folder {FolderName}. Starting initial sync (last 30 days).", folder.FolderName);
+            _logger.Debug("No delta token for folder {FolderName}. Starting initial sync.", folder.FolderName);
 
-            // Download mails for initial sync (last 30 days)
+            // Download mails for initial sync using the account's configured cutoff date.
             await DownloadMailsForInitialSyncAsync(folder, downloadedMessageIds, cancellationToken).ConfigureAwait(false);
         }
         else
@@ -367,27 +372,37 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
     }
 
     /// <summary>
-    /// Downloads mails for initial synchronization using Delta API with 30-day filter.
-    /// Downloads metadata only (no MIME content) for messages received in the last 30 days.
+    /// Downloads mails for initial synchronization using Delta API with the account's configured cutoff date.
+    /// Downloads metadata only (no MIME content) for messages received after that date.
     /// </summary>
     private async Task DownloadMailsForInitialSyncAsync(MailItemFolder folder, List<string> downloadedMessageIds, CancellationToken cancellationToken)
     {
-        _logger.Debug("Starting initial mail download for folder {FolderName} (last 6 months)", folder.FolderName);
+        _logger.Debug("Starting initial mail download for folder {FolderName}", folder.FolderName);
 
         try
         {
-            // Calculate date 6 months ago
-            var sixMonthsAgo = DateTime.UtcNow.AddMonths(-6);
-            var filterDate = sixMonthsAgo.ToString("yyyy-MM-ddTHH:mm:ssZ");
+            var referenceDateUtc = Account.CreatedAt ?? DateTime.UtcNow;
+            var initialSynchronizationCutoffDateUtc = Account.InitialSynchronizationRange.ToCutoffDateUtc(referenceDateUtc);
+            var filterDate = initialSynchronizationCutoffDateUtc?.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ");
 
-            _logger.Information("Downloading messages received after {FilterDate} for folder {FolderName}", filterDate, folder.FolderName);
+            if (filterDate != null)
+            {
+                _logger.Information("Downloading messages received after {FilterDate} for folder {FolderName}", filterDate, folder.FolderName);
+            }
+            else
+            {
+                _logger.Information("Downloading all available messages for folder {FolderName}", folder.FolderName);
+            }
 
-            // Use Delta API with receivedDateTime filter for last 6 months
             var messageCollectionPage = await _graphClient.Me.MailFolders[folder.RemoteFolderId].Messages.Delta.GetAsDeltaGetResponseAsync((config) =>
             {
                 config.QueryParameters.Select = outlookMessageSelectParameters;
                 config.QueryParameters.Orderby = ["receivedDateTime desc"];
-                config.QueryParameters.Filter = $"receivedDateTime ge {filterDate}";
+
+                if (filterDate != null)
+                {
+                    config.QueryParameters.Filter = $"receivedDateTime ge {filterDate}";
+                }
             }, cancellationToken).ConfigureAwait(false);
 
             var totalProcessed = 0;
@@ -1142,6 +1157,11 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
                     _logger.Debug("Updating flag status for mail {MessageId}: IsFlagged={IsFlagged}", item.Id, isFlagged);
                     await _outlookChangeProcessor.ChangeFlagStatusAsync(item.Id, isFlagged).ConfigureAwait(false);
                 }
+
+                if (item.Categories != null)
+                {
+                    await ReplaceMailAssignmentsAsync(item.Id, item.Categories).ConfigureAwait(false);
+                }
             }
             else
             {
@@ -1198,6 +1218,43 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         }
     }
 
+    protected override async Task SynchronizeCategoriesAsync(CancellationToken cancellationToken = default)
+    {
+        var response = await _graphClient.Me.Outlook.MasterCategories
+            .GetAsync(cancellationToken: cancellationToken)
+            .ConfigureAwait(false);
+
+        var categories = response?.Value?
+            .Where(a => !string.IsNullOrWhiteSpace(a?.DisplayName))
+            .Select(a =>
+            {
+                var colorOption = GetMailCategoryColorOption(a.Color);
+
+                return new MailCategory
+                {
+                    MailAccountId = Account.Id,
+                    RemoteId = a.Id,
+                    Name = a.DisplayName,
+                    BackgroundColorHex = colorOption.BackgroundColorHex,
+                    TextColorHex = colorOption.TextColorHex,
+                    Source = MailCategorySource.Outlook
+                };
+            })
+            .ToList() ?? [];
+
+        await _mailCategoryService.ReplaceCategoriesAsync(Account.Id, categories).ConfigureAwait(false);
+    }
+
+    private async Task ReplaceMailAssignmentsAsync(string messageId, IEnumerable<string> categoryNames)
+    {
+        var localMailCopies = await _outlookChangeProcessor.GetMailCopiesAsync([messageId]).ConfigureAwait(false);
+
+        foreach (var localMailCopy in localMailCopies)
+        {
+            await _mailCategoryService.ReplaceMailAssignmentsAsync(Account.Id, localMailCopy.UniqueId, categoryNames ?? []).ConfigureAwait(false);
+        }
+    }
+
     private async Task<OutlookSpecialFolderIdInformation> GetSpecialFolderIdsAsync(CancellationToken cancellationToken)
     {
         var localFolders = await _outlookChangeProcessor.GetLocalFoldersAsync(Account.Id).ConfigureAwait(false);
@@ -1757,6 +1814,87 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         return Move(batchMoveRequest);
     }
 
+    public override List<IRequestBundle<RequestInformation>> UpdateCategories(BatchMailCategoryAssignmentRequest request)
+        => ForEachRequest(request, item => CreateMessageCategoryPatchRequest(item.Item.Id, item.CategoryNames));
+
+    public override List<IRequestBundle<RequestInformation>> CreateCategory(MailCategoryCreateRequest request)
+    {
+        var outlookCategory = new OutlookCategory
+        {
+            DisplayName = request.Category.Name,
+            Color = GetOutlookCategoryColor(request.Category)
+        };
+
+        var requestInfo = _graphClient.Me.Outlook.MasterCategories.ToPostRequestInformation(outlookCategory);
+        return [new HttpRequestBundle<RequestInformation>(requestInfo, request)];
+    }
+
+    public override List<IRequestBundle<RequestInformation>> UpdateCategory(MailCategoryUpdateRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.PreviousRemoteId))
+            return CreateCategory(new MailCategoryCreateRequest(request.Category));
+
+        var hasNameChanged = !string.Equals(request.PreviousName, request.Category.Name, StringComparison.Ordinal);
+        if (!hasNameChanged)
+        {
+            var requestInfo = _graphClient.Me.Outlook.MasterCategories[request.PreviousRemoteId].ToPatchRequestInformation(new OutlookCategory
+            {
+                Color = GetOutlookCategoryColor(request.Category)
+            });
+
+            return [new HttpRequestBundle<RequestInformation>(requestInfo, request)];
+        }
+
+        var bundles = new List<IRequestBundle<RequestInformation>>();
+        var createRequestInfo = _graphClient.Me.Outlook.MasterCategories.ToPostRequestInformation(new OutlookCategory
+        {
+            DisplayName = request.Category.Name,
+            Color = GetOutlookCategoryColor(request.Category)
+        });
+
+        bundles.Add(new HttpRequestBundle<RequestInformation>(createRequestInfo, request));
+
+        foreach (var target in request.AffectedMessages ?? [])
+        {
+            bundles.Add(new HttpRequestBundle<RequestInformation>(
+                CreateMessageCategoryPatchRequest(target.MessageId, target.CategoryNames),
+                request));
+        }
+
+        bundles.Add(new HttpRequestBundle<RequestInformation>(
+            _graphClient.Me.Outlook.MasterCategories[request.PreviousRemoteId].ToDeleteRequestInformation(),
+            request));
+
+        return bundles;
+    }
+
+    public override List<IRequestBundle<RequestInformation>> DeleteCategory(MailCategoryDeleteRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.PreviousRemoteId))
+            return [];
+
+        var bundles = new List<IRequestBundle<RequestInformation>>();
+
+        foreach (var target in request.AffectedMessages ?? [])
+        {
+            bundles.Add(new HttpRequestBundle<RequestInformation>(
+                CreateMessageCategoryPatchRequest(target.MessageId, target.CategoryNames),
+                request));
+        }
+
+        bundles.Add(new HttpRequestBundle<RequestInformation>(
+            _graphClient.Me.Outlook.MasterCategories[request.PreviousRemoteId].ToDeleteRequestInformation(),
+            request));
+
+        return bundles;
+    }
+
+    private RequestInformation CreateMessageCategoryPatchRequest(string messageId, IReadOnlyList<string> categoryNames)
+        => _graphClient.Me.Messages[messageId].ToPatchRequestInformation(new Message
+        {
+            Categories = categoryNames?.ToList() ?? []
+        });
+
     public override async Task DownloadMissingMimeMessageAsync(MailCopy mailItem,
                                                            MailKit.ITransferProgress transferProgress = null,
                                                            CancellationToken cancellationToken = default)
@@ -1952,7 +2090,9 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         for (int i = 0; i < itemCount; i++)
         {
             var bundle = batch.ElementAt(i);
-            requiresSerial |= bundle.UIChangeRequest is SendDraftRequest;
+            requiresSerial |= bundle.UIChangeRequest is SendDraftRequest
+                              or MailCategoryUpdateRequest
+                              or MailCategoryDeleteRequest;
 
             // UI changes are already applied in ExecuteNativeRequestsAsync before batching.
             var batchRequestId = await batchContent.AddBatchRequestStepAsync(bundle.NativeRequest);
@@ -2100,7 +2240,10 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
            || request is ChangeFlagRequest
            || request is MarkReadRequest
            || request is ArchiveRequest
+           || request is MailCategoryAssignmentRequest
            || request is RenameFolderRequest
+           || request is MailCategoryUpdateRequest
+           || request is MailCategoryDeleteRequest
            || request is DeleteFolderRequest
            || request is AcceptEventRequest
            || request is DeclineEventRequest
@@ -2155,6 +2298,26 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
                     return;
 
                 await UploadCalendarEventAttachmentsAsync(createCalendarEventRequest, createdEventId, CancellationToken.None).ConfigureAwait(false);
+                return;
+            }
+
+            if (bundle?.UIChangeRequest is MailCategoryCreateRequest createCategoryRequest)
+            {
+                var createdCategoryId = json?["id"]?.GetValue<string>();
+                if (!string.IsNullOrWhiteSpace(createdCategoryId))
+                {
+                    await _mailCategoryService.UpdateRemoteIdAsync(createCategoryRequest.Category.Id, createdCategoryId).ConfigureAwait(false);
+                }
+                return;
+            }
+
+            if (bundle?.UIChangeRequest is MailCategoryUpdateRequest updateCategoryRequest)
+            {
+                var updatedCategoryId = json?["id"]?.GetValue<string>();
+                if (!string.IsNullOrWhiteSpace(updatedCategoryId))
+                {
+                    await _mailCategoryService.UpdateRemoteIdAsync(updateCategoryRequest.Category.Id, updatedCategoryId).ConfigureAwait(false);
+                }
             }
         }
         catch (Exception ex)
@@ -2357,11 +2520,68 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         // Outlook messages can only be assigned to 1 folder at a time.
         // Therefore we don't need to create multiple copies of the same message for different folders.
         var contacts = ExtractContactsFromOutlookMessage(message);
-        var package = new NewMailItemPackage(mailCopy, mimeMessage, assignedFolder.RemoteFolderId, contacts);
+        var package = new NewMailItemPackage(mailCopy, mimeMessage, assignedFolder.RemoteFolderId, contacts, message.Categories);
 
         return [package];
     }
 
+    private static MailCategoryColorOption GetMailCategoryColorOption(CategoryColor? color)
+        => color switch
+        {
+            CategoryColor.Preset0 => new("#FEE2E2", "#991B1B"),
+            CategoryColor.Preset1 => new("#FFEDD5", "#9A3412"),
+            CategoryColor.Preset2 => new("#FEF3C7", "#92400E"),
+            CategoryColor.Preset3 => new("#ECFCCB", "#3F6212"),
+            CategoryColor.Preset4 => new("#DCFCE7", "#166534"),
+            CategoryColor.Preset5 => new("#CCFBF1", "#115E59"),
+            CategoryColor.Preset6 => new("#CFFAFE", "#155E75"),
+            CategoryColor.Preset7 => new("#DBEAFE", "#1D4ED8"),
+            CategoryColor.Preset8 => new("#E0E7FF", "#4338CA"),
+            CategoryColor.Preset9 => new("#F3E8FF", "#7E22CE"),
+            CategoryColor.Preset10 => new("#FCE7F3", "#9D174D"),
+            CategoryColor.Preset11 => new("#FECACA", "#7F1D1D"),
+            CategoryColor.Preset12 => new("#FED7AA", "#7C2D12"),
+            CategoryColor.Preset13 => new("#FDE68A", "#78350F"),
+            CategoryColor.Preset14 => new("#D9F99D", "#365314"),
+            CategoryColor.Preset15 => new("#BBF7D0", "#14532D"),
+            CategoryColor.Preset16 => new("#99F6E4", "#134E4A"),
+            CategoryColor.Preset17 => new("#A5F3FC", "#164E63"),
+            CategoryColor.Preset18 => new("#BFDBFE", "#1E3A8A"),
+            CategoryColor.Preset19 => new("#DDD6FE", "#5B21B6"),
+            CategoryColor.Preset20 => new("#E5E7EB", "#374151"),
+            CategoryColor.Preset21 => new("#D1D5DB", "#1F2937"),
+            CategoryColor.Preset22 => new("#F3F4F6", "#111827"),
+            CategoryColor.Preset23 => new("#E2E8F0", "#334155"),
+            CategoryColor.Preset24 => new("#F8FAFC", "#475569"),
+            _ => new("#E5E7EB", "#374151")
+        };
+
+    private static CategoryColor GetOutlookCategoryColor(MailCategory category)
+        => (category.BackgroundColorHex?.ToUpperInvariant(), category.TextColorHex?.ToUpperInvariant()) switch
+        {
+            ("#FEE2E2", "#991B1B") => CategoryColor.Preset0,
+            ("#FFEDD5", "#9A3412") => CategoryColor.Preset1,
+            ("#FEF3C7", "#92400E") => CategoryColor.Preset2,
+            ("#ECFCCB", "#3F6212") => CategoryColor.Preset3,
+            ("#DCFCE7", "#166534") => CategoryColor.Preset4,
+            ("#CCFBF1", "#115E59") => CategoryColor.Preset5,
+            ("#CFFAFE", "#155E75") => CategoryColor.Preset6,
+            ("#DBEAFE", "#1D4ED8") => CategoryColor.Preset7,
+            ("#E0E7FF", "#4338CA") => CategoryColor.Preset8,
+            ("#F3E8FF", "#7E22CE") => CategoryColor.Preset9,
+            ("#FCE7F3", "#9D174D") => CategoryColor.Preset10,
+            ("#FECACA", "#7F1D1D") => CategoryColor.Preset11,
+            ("#FED7AA", "#7C2D12") => CategoryColor.Preset12,
+            ("#FDE68A", "#78350F") => CategoryColor.Preset13,
+            ("#D9F99D", "#365314") => CategoryColor.Preset14,
+            ("#BBF7D0", "#14532D") => CategoryColor.Preset15,
+            ("#99F6E4", "#134E4A") => CategoryColor.Preset16,
+            ("#A5F3FC", "#164E63") => CategoryColor.Preset17,
+            ("#BFDBFE", "#1E3A8A") => CategoryColor.Preset18,
+            ("#DDD6FE", "#5B21B6") => CategoryColor.Preset19,
+            _ => CategoryColor.Preset0
+        };
+
     private async Task TryMapCalendarInvitationAsync(MailCopy mailCopy, MimeMessage mimeMessage, CancellationToken cancellationToken)
     {
         if (mailCopy.ItemType != MailItemType.CalendarInvitation || mimeMessage == null)
@@ -2664,6 +2884,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
                 {
                     existingLocalCalendar.Name = calendar.Name;
                     existingLocalCalendar.IsPrimary = string.Equals(existingLocalCalendar.RemoteCalendarId, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+                    existingLocalCalendar.IsReadOnly = !calendar.CanEdit.GetValueOrDefault(true);
                     existingLocalCalendar.BackgroundColorHex = resolvedColor;
                     existingLocalCalendar.TextColorHex = ColorHelpers.GetReadableTextColorHex(existingLocalCalendar.BackgroundColorHex);
 
@@ -2702,12 +2923,14 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         var remoteCalendarName = calendar.Name;
         var remoteBackgroundColor = ResolveSynchronizedCalendarBackgroundColor(GetRemoteOutlookCalendarBackgroundColor(calendar), accountCalendar);
         var remoteIsPrimary = string.Equals(calendar.Id, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+        var remoteIsReadOnly = !calendar.CanEdit.GetValueOrDefault(true);
 
         bool isNameChanged = !string.Equals(accountCalendar.Name, remoteCalendarName, StringComparison.OrdinalIgnoreCase);
         bool isBackgroundColorChanged = !string.Equals(accountCalendar.BackgroundColorHex, remoteBackgroundColor, StringComparison.OrdinalIgnoreCase);
         bool isPrimaryChanged = accountCalendar.IsPrimary != remoteIsPrimary;
+        bool isReadOnlyChanged = accountCalendar.IsReadOnly != remoteIsReadOnly;
 
-        return isNameChanged || isBackgroundColorChanged || isPrimaryChanged;
+        return isNameChanged || isBackgroundColorChanged || isPrimaryChanged || isReadOnlyChanged;
     }
 
     private static string GetRemoteOutlookCalendarBackgroundColor(Calendar calendar)

Wino.Core/Synchronizers/WinoSynchronizer.cs

@@ -20,6 +20,7 @@ using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.Domain.Models.Synchronization;
 using Wino.Core.Requests.Bundles;
 using Wino.Core.Requests.Calendar;
+using Wino.Core.Requests.Category;
 using Wino.Core.Requests.Folder;
 using Wino.Core.Requests.Mail;
 using Wino.Messaging.UI;
@@ -63,6 +64,7 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
     /// Only available for Gmail right now.
     /// </summary>
     protected virtual Task SynchronizeAliasesAsync() => Task.CompletedTask;
+    protected virtual Task SynchronizeCategoriesAsync(CancellationToken cancellationToken = default) => Task.CompletedTask;
 
     /// <summary>
     /// Queues all mail ids for initial synchronization for a specific folder.
@@ -194,6 +196,9 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
                             case MailSynchronizerOperation.Archive:
                                 nativeRequests.AddRange(Archive(new BatchArchiveRequest(group.Cast<ArchiveRequest>())));
                                 break;
+                            case MailSynchronizerOperation.UpdateCategories:
+                                nativeRequests.AddRange(UpdateCategories(new BatchMailCategoryAssignmentRequest(group.Cast<MailCategoryAssignmentRequest>())));
+                                break;
                             default:
                                 break;
                         }
@@ -221,6 +226,23 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
                                 break;
                         }
                     }
+                    else if (key is CategorySynchronizerOperation categorySynchronizerOperation)
+                    {
+                        switch (categorySynchronizerOperation)
+                        {
+                            case CategorySynchronizerOperation.CreateCategory:
+                                nativeRequests.AddRange(CreateCategory(group.ElementAt(0) as MailCategoryCreateRequest));
+                                break;
+                            case CategorySynchronizerOperation.UpdateCategory:
+                                nativeRequests.AddRange(UpdateCategory(group.ElementAt(0) as MailCategoryUpdateRequest));
+                                break;
+                            case CategorySynchronizerOperation.DeleteCategory:
+                                nativeRequests.AddRange(DeleteCategory(group.ElementAt(0) as MailCategoryDeleteRequest));
+                                break;
+                            default:
+                                break;
+                        }
+                    }
                 }
 
                 changeRequestQueue.Clear();
@@ -322,6 +344,30 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
                 }
             }
 
+            // Category definition sync.
+            if (options.Type == MailSynchronizationType.Categories)
+            {
+                if (!Account.IsCategorySyncSupported) return MailSynchronizationResult.Empty;
+
+                try
+                {
+                    await SynchronizeCategoriesAsync(activeSynchronizationCancellationToken);
+
+                    return FinalizeMailResult(MailSynchronizationResult.Empty);
+                }
+                catch (AuthenticationAttentionException)
+                {
+                    throw;
+                }
+                catch (Exception ex)
+                {
+                    Log.Error(ex, "Failed to update categories for {Name}", Account.Name);
+
+                    CaptureSynchronizationIssue(SynchronizationIssue.FromException(ex, "CategorySync"));
+                    return FinalizeMailResult(MailSynchronizationResult.Failed(ex));
+                }
+            }
+
             if (shouldDelayExecution)
             {
                 await Task.Delay(maxExecutionDelay);
@@ -526,6 +572,16 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
     /// <returns>New synchronization options with minimal HTTP effort.</returns>
     private MailSynchronizationOptions GetSynchronizationOptionsAfterRequestExecution(List<IRequestBase> requests, Guid existingSynchronizationId)
     {
+        if (requests.All(a => a is ICategoryActionRequest or MailCategoryAssignmentRequest))
+        {
+            return new MailSynchronizationOptions
+            {
+                AccountId = Account.Id,
+                Id = existingSynchronizationId,
+                Type = MailSynchronizationType.FoldersOnly
+            };
+        }
+
         List<Guid> synchronizationFolderIds = requests
                 .Where(a => a is ICustomFolderSynchronizationRequest)
                 .Cast<ICustomFolderSynchronizationRequest>()
@@ -602,6 +658,10 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
     public virtual List<IRequestBundle<TBaseRequest>> MarkFolderAsRead(MarkFolderAsReadRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
     public virtual List<IRequestBundle<TBaseRequest>> DeleteFolder(DeleteFolderRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
     public virtual List<IRequestBundle<TBaseRequest>> CreateSubFolder(CreateSubFolderRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> UpdateCategories(BatchMailCategoryAssignmentRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> CreateCategory(MailCategoryCreateRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> UpdateCategory(MailCategoryUpdateRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> DeleteCategory(MailCategoryDeleteRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
 
     #endregion
 

Wino.Mail.ViewModels/AccountDetailsPageViewModel.cs

@@ -2,24 +2,25 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
+using System.Globalization;
 using System.Linq;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using CommunityToolkit.Mvvm.Messaging;
-using Wino.Core.Misc;
-using Wino.Core.Domain.Entities.Calendar;
 using Wino.Core.Domain;
+using Wino.Core.Domain.Entities.Calendar;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Extensions;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.Folders;
 using Wino.Core.Domain.Models.Navigation;
+using Wino.Core.Misc;
 using Wino.Core.Services;
 using Wino.Core.ViewModels.Data;
 using Wino.Mail.ViewModels.Data;
-using Wino.Messaging.Client.Calendar;
 using Wino.Messaging.Client.Navigation;
 
 namespace Wino.Mail.ViewModels;
@@ -101,6 +102,14 @@ public partial class AccountDetailsPageViewModel : MailBaseViewModel
         ? $"ms-appx:///Assets/Providers/{Account.SpecialImapProvider}.png"
         : $"ms-appx:///Assets/Providers/{Account?.ProviderType}.png";
     public string Address => Account?.Address ?? string.Empty;
+    public bool IsInitialSynchronizationSummaryVisible => Account?.CreatedAt.HasValue == true && Account.InitialSynchronizationRange != InitialSynchronizationRange.Everything;
+    public string InitialSynchronizationSummary => Account?.CreatedAt is not DateTime createdAtUtc
+        ? string.Empty
+        : Account.InitialSynchronizationRange.ToCutoffDateUtc(createdAtUtc) is not DateTime cutoffDateUtc
+            ? string.Empty
+            : string.Format(
+            Translator.AccountDetailsPage_InitialSynchronization_Description,
+            cutoffDateUtc.ToLocalTime().ToString("D", CultureInfo.CurrentUICulture));
 
     public List<ImapAuthenticationMethodModel> AvailableAuthenticationMethods { get; } =
     [
@@ -160,6 +169,10 @@ public partial class AccountDetailsPageViewModel : MailBaseViewModel
     private void EditAliases()
         => Messenger.Send(new BreadcrumbNavigationRequested(Translator.SettingsManageAliases_Title, WinoPage.AliasManagementPage, Account.Id));
 
+    [RelayCommand]
+    private void EditCategories()
+        => Messenger.Send(new BreadcrumbNavigationRequested(Translator.MailCategoryManagementPage_Title, WinoPage.MailCategoryManagementPage, Account.Id));
+
     [RelayCommand]
     private void EditImapCalDavSettings()
         => Messenger.Send(new BreadcrumbNavigationRequested(
@@ -363,13 +376,15 @@ public partial class AccountDetailsPageViewModel : MailBaseViewModel
         OnPropertyChanged(nameof(IsFocusedInboxSupportedForAccount));
         OnPropertyChanged(nameof(ProviderIconPath));
         OnPropertyChanged(nameof(Address));
+        OnPropertyChanged(nameof(IsInitialSynchronizationSummaryVisible));
+        OnPropertyChanged(nameof(InitialSynchronizationSummary));
     }
 
     protected override async void OnPropertyChanged(PropertyChangedEventArgs e)
     {
         base.OnPropertyChanged(e);
 
-        if (!IsActive || !isLoaded) return;
+        if (!isLoaded) return;
 
         switch (e.PropertyName)
         {

Wino.Mail.ViewModels/AccountSetupProgressPageViewModel.cs

@@ -81,6 +81,10 @@ public partial class AccountSetupProgressPageViewModel : MailBaseViewModel
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_FetchingProfile });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SavingAccount });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SyncingFolders });
+            if (WizardContext.SelectedProvider.Type == MailProviderType.Outlook)
+            {
+                Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SyncingCategories });
+            }
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_FetchingCalendarMetadata });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SyncingAliases });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_Finalizing });
@@ -170,6 +174,7 @@ public partial class AccountSetupProgressPageViewModel : MailBaseViewModel
         try
         {
             CustomServerInformation customServerInformation = null;
+            var accountCreatedAt = DateTime.UtcNow;
 
             // Build account in memory
             _createdAccount = new MailAccount
@@ -179,6 +184,8 @@ public partial class AccountSetupProgressPageViewModel : MailBaseViewModel
                 Name = WizardContext.AccountName,
                 SpecialImapProvider = WizardContext.SelectedProvider.SpecialImapProvider,
                 AccountColorHex = WizardContext.AccountColorHex,
+                CreatedAt = accountCreatedAt,
+                InitialSynchronizationRange = WizardContext.SelectedInitialSynchronizationRange,
                 IsCalendarAccessGranted = true
             };
 
@@ -226,6 +233,16 @@ public partial class AccountSetupProgressPageViewModel : MailBaseViewModel
                     throw new Exception(Translator.Exception_FailedToSynchronizeFolders);
                 SetCurrentStepSucceeded();
 
+                // Step: Categories
+                if (_createdAccount.IsCategorySyncSupported)
+                {
+                    SetStepInProgress(Translator.AccountSetup_Step_SyncingCategories);
+                    var categoryResult = await SynchronizationManager.Instance.SynchronizeCategoriesAsync(_createdAccount.Id);
+                    if (categoryResult.CompletedState != SynchronizationCompletedState.Success)
+                        throw new Exception(Translator.Exception_FailedToSynchronizeCategories);
+                    SetCurrentStepSucceeded();
+                }
+
                 // Step: Calendar metadata
                 SetStepInProgress(Translator.AccountSetup_Step_FetchingCalendarMetadata);
                 if (_createdAccount.IsCalendarAccessGranted)

Wino.Mail.ViewModels/ComposePageViewModel.cs

@@ -19,6 +19,7 @@ using Wino.Core.Domain.Extensions;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.Domain.Models;
+using Wino.Core.Domain.Models.Launch;
 using Wino.Core.Domain.Models.Navigation;
 using Wino.Core.Extensions;
 using Wino.Core.Services;
@@ -159,6 +160,7 @@ public partial class ComposePageViewModel : MailBaseViewModel,
     public readonly IPreferencesService PreferencesService;
     public readonly IContactService ContactService;
     public readonly ISmimeCertificateService _smimeCertificateService;
+    private readonly IShareActivationService _shareActivationService;
 
     public ComposePageViewModel(IMailDialogService dialogService,
                                 IMailService mailService,
@@ -172,7 +174,8 @@ public partial class ComposePageViewModel : MailBaseViewModel,
                                 IContactService contactService,
                                 IFontService fontService,
                                 IPreferencesService preferencesService,
-                                ISmimeCertificateService smimeCertificateService)
+                                ISmimeCertificateService smimeCertificateService,
+                                IShareActivationService shareActivationService)
     {
         NativeAppService = nativeAppService;
         ContactService = contactService;
@@ -188,6 +191,7 @@ public partial class ComposePageViewModel : MailBaseViewModel,
         _emailTemplateService = emailTemplateService;
         _worker = worker;
         _smimeCertificateService = smimeCertificateService;
+        _shareActivationService = shareActivationService;
 
         foreach (var cert in _smimeCertificateService.GetCertificates(emailAddress: SelectedAlias?.AliasAddress))
         {
@@ -752,6 +756,7 @@ public partial class ComposePageViewModel : MailBaseViewModel,
             await LoadAddressInfoAsync(replyingMime.Bcc, BCCItems);
 
             LoadAttachments();
+            ApplyPendingSharedAttachments();
 
             if (replyingMime.Cc.Any() || replyingMime.Bcc.Any())
                 IsCCBCCVisible = true;
@@ -783,6 +788,24 @@ public partial class ComposePageViewModel : MailBaseViewModel,
         }
     }
 
+    private void ApplyPendingSharedAttachments()
+    {
+        var draftUniqueId = CurrentMailDraftItem?.MailCopy?.UniqueId ?? Guid.Empty;
+
+        if (draftUniqueId == Guid.Empty)
+            return;
+
+        var shareRequest = _shareActivationService.ConsumePendingComposeShareRequest(draftUniqueId);
+
+        if (shareRequest?.Files == null || shareRequest.Files.Count == 0)
+            return;
+
+        foreach (var sharedFile in shareRequest.Files)
+        {
+            IncludedAttachments.Add(new MailAttachmentViewModel(sharedFile));
+        }
+    }
+
     private async Task LoadAddressInfoAsync(InternetAddressList list, ObservableCollection<AccountContact> collection)
     {
         foreach (var item in list)

Wino.Mail.ViewModels/Data/WelcomeWizardContext.cs

@@ -18,6 +18,9 @@ public partial class WelcomeWizardContext : ObservableObject
     [ObservableProperty]
     public partial string AccountColorHex { get; set; }
 
+    [ObservableProperty]
+    public partial InitialSynchronizationRange SelectedInitialSynchronizationRange { get; set; } = InitialSynchronizationRange.SixMonths;
+
     // Special IMAP fields (iCloud/Yahoo)
     [ObservableProperty]
     public partial string DisplayName { get; set; }
@@ -62,7 +65,8 @@ public partial class WelcomeWizardContext : ObservableObject
             SelectedProvider.Type,
             AccountName,
             BuildSpecialImapProviderDetails(),
-            AccountColorHex);
+            AccountColorHex,
+            SelectedInitialSynchronizationRange);
     }
 
     public void Reset()
@@ -70,6 +74,7 @@ public partial class WelcomeWizardContext : ObservableObject
         SelectedProvider = null;
         AccountName = null;
         AccountColorHex = null;
+        SelectedInitialSynchronizationRange = InitialSynchronizationRange.SixMonths;
         DisplayName = null;
         EmailAddress = null;
         AppSpecificPassword = null;

Wino.Mail.ViewModels/ImapCalDavSettingsPageViewModel.cs

@@ -16,7 +16,6 @@ using Wino.Core.Domain.Models.Navigation;
 using Wino.Core.Domain.Models.Synchronization;
 using Wino.Core.Services;
 using Wino.Mail.ViewModels.Data;
-using Wino.Messaging.Client.Calendar;
 using Wino.Messaging.Client.Navigation;
 using Wino.Messaging.Server;
 
@@ -319,7 +318,7 @@ public partial class ImapCalDavSettingsPageViewModel : MailBaseViewModel
         try
         {
             var minimalSettings = BuildMinimalSettingsOrThrow();
-            await AutoDiscoverAndApplySettingsAsync(minimalSettings).ConfigureAwait(false);
+            await AutoDiscoverAndApplySettingsAsync(minimalSettings);
 
             _mailDialogService.InfoBarMessage(
                 Translator.IMAPSetupDialog_ValidationSuccess_Title,
@@ -399,7 +398,7 @@ public partial class ImapCalDavSettingsPageViewModel : MailBaseViewModel
     {
         try
         {
-            await EnsureImapSettingsPreparedAsync().ConfigureAwait(false);
+            await EnsureImapSettingsPreparedAsync();
 
             var serverInformation = BuildServerInformation();
 
@@ -407,12 +406,12 @@ public partial class ImapCalDavSettingsPageViewModel : MailBaseViewModel
             ValidateImapSettings(serverInformation);
             ValidateCalendarModeSpecificSettings(serverInformation);
 
-            await ValidateImapConnectivityAsync(serverInformation).ConfigureAwait(false);
+            await ValidateImapConnectivityAsync(serverInformation);
             IsImapValidationSucceeded = true;
 
             if (serverInformation.CalendarSupportMode == ImapCalendarSupportMode.CalDav)
             {
-                await ValidateCalDavConnectivityAsync(serverInformation).ConfigureAwait(false);
+                await ValidateCalDavConnectivityAsync(serverInformation);
                 IsCalDavValidationSucceeded = true;
             }
             else
@@ -432,7 +431,7 @@ public partial class ImapCalDavSettingsPageViewModel : MailBaseViewModel
                 return;
             }
 
-            await SaveEditFlowAsync(serverInformation).ConfigureAwait(false);
+            await SaveEditFlowAsync(serverInformation);
         }
         catch (Exception ex)
         {
@@ -654,7 +653,7 @@ public partial class ImapCalDavSettingsPageViewModel : MailBaseViewModel
             return;
 
         var minimalSettings = BuildMinimalSettingsOrThrow();
-        await AutoDiscoverAndApplySettingsAsync(minimalSettings).ConfigureAwait(false);
+        await AutoDiscoverAndApplySettingsAsync(minimalSettings);
 
         if (!HasCompleteImapSettings())
             throw new InvalidOperationException(Translator.Exception_ImapAutoDiscoveryFailed);
@@ -676,22 +675,25 @@ public partial class ImapCalDavSettingsPageViewModel : MailBaseViewModel
         if (serverInformation == null)
             throw new InvalidOperationException(Translator.Exception_ImapAutoDiscoveryFailed);
 
-        ApplyServerInformation(serverInformation);
-
-        if (IsCalendarSupportEnabled && SelectedCalendarSupportMode == ImapCalendarSupportMode.CalDav)
+        await ExecuteUIThread(async () =>
         {
-            var discoveredCalDavUri = await _autoDiscoveryService.DiscoverCalDavServiceUriAsync(minimalSettings.Email).ConfigureAwait(false);
-            if (discoveredCalDavUri != null)
+            ApplyServerInformation(serverInformation);
+
+            if (IsCalendarSupportEnabled && SelectedCalendarSupportMode == ImapCalendarSupportMode.CalDav)
             {
-                CalDavServiceUrl = discoveredCalDavUri.ToString();
+                var discoveredCalDavUri = await _autoDiscoveryService.DiscoverCalDavServiceUriAsync(minimalSettings.Email);
+                if (discoveredCalDavUri != null)
+                {
+                    CalDavServiceUrl = discoveredCalDavUri.ToString();
+                }
+
+                if (string.IsNullOrWhiteSpace(CalDavUsername))
+                    CalDavUsername = minimalSettings.Email;
+
+                if (string.IsNullOrWhiteSpace(CalDavPassword))
+                    CalDavPassword = minimalSettings.Password;
             }
-
-            if (string.IsNullOrWhiteSpace(CalDavUsername))
-                CalDavUsername = minimalSettings.Email;
-
-            if (string.IsNullOrWhiteSpace(CalDavPassword))
-                CalDavPassword = minimalSettings.Password;
-        }
+        });
     }
     private async Task ValidateImapConnectivityAsync(CustomServerInformation serverInformation)
     {
@@ -995,7 +997,12 @@ public partial class ImapCalDavSettingsPageViewModel : MailBaseViewModel
                 SpecialImapProvider = _editingSpecialImapProvider,
                 IsCalendarAccessGranted = mode != ImapCalendarSupportMode.Disabled
             },
-            new AccountCreationDialogResult(MailProviderType.IMAP4, DisplayName.Trim(), providerDetails, string.Empty));
+            new AccountCreationDialogResult(
+                MailProviderType.IMAP4,
+                DisplayName.Trim(),
+                providerDetails,
+                string.Empty,
+                _wizardContext.SelectedInitialSynchronizationRange));
 
         if (serverInformation == null)
             return false;

Wino.Mail.ViewModels/MailAppShellViewModel.cs

@@ -15,8 +15,9 @@ using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.MenuItems;
-using Wino.Core.Domain.Models.Folders;
 using Wino.Core.Domain.Models;
+using Wino.Core.Domain.Models.Folders;
+using Wino.Core.Domain.Models.Launch;
 using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.Domain.Models.Navigation;
 using Wino.Core.Domain.Models.Synchronization;
@@ -72,6 +73,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
     public IMenuItem CreatePrimaryMenuItem => CreateMailMenuItem;
 
     private readonly IFolderService _folderService;
+    private readonly IMailCategoryService _mailCategoryService;
     private readonly IConfigurationService _configurationService;
     private readonly IStartupBehaviorService _startupBehaviorService;
     private readonly IAccountService _accountService;
@@ -84,6 +86,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
     private readonly IMimeFileService _mimeFileService;
     private readonly IWebView2RuntimeValidatorService _webView2RuntimeValidatorService;
     private readonly IStoreUpdateService _storeUpdateService;
+    private readonly IShareActivationService _shareActivationService;
 
     private readonly INativeAppService _nativeAppService;
     private readonly IMailService _mailService;
@@ -97,6 +100,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
                              IMimeFileService mimeFileService,
                              INativeAppService nativeAppService,
                              IMailService mailService,
+                             IMailCategoryService mailCategoryService,
                              IAccountService accountService,
                              IContextMenuItemService contextMenuItemService,
                              IStoreRatingService storeRatingService,
@@ -109,7 +113,8 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
                              IConfigurationService configurationService,
                              IStartupBehaviorService startupBehaviorService,
                              IWebView2RuntimeValidatorService webView2RuntimeValidatorService,
-                             IStoreUpdateService storeUpdateService)
+                             IStoreUpdateService storeUpdateService,
+                             IShareActivationService shareActivationService)
     {
         StatePersistenceService = statePersistanceService;
 
@@ -122,6 +127,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         _mimeFileService = mimeFileService;
         _nativeAppService = nativeAppService;
         _mailService = mailService;
+        _mailCategoryService = mailCategoryService;
         _folderService = folderService;
         _accountService = accountService;
         _contextMenuItemService = contextMenuItemService;
@@ -131,6 +137,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         _winoRequestDelegator = winoRequestDelegator;
         _webView2RuntimeValidatorService = webView2RuntimeValidatorService;
         _storeUpdateService = storeUpdateService;
+        _shareActivationService = shareActivationService;
     }
 
     protected override void OnDispatcherAssigned()
@@ -274,6 +281,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         }
 
         await ProcessLaunchOptionsAsync();
+        await HandlePendingShareRequestAsync();
         await ValidateWebView2RuntimeAsync();
 
         if (shouldRunStartupFlows && !Debugger.IsAttached)
@@ -716,7 +724,8 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         {
             await HandleCreateNewMailAsync();
         }
-        else if (clickedMenuItem is IBaseFolderMenuItem baseFolderMenuItem && baseFolderMenuItem.HandlingFolders.All(a => a.IsMoveTarget))
+        else if (clickedMenuItem is IBaseFolderMenuItem baseFolderMenuItem &&
+                 (clickedMenuItem is IMailCategoryMenuItem or IMergedMailCategoryMenuItem || baseFolderMenuItem.HandlingFolders.All(a => a.IsMoveTarget)))
         {
             // Don't navigate to base folders that contain non-move target folders.
             // Theory: This is a special folder like Categories or More. Don't navigate to it.
@@ -788,11 +797,20 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
     {
         // Get visible account menu items, ordered by merged accounts at the last.
         // We will update the unread counts for all single accounts and trigger UI refresh for merged menu items.
-        var accountMenuItems = MenuItems.GetAllAccountMenuItems().OrderBy(a => a.HoldingAccounts.Count());
+        List<IAccountMenuItem> accountMenuItems = null;
+
+        await ExecuteUIThread(() =>
+        {
+            accountMenuItems = MenuItems
+                .GetAllAccountMenuItems()
+                .OrderBy(a => a.HoldingAccounts.Count())
+                .ToList();
+        });
 
         // Individually get all single accounts' unread counts.
-        var accountIds = accountMenuItems.OfType<AccountMenuItem>().Select(a => a.AccountId);
+        var accountIds = accountMenuItems.OfType<AccountMenuItem>().Select(a => a.AccountId).ToList();
         var unreadCountResult = await _folderService.GetUnreadItemCountResultsAsync(accountIds).ConfigureAwait(false);
+        var unreadCategoryCountResult = await _mailCategoryService.GetUnreadCategoryCountResultsAsync(accountIds).ConfigureAwait(false);
 
         // Recursively update all folders' unread counts to 0.
         // Query above only returns unread counts that exists. We need to reset the rest to 0 first.
@@ -844,6 +862,29 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
             }
         }
 
+        foreach (var unreadCategoryCount in unreadCategoryCountResult)
+        {
+            if (MenuItems.TryGetCategoryMenuItem(unreadCategoryCount.CategoryId, out var categoryMenuItem))
+            {
+                if (categoryMenuItem is IMergedMailCategoryMenuItem mergedCategoryMenuItem)
+                {
+                    await ExecuteUIThread(() =>
+                    {
+                        categoryMenuItem.UnreadItemCount = unreadCategoryCountResult
+                            .Where(a => mergedCategoryMenuItem.Categories.Any(b => b.Id == a.CategoryId))
+                            .Sum(a => a.UnreadItemCount);
+                    });
+                }
+                else
+                {
+                    await ExecuteUIThread(() =>
+                    {
+                        categoryMenuItem.UnreadItemCount = unreadCategoryCount.UnreadItemCount;
+                    });
+                }
+            }
+        }
+
         // Update unread badge after all unread counts are updated.
         await _notificationBuilder.UpdateTaskbarIconBadgeAsync();
     }
@@ -943,6 +984,9 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
     }
 
     public async Task CreateNewMailForAsync(MailAccount account)
+        => await CreateNewMailForAsync(account, null);
+
+    public async Task CreateNewMailForAsync(MailAccount account, MailShareRequest shareRequest)
     {
         if (account == null) return;
 
@@ -974,6 +1018,11 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
 
         var (draftMailCopy, draftBase64MimeMessage) = await _mailService.CreateDraftAsync(account.Id, draftOptions).ConfigureAwait(false);
 
+        if (shareRequest?.Files?.Count > 0)
+        {
+            _shareActivationService.StagePendingComposeShareRequest(draftMailCopy.UniqueId, shareRequest);
+        }
+
         var draftPreparationRequest = new DraftPreparationRequest(account, draftMailCopy, draftBase64MimeMessage, draftOptions.Reason);
         await _winoRequestDelegator.ExecuteAsync(draftPreparationRequest);
     }
@@ -1034,6 +1083,35 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         await CreateNewMailForAsync(targetAccount);
     }
 
+    public async Task HandlePendingShareRequestAsync()
+    {
+        var shareRequest = _shareActivationService.ConsumePendingShareRequest();
+
+        if (shareRequest?.Files == null || shareRequest.Files.Count == 0)
+            return;
+
+        var accounts = await _accountService.GetAccountsAsync();
+
+        if (!accounts.Any())
+            return;
+
+        MailAccount targetAccount = null;
+
+        if (accounts.Count == 1)
+        {
+            targetAccount = accounts[0];
+        }
+        else
+        {
+            targetAccount = await _dialogService.ShowAccountPickerDialogAsync(accounts);
+        }
+
+        if (targetAccount == null)
+            return;
+
+        await CreateNewMailForAsync(targetAccount, shareRequest);
+    }
+
     private async Task RecreateMenuItemsAsync()
     {
         await _menuRefreshSemaphore.WaitAsync().ConfigureAwait(false);

Wino.Mail.ViewModels/MailCategoryManagementPageViewModel.cs

@@ -0,0 +1,251 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using Wino.Core.Domain;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Entities.Shared;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.MailItem;
+using Wino.Core.Domain.Models.Navigation;
+using Wino.Core.Domain.Models.Synchronization;
+using Wino.Core.Requests.Category;
+using Wino.Core.Services;
+
+namespace Wino.Mail.ViewModels;
+
+public partial class MailCategoryManagementPageViewModel : MailBaseViewModel
+{
+    private readonly IMailCategoryService _mailCategoryService;
+    private readonly IAccountService _accountService;
+    private readonly IMailDialogService _dialogService;
+    private readonly IWinoRequestDelegator _winoRequestDelegator;
+
+    [ObservableProperty]
+    [NotifyPropertyChangedFor(nameof(CanRefresh))]
+    public partial MailAccount Account { get; set; }
+
+    public ObservableCollection<MailCategory> Categories { get; } = [];
+
+    public bool CanRefresh => Account?.ProviderType == MailProviderType.Outlook;
+    public bool HasCategories => Categories.Count > 0;
+
+    public MailCategoryManagementPageViewModel(
+        IMailCategoryService mailCategoryService,
+        IAccountService accountService,
+        IMailDialogService dialogService,
+        IWinoRequestDelegator winoRequestDelegator)
+    {
+        _mailCategoryService = mailCategoryService;
+        _accountService = accountService;
+        _dialogService = dialogService;
+        _winoRequestDelegator = winoRequestDelegator;
+    }
+
+    public override async void OnNavigatedTo(NavigationMode mode, object parameters)
+    {
+        base.OnNavigatedTo(mode, parameters);
+
+        if (parameters is not Guid accountId)
+            return;
+
+        Account = await _accountService.GetAccountAsync(accountId).ConfigureAwait(false);
+
+        if (Account != null)
+        {
+            await LoadCategoriesAsync().ConfigureAwait(false);
+        }
+    }
+
+    [RelayCommand]
+    private Task AddCategoryAsync()
+        => CreateOrUpdateCategoryAsync();
+
+    [RelayCommand]
+    private async Task RefreshCategoriesAsync()
+    {
+        if (!CanRefresh)
+            return;
+
+        var shouldContinue = await _dialogService.ShowConfirmationDialogAsync(
+            Translator.MailCategoryManagementPage_RefreshConfirmationMessage,
+            Translator.Buttons_Refresh,
+            Translator.Buttons_Refresh).ConfigureAwait(false);
+
+        if (!shouldContinue)
+            return;
+
+        await _mailCategoryService.DeleteCategoriesAsync(Account.Id).ConfigureAwait(false);
+        await SynchronizationManager.Instance.SynchronizeCategoriesAsync(Account.Id).ConfigureAwait(false);
+
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    public Task EditCategoryAsync(MailCategory category)
+        => CreateOrUpdateCategoryAsync(category);
+
+    public async Task DeleteCategoryAsync(MailCategory category)
+    {
+        if (category == null)
+            return;
+
+        var shouldDelete = await _dialogService.ShowConfirmationDialogAsync(
+            string.Format(Translator.MailCategoryManagementPage_DeleteConfirmationMessage, category.Name),
+            Translator.MailCategoryManagementPage_DeleteConfirmationTitle,
+            Translator.Buttons_Delete).ConfigureAwait(false);
+
+        if (!shouldDelete)
+            return;
+
+        var deleteRequest = await BuildDeleteCategoryRequestAsync(category).ConfigureAwait(false);
+        await _mailCategoryService.DeleteCategoryAsync(category.Id).ConfigureAwait(false);
+        await QueueOutlookCategoryRequestsAsync(deleteRequest).ConfigureAwait(false);
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    public async Task SetFavoriteAsync(MailCategory category, bool isFavorite)
+    {
+        if (category == null)
+            return;
+
+        await _mailCategoryService.ToggleFavoriteAsync(category.Id, isFavorite).ConfigureAwait(false);
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    private async Task CreateOrUpdateCategoryAsync(MailCategory existingCategory = null)
+    {
+        var dialogResult = await _dialogService.ShowEditMailCategoryDialogAsync(existingCategory).ConfigureAwait(false);
+        if (dialogResult == null)
+            return;
+
+        if (string.IsNullOrWhiteSpace(dialogResult.Name))
+        {
+            await _dialogService.ShowMessageAsync(
+                Translator.MailCategoryDialog_InvalidNameMessage,
+                Translator.MailCategoryDialog_InvalidNameTitle,
+                WinoCustomMessageDialogIcon.Warning).ConfigureAwait(false);
+            return;
+        }
+
+        var normalizedName = dialogResult.Name.Trim();
+        var categoryIdToExclude = existingCategory?.Id;
+        var alreadyExists = await _mailCategoryService.CategoryNameExistsAsync(Account.Id, normalizedName, categoryIdToExclude).ConfigureAwait(false);
+
+        if (alreadyExists)
+        {
+            await _dialogService.ShowMessageAsync(
+                Translator.MailCategoryDialog_DuplicateMessage,
+                Translator.MailCategoryDialog_DuplicateTitle,
+                WinoCustomMessageDialogIcon.Warning).ConfigureAwait(false);
+            return;
+        }
+
+        if (existingCategory == null)
+        {
+            var newCategory = new MailCategory
+            {
+                Id = Guid.NewGuid(),
+                MailAccountId = Account.Id,
+                Name = normalizedName,
+                BackgroundColorHex = dialogResult.BackgroundColorHex,
+                TextColorHex = dialogResult.TextColorHex,
+                Source = Account.ProviderType == MailProviderType.Outlook ? MailCategorySource.Outlook : MailCategorySource.Local
+            };
+
+            await _mailCategoryService.CreateCategoryAsync(newCategory).ConfigureAwait(false);
+
+            if (Account.ProviderType == MailProviderType.Outlook)
+            {
+                await _winoRequestDelegator.ExecuteAsync(Account.Id, [new MailCategoryCreateRequest(newCategory)]).ConfigureAwait(false);
+            }
+        }
+        else
+        {
+            var previousName = existingCategory.Name;
+            var previousRemoteId = existingCategory.RemoteId;
+
+            existingCategory.Name = normalizedName;
+            existingCategory.BackgroundColorHex = dialogResult.BackgroundColorHex;
+            existingCategory.TextColorHex = dialogResult.TextColorHex;
+
+            await _mailCategoryService.UpdateCategoryAsync(existingCategory).ConfigureAwait(false);
+
+            if (Account.ProviderType == MailProviderType.Outlook)
+            {
+                if (string.IsNullOrWhiteSpace(previousRemoteId))
+                {
+                    await _winoRequestDelegator.ExecuteAsync(Account.Id, [new MailCategoryCreateRequest(existingCategory)]).ConfigureAwait(false);
+                }
+                else
+                {
+                    var affectedMessages = await BuildAffectedMessageTargetsAsync(existingCategory.Id).ConfigureAwait(false);
+                    var updateRequest = new MailCategoryUpdateRequest(existingCategory, previousName, previousRemoteId, affectedMessages);
+                    await _winoRequestDelegator.ExecuteAsync(Account.Id, [updateRequest]).ConfigureAwait(false);
+                }
+            }
+        }
+
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    private async Task<MailCategoryDeleteRequest> BuildDeleteCategoryRequestAsync(MailCategory category)
+    {
+        if (category == null || Account?.ProviderType != MailProviderType.Outlook)
+            return null;
+
+        var mailCopies = await _mailCategoryService.GetMailCopiesForCategoryAsync(category.Id).ConfigureAwait(false);
+        var affectedMessages = new List<MailCategoryMessageUpdateTarget>();
+
+        foreach (var mailCopy in mailCopies.Where(a => !string.IsNullOrWhiteSpace(a.Id)))
+        {
+            var remainingNames = await _mailCategoryService.GetCategoryNamesForMailAsync(mailCopy.UniqueId).ConfigureAwait(false);
+            var categoryNames = remainingNames
+                .Where(a => !string.Equals(a, category.Name, StringComparison.OrdinalIgnoreCase))
+                .ToList();
+
+            affectedMessages.Add(new MailCategoryMessageUpdateTarget(mailCopy.Id, categoryNames));
+        }
+
+        return new MailCategoryDeleteRequest(category, category.RemoteId, affectedMessages);
+    }
+
+    private async Task<IReadOnlyList<MailCategoryMessageUpdateTarget>> BuildAffectedMessageTargetsAsync(Guid categoryId)
+    {
+        var mailCopies = await _mailCategoryService.GetMailCopiesForCategoryAsync(categoryId).ConfigureAwait(false);
+        var affectedMessages = new List<MailCategoryMessageUpdateTarget>();
+
+        foreach (var mailCopy in mailCopies.Where(a => !string.IsNullOrWhiteSpace(a.Id)))
+        {
+            var categoryNames = await _mailCategoryService.GetCategoryNamesForMailAsync(mailCopy.UniqueId).ConfigureAwait(false);
+            affectedMessages.Add(new MailCategoryMessageUpdateTarget(mailCopy.Id, categoryNames));
+        }
+
+        return affectedMessages;
+    }
+
+    private Task QueueOutlookCategoryRequestsAsync(params IRequestBase[] requests)
+        => Account?.ProviderType == MailProviderType.Outlook && requests.Any(a => a != null)
+            ? _winoRequestDelegator.ExecuteAsync(Account.Id, requests.Where(a => a != null))
+            : Task.CompletedTask;
+
+    private async Task LoadCategoriesAsync()
+    {
+        var categories = await _mailCategoryService.GetCategoriesAsync(Account.Id).ConfigureAwait(false);
+
+        await ExecuteUIThread(() =>
+        {
+            Categories.Clear();
+
+            foreach (var category in categories)
+            {
+                Categories.Add(category);
+            }
+
+            OnPropertyChanged(nameof(HasCategories));
+        });
+    }
+}

Wino.Mail.ViewModels/MailListPageViewModel.cs

@@ -23,7 +23,7 @@ using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.Domain.Models.Menus;
 using Wino.Core.Domain.Models.Navigation;
 using Wino.Core.Domain.Models.Reader;
-using Wino.Core.Domain.Models.Synchronization;
+using Wino.Core.Requests.Mail;
 using Wino.Core.Services;
 using Wino.Mail.ViewModels.Collections;
 using Wino.Mail.ViewModels.Data;
@@ -77,6 +77,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     private readonly INotificationBuilder _notificationBuilder;
     private readonly IFolderService _folderService;
     private readonly IContextMenuItemService _contextMenuItemService;
+    private readonly IMailCategoryService _mailCategoryService;
     private readonly IWinoRequestDelegator _winoRequestDelegator;
     private readonly IKeyPressService _keyPressService;
     private readonly IWinoLogger _winoLogger;
@@ -156,6 +157,8 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     [ObservableProperty]
     [NotifyPropertyChangedFor(nameof(CanSynchronize))]
     [NotifyPropertyChangedFor(nameof(IsFolderSynchronizationEnabled))]
+    [NotifyPropertyChangedFor(nameof(IsCategoryView))]
+    [NotifyPropertyChangedFor(nameof(IsSyncButtonVisible))]
     public partial IBaseFolderMenuItem ActiveFolder { get; set; }
 
     [ObservableProperty]
@@ -172,6 +175,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
                                  INotificationBuilder notificationBuilder,
                                  IFolderService folderService,
                                  IContextMenuItemService contextMenuItemService,
+                                 IMailCategoryService mailCategoryService,
                                  IWinoRequestDelegator winoRequestDelegator,
                                  IKeyPressService keyPressService,
                                  IPreferencesService preferencesService,
@@ -185,6 +189,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         _mimeFileService = mimeFileService;
         _folderService = folderService;
         _contextMenuItemService = contextMenuItemService;
+        _mailCategoryService = mailCategoryService;
         _winoRequestDelegator = winoRequestDelegator;
         _keyPressService = keyPressService;
 
@@ -277,9 +282,11 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
     }
 
-    public bool CanSynchronize => !IsAccountSynchronizerInSynchronization && IsFolderSynchronizationEnabled;
+    public bool CanSynchronize => !IsCategoryView && !IsAccountSynchronizerInSynchronization && IsFolderSynchronizationEnabled;
     public bool IsFolderSynchronizationEnabled => ActiveFolder?.IsSynchronizationEnabled ?? false;
     public bool IsArchiveSpecialFolder => ActiveFolder?.SpecialFolderType == SpecialFolderType.Archive;
+    public bool IsCategoryView => ActiveFolder is IMailCategoryMenuItem or IMergedMailCategoryMenuItem;
+    public bool IsSyncButtonVisible => !IsCategoryView;
 
     public string SelectedMessageText => IsDragInProgress
         ? string.Format(Translator.MailsDragging, DraggingItemsCount)
@@ -396,9 +403,12 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
         else
         {
+            if (IsCategoryView)
+            {
+                PivotFolders.Add(new FolderPivotViewModel(ActiveFolder.FolderName, null));
+            }
             // Merged folders don't support focused feature.
-
-            if (ActiveFolder is IMergedAccountFolderMenuItem)
+            else if (ActiveFolder is IMergedAccountFolderMenuItem)
             {
                 PivotFolders.Add(new FolderPivotViewModel(ActiveFolder.FolderName, null));
             }
@@ -475,26 +485,29 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     {
         if (!CanSynchronize) return;
 
+        _notificationBuilder.CreateNotificationsAsync(MailCollection.SelectedItems.Select(a => a.MailCopy));
+        return;
+
         // Only synchronize listed folders.
 
         // When doing linked inbox sync, we need to save the sync id to report progress back only once.
         // Otherwise, we will report progress for each folder and that's what we don't want.
 
-        trackingSynchronizationId = Guid.NewGuid();
-        completedTrackingSynchronizationCount = 0;
+        //trackingSynchronizationId = Guid.NewGuid();
+        //completedTrackingSynchronizationCount = 0;
 
-        foreach (var folder in ActiveFolder.HandlingFolders)
-        {
-            var options = new MailSynchronizationOptions()
-            {
-                AccountId = folder.MailAccountId,
-                Type = MailSynchronizationType.CustomFolders,
-                SynchronizationFolderIds = [folder.Id],
-                GroupedSynchronizationTrackingId = trackingSynchronizationId
-            };
+        //foreach (var folder in ActiveFolder.HandlingFolders)
+        //{
+        //    var options = new MailSynchronizationOptions()
+        //    {
+        //        AccountId = folder.MailAccountId,
+        //        Type = MailSynchronizationType.CustomFolders,
+        //        SynchronizationFolderIds = [folder.Id],
+        //        GroupedSynchronizationTrackingId = trackingSynchronizationId
+        //    };
 
-            Messenger.Send(new NewMailSynchronizationRequested(options));
-        }
+        //    Messenger.Send(new NewMailSynchronizationRequested(options));
+        //}
     }
 
     [RelayCommand]
@@ -545,7 +558,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     [RelayCommand]
     private async Task EnableFolderSynchronizationAsync()
     {
-        if (ActiveFolder == null) return;
+        if (ActiveFolder == null || IsCategoryView) return;
 
         foreach (var folder in ActiveFolder.HandlingFolders)
         {
@@ -561,13 +574,9 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         Debug.WriteLine("Loading more...");
         await ExecuteUIThread(() => { IsInitializingFolder = true; });
 
-        var initializationOptions = new MailListInitializationOptions(ActiveFolder.HandlingFolders,
-                                                                      SelectedFilterOption.Type,
-                                                                      SelectedSortingOption.Type,
-                                                                      PreferencesService.IsThreadingEnabled,
-                                                                      SelectedFolderPivot.IsFocused,
-                                                                      IsInSearchMode ? SearchQuery : string.Empty,
-                                                                      MailCollection.MailCopyIdHashSet);
+        var initializationOptions = CreateInitializationOptions(
+            IsInSearchMode ? SearchQuery : string.Empty,
+            MailCollection.MailCopyIdHashSet);
 
         var items = await _mailService.FetchMailsAsync(initializationOptions).ConfigureAwait(false);
 
@@ -674,6 +683,60 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     public IEnumerable<MailOperationMenuItem> GetAvailableMailActions(IEnumerable<MailItemViewModel> contextMailItems)
         => _contextMenuItemService.GetMailItemContextMenuActions(contextMailItems.Select(a => a.MailCopy));
 
+    public async Task<(IReadOnlyList<MailCategory> Categories, IReadOnlyCollection<Guid> AssignedCategoryIds)> GetAvailableCategoriesAsync(IEnumerable<MailItemViewModel> targetItems)
+    {
+        var targetList = targetItems?.Where(a => a?.MailCopy?.AssignedAccount != null).ToList() ?? [];
+        if (targetList.Count == 0)
+            return ([], []);
+
+        var accountIds = targetList.Select(a => a.MailCopy.AssignedAccount.Id).Distinct().ToList();
+        if (accountIds.Count != 1)
+            return ([], []);
+
+        var accountId = accountIds[0];
+        var uniqueIds = targetList.Select(a => a.MailCopy.UniqueId).Distinct().ToList();
+
+        var categories = await _mailCategoryService.GetCategoriesAsync(accountId).ConfigureAwait(false);
+        var assignedCategoryIds = await _mailCategoryService.GetAssignedCategoryIdsForAllAsync(uniqueIds).ConfigureAwait(false);
+
+        return (categories, assignedCategoryIds);
+    }
+
+    public async Task ToggleCategoryAssignmentAsync(MailCategory category, IEnumerable<MailItemViewModel> targetItems, bool isAssignedToAll)
+    {
+        var targetList = targetItems?.Where(a => a?.MailCopy?.AssignedAccount != null).ToList() ?? [];
+        if (category == null || targetList.Count == 0)
+            return;
+
+        var accountIds = targetList.Select(a => a.MailCopy.AssignedAccount.Id).Distinct().ToList();
+        if (accountIds.Count != 1)
+            return;
+
+        var accountId = accountIds[0];
+        var uniqueIds = targetList.Select(a => a.MailCopy.UniqueId).Distinct().ToList();
+
+        if (isAssignedToAll)
+        {
+            await _mailCategoryService.UnassignCategoryAsync(category.Id, uniqueIds).ConfigureAwait(false);
+        }
+        else
+        {
+            await _mailCategoryService.AssignCategoryAsync(category.Id, uniqueIds).ConfigureAwait(false);
+        }
+
+        if (targetList.First().MailCopy.AssignedAccount.ProviderType != MailProviderType.Outlook)
+            return;
+
+        var requests = new List<IRequestBase>();
+        foreach (var mailItem in targetList.Select(a => a.MailCopy).DistinctBy(a => a.UniqueId))
+        {
+            var categoryNames = await _mailCategoryService.GetCategoryNamesForMailAsync(mailItem.UniqueId).ConfigureAwait(false);
+            requests.Add(new MailCategoryAssignmentRequest(mailItem, category.Id, category.Name, categoryNames, !isAssignedToAll));
+        }
+
+        await _winoRequestDelegator.ExecuteAsync(accountId, requests).ConfigureAwait(false);
+    }
+
     private bool ShouldPreventItemAdd(MailCopy mailItem)
     {
         bool condition = mailItem.IsRead
@@ -691,7 +754,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         => ActiveFolder?.SpecialFolderType == SpecialFolderType.Draft;
 
     private bool BelongsToActiveFolder(MailCopy mailItem)
-        => mailItem?.AssignedFolder != null && ActiveFolder?.HandlingFolders?.Any(a => a.Id == mailItem.AssignedFolder.Id) == true;
+        => !IsCategoryView && mailItem?.AssignedFolder != null && ActiveFolder?.HandlingFolders?.Any(a => a.Id == mailItem.AssignedFolder.Id) == true;
 
     private bool ShouldIncludeByThread(MailCopy mailItem)
         => PreferencesService.IsThreadingEnabled
@@ -1069,6 +1132,38 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
     }
 
+    private MailListInitializationOptions CreateInitializationOptions(
+        string searchQuery,
+        System.Collections.Concurrent.ConcurrentDictionary<Guid, bool> existingUniqueIds,
+        List<MailCopy> preFetchedMailCopies = null,
+        bool deduplicateByServerId = false)
+    {
+        var options = new MailListInitializationOptions(ActiveFolder.HandlingFolders,
+                                                        SelectedFilterOption.Type,
+                                                        SelectedSortingOption.Type,
+                                                        PreferencesService.IsThreadingEnabled,
+                                                        SelectedFolderPivot.IsFocused,
+                                                        searchQuery,
+                                                        existingUniqueIds,
+                                                        preFetchedMailCopies,
+                                                        DeduplicateByServerId: deduplicateByServerId);
+
+        if (!IsCategoryView)
+            return options;
+
+        var categoryIds = ActiveFolder switch
+        {
+            IMailCategoryMenuItem singleCategoryMenuItem => new List<Guid> { singleCategoryMenuItem.MailCategory.Id },
+            IMergedMailCategoryMenuItem mergedCategoryMenuItem => mergedCategoryMenuItem.Categories.Select(a => a.Id).ToList(),
+            _ => []
+        };
+
+        return options with
+        {
+            CategoryIds = categoryIds
+        };
+    }
+
     [RelayCommand]
     private async Task PerformOnlineSearchAsync()
     {
@@ -1218,15 +1313,11 @@ public partial class MailListPageViewModel : MailBaseViewModel,
                 }
             }
 
-            var initializationOptions = new MailListInitializationOptions(ActiveFolder.HandlingFolders,
-                                                                          SelectedFilterOption.Type,
-                                                                          SelectedSortingOption.Type,
-                                                                          PreferencesService.IsThreadingEnabled,
-                                                                          SelectedFolderPivot.IsFocused,
-                                                                          isDoingOnlineSearch ? string.Empty : SearchQuery,
-                                                                          MailCollection.MailCopyIdHashSet,
-                                                                          onlineSearchItems,
-                                                                          DeduplicateByServerId: isDoingOnlineSearch);
+            var initializationOptions = CreateInitializationOptions(
+                isDoingOnlineSearch ? string.Empty : SearchQuery,
+                MailCollection.MailCopyIdHashSet,
+                onlineSearchItems,
+                isDoingOnlineSearch);
 
             items = await _mailService.FetchMailsAsync(initializationOptions, cancellationToken).ConfigureAwait(false);
 

Wino.Mail.ViewModels/MailNotificationSettingsPageViewModel.cs

@@ -0,0 +1,135 @@
+using System.Collections.ObjectModel;
+using System.Linq;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain;
+
+namespace Wino.Mail.ViewModels;
+
+public partial class MailNotificationSettingsPageViewModel : MailBaseViewModel
+{
+    private static readonly MailOperation[] SupportedMailNotificationActions =
+    [
+        MailOperation.MarkAsRead,
+        MailOperation.SoftDelete,
+        MailOperation.MoveToJunk,
+        MailOperation.Archive,
+        MailOperation.Reply,
+        MailOperation.ReplyAll,
+        MailOperation.Forward
+    ];
+
+    private readonly IPreferencesService _preferencesService;
+    private bool _isUpdatingSelection;
+    private bool _isLoaded;
+
+    public ObservableCollection<MailNotificationActionOption> AvailableNotificationActions { get; } = [];
+
+    [ObservableProperty]
+    public partial MailNotificationActionOption SelectedFirstAction { get; set; }
+
+    [ObservableProperty]
+    public partial MailNotificationActionOption SelectedSecondAction { get; set; }
+
+    public MailNotificationSettingsPageViewModel(IPreferencesService preferencesService)
+    {
+        _preferencesService = preferencesService;
+
+        foreach (var action in SupportedMailNotificationActions)
+        {
+            AvailableNotificationActions.Add(new MailNotificationActionOption(action, GetOperationDisplayText(action)));
+        }
+
+        InitializeSelections();
+        _isLoaded = true;
+    }
+
+    partial void OnSelectedFirstActionChanged(MailNotificationActionOption value)
+    {
+        if (!_isLoaded || _isUpdatingSelection || value == null)
+            return;
+
+        EnsureDistinctSelections(changedSelection: value, isFirstSelection: true);
+        _preferencesService.FirstMailNotificationAction = value.Operation;
+    }
+
+    partial void OnSelectedSecondActionChanged(MailNotificationActionOption value)
+    {
+        if (!_isLoaded || _isUpdatingSelection || value == null)
+            return;
+
+        EnsureDistinctSelections(changedSelection: value, isFirstSelection: false);
+        _preferencesService.SecondMailNotificationAction = value.Operation;
+    }
+
+    private void InitializeSelections()
+    {
+        var firstAction = ResolveSupportedAction(_preferencesService.FirstMailNotificationAction, MailOperation.MarkAsRead);
+        var secondAction = ResolveSupportedAction(_preferencesService.SecondMailNotificationAction, MailOperation.SoftDelete);
+
+        if (secondAction == firstAction)
+        {
+            secondAction = GetFallbackDistinctAction(firstAction);
+        }
+
+        SelectedFirstAction = GetOption(firstAction);
+        SelectedSecondAction = GetOption(secondAction);
+
+        _preferencesService.FirstMailNotificationAction = firstAction;
+        _preferencesService.SecondMailNotificationAction = secondAction;
+    }
+
+    private void EnsureDistinctSelections(MailNotificationActionOption changedSelection, bool isFirstSelection)
+    {
+        var otherSelection = isFirstSelection ? SelectedSecondAction : SelectedFirstAction;
+        if (otherSelection?.Operation != changedSelection.Operation)
+            return;
+
+        _isUpdatingSelection = true;
+
+        var fallbackAction = GetFallbackDistinctAction(changedSelection.Operation);
+        var fallbackOption = GetOption(fallbackAction);
+
+        if (isFirstSelection)
+        {
+            SelectedSecondAction = fallbackOption;
+            _preferencesService.SecondMailNotificationAction = fallbackAction;
+        }
+        else
+        {
+            SelectedFirstAction = fallbackOption;
+            _preferencesService.FirstMailNotificationAction = fallbackAction;
+        }
+
+        _isUpdatingSelection = false;
+    }
+
+    private MailNotificationActionOption GetOption(MailOperation action)
+        => AvailableNotificationActions.First(option => option.Operation == action);
+
+    private static MailOperation ResolveSupportedAction(MailOperation action, MailOperation fallbackAction)
+        => SupportedMailNotificationActions.Contains(action) ? action : fallbackAction;
+
+    private static MailOperation GetFallbackDistinctAction(MailOperation excludedAction)
+        => SupportedMailNotificationActions.First(action => action != excludedAction);
+
+    private static string GetOperationDisplayText(MailOperation action)
+        => action switch
+        {
+            MailOperation.MarkAsRead => Translator.MailOperation_MarkAsRead,
+            MailOperation.SoftDelete => Translator.MailOperation_Delete,
+            MailOperation.MoveToJunk => Translator.MailOperation_MarkAsJunk,
+            MailOperation.Archive => Translator.MailOperation_Archive,
+            MailOperation.Reply => Translator.MailOperation_Reply,
+            MailOperation.ReplyAll => Translator.MailOperation_ReplyAll,
+            MailOperation.Forward => Translator.MailOperation_Forward,
+            _ => action.ToString()
+        };
+}
+
+public sealed class MailNotificationActionOption(MailOperation operation, string displayText)
+{
+    public MailOperation Operation { get; } = operation;
+    public string DisplayText { get; } = displayText;
+}

Wino.Mail.ViewModels/ProviderSelectionPageViewModel.cs

@@ -6,6 +6,7 @@ using CommunityToolkit.Mvvm.Messaging;
 using Wino.Core.Domain;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.Navigation;
 using Wino.Core.ViewModels.Data;
 using Wino.Mail.ViewModels.Data;
@@ -22,13 +23,26 @@ public partial class ProviderSelectionPageViewModel : MailBaseViewModel
 
     public List<IProviderDetail> Providers { get; private set; } = [];
     public List<AppColorViewModel> AvailableColors { get; private set; } = [];
+    public List<InitialSynchronizationRangeOption> InitialSynchronizationRanges { get; } =
+    [
+        new(InitialSynchronizationRange.ThreeMonths, Translator.AccountCreation_InitialSynchronization_3Months),
+        new(InitialSynchronizationRange.SixMonths, Translator.AccountCreation_InitialSynchronization_6Months),
+        new(InitialSynchronizationRange.NineMonths, Translator.AccountCreation_InitialSynchronization_9Months),
+        new(InitialSynchronizationRange.OneYear, Translator.AccountCreation_InitialSynchronization_Year),
+        new(InitialSynchronizationRange.Everything, Translator.AccountCreation_InitialSynchronization_Everything)
+    ];
 
     [ObservableProperty]
     public partial IProviderDetail SelectedProvider { get; set; }
 
     [ObservableProperty]
+    [NotifyPropertyChangedFor(nameof(IsColorSelected))]
     public partial AppColorViewModel SelectedColor { get; set; }
 
+    [ObservableProperty]
+    [NotifyPropertyChangedFor(nameof(IsInitialSynchronizationWarningVisible))]
+    public partial InitialSynchronizationRangeOption SelectedInitialSynchronizationRange { get; set; }
+
     [ObservableProperty]
     public partial string AccountName { get; set; }
 
@@ -36,6 +50,7 @@ public partial class ProviderSelectionPageViewModel : MailBaseViewModel
     public partial bool CanProceed { get; set; }
 
     public bool IsColorSelected => SelectedColor != null;
+    public bool IsInitialSynchronizationWarningVisible => SelectedInitialSynchronizationRange?.IsEverything == true;
 
     public ProviderSelectionPageViewModel(
         IProviderService providerService,
@@ -45,6 +60,7 @@ public partial class ProviderSelectionPageViewModel : MailBaseViewModel
         _providerService = providerService;
         _themeService = themeService;
         WizardContext = wizardContext;
+        SelectedInitialSynchronizationRange = InitialSynchronizationRanges.First(option => option.Range == InitialSynchronizationRange.SixMonths);
     }
 
     public override void OnNavigatedTo(NavigationMode mode, object parameters)
@@ -56,6 +72,10 @@ public partial class ProviderSelectionPageViewModel : MailBaseViewModel
             .Select(hex => new AppColorViewModel(hex))
             .ToList();
 
+        SelectedInitialSynchronizationRange = InitialSynchronizationRanges
+            .FirstOrDefault(option => option.Range == WizardContext.SelectedInitialSynchronizationRange)
+            ?? InitialSynchronizationRanges.First(option => option.Range == InitialSynchronizationRange.SixMonths);
+
         // Restore from wizard context if navigating back
         if (WizardContext.SelectedProvider != null)
         {
@@ -71,9 +91,12 @@ public partial class ProviderSelectionPageViewModel : MailBaseViewModel
         Validate();
     }
 
-    partial void OnSelectedProviderChanged(IProviderDetail value) => Validate();
+    partial void OnSelectedProviderChanged(IProviderDetail value)
+    {
+        Validate();
+    }
+
     partial void OnAccountNameChanged(string value) => Validate();
-    partial void OnSelectedColorChanged(AppColorViewModel value) => OnPropertyChanged(nameof(IsColorSelected));
 
     [RelayCommand]
     private void ClearColor() => SelectedColor = null;
@@ -92,6 +115,7 @@ public partial class ProviderSelectionPageViewModel : MailBaseViewModel
         WizardContext.SelectedProvider = SelectedProvider;
         WizardContext.AccountName = AccountName?.Trim();
         WizardContext.AccountColorHex = SelectedColor?.Hex ?? string.Empty;
+        WizardContext.SelectedInitialSynchronizationRange = SelectedInitialSynchronizationRange?.Range ?? InitialSynchronizationRange.SixMonths;
 
         if (WizardContext.IsGenericImap)
         {

Wino.Mail.WinUI/Activation/AppNotificationActivationBuffer.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Windows.AppNotifications;
+
+namespace Wino.Mail.WinUI.Activation;
+
+internal sealed record BufferedAppNotificationActivation(string Argument, IReadOnlyDictionary<string, string>? UserInput);
+
+internal sealed class AppNotificationActivationBuffer
+{
+    private readonly ConcurrentQueue<BufferedAppNotificationActivation> _pendingActivations = new();
+    private readonly SemaphoreSlim _pendingSignal = new(0);
+
+    public void Enqueue(AppNotificationActivatedEventArgs args)
+    {
+        var copiedUserInput = args.UserInput == null
+            ? null
+            : new Dictionary<string, string>(args.UserInput, StringComparer.Ordinal);
+
+        _pendingActivations.Enqueue(new BufferedAppNotificationActivation(args.Argument, copiedUserInput));
+        _pendingSignal.Release();
+    }
+
+    public bool TryDequeue(out BufferedAppNotificationActivation activation)
+        => _pendingActivations.TryDequeue(out activation!);
+
+    public async Task<BufferedAppNotificationActivation?> WaitAsync(TimeSpan timeout, CancellationToken cancellationToken = default)
+    {
+        if (!_pendingActivations.IsEmpty && TryDequeue(out var queuedActivation))
+            return queuedActivation;
+
+        if (!await _pendingSignal.WaitAsync(timeout, cancellationToken))
+            return null;
+
+        return TryDequeue(out var activation) ? activation : null;
+    }
+}

Wino.Mail.WinUI/Activation/CalendarEntryBootstrapActivation.cs

@@ -0,0 +1,207 @@
+using System;
+using System.IO;
+using System.Linq;
+using Microsoft.Windows.AppLifecycle;
+using Windows.ApplicationModel;
+using Windows.ApplicationModel.Activation;
+using Windows.Storage;
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Mail.WinUI.Activation;
+
+internal enum PendingBootstrapActivationKind
+{
+    Launch,
+    Protocol,
+    File
+}
+
+internal sealed class PendingBootstrapActivation
+{
+    public PendingBootstrapActivationKind Kind { get; init; }
+    public WinoApplicationMode Mode { get; init; } = WinoApplicationMode.Mail;
+    public string? LaunchArguments { get; init; }
+    public string? TileId { get; init; }
+    public string? ProtocolUri { get; init; }
+    public string[] FilePaths { get; init; } = [];
+    public DateTimeOffset CreatedAtUtc { get; init; } = DateTimeOffset.UtcNow;
+}
+
+internal static class CalendarEntryBootstrapActivation
+{
+    private const string PendingActivationKey = "PendingCalendarEntryBootstrapActivation";
+    private const string KindKey = "Kind";
+    private const string ModeKey = "Mode";
+    private const string LaunchArgumentsKey = "LaunchArguments";
+    private const string TileIdKey = "TileId";
+    private const string ProtocolUriKey = "ProtocolUri";
+    private const string FilePathsKey = "FilePaths";
+    private const string CreatedAtUtcKey = "CreatedAtUtc";
+    private static readonly TimeSpan PendingActivationLifetime = TimeSpan.FromMinutes(1);
+
+    public static bool ShouldBootstrapToMailHost(AppActivationArguments activationArgs)
+        => TryCreatePendingActivation(activationArgs, out _);
+
+    public static bool QueuePendingActivation(AppActivationArguments activationArgs)
+    {
+        if (!TryCreatePendingActivation(activationArgs, out var pendingActivation))
+            return false;
+
+        ApplicationData.Current.LocalSettings.Values[PendingActivationKey] = CreateCompositeValue(pendingActivation!);
+        return true;
+    }
+
+    public static void ClearPendingActivation()
+        => ApplicationData.Current.LocalSettings.Values.Remove(PendingActivationKey);
+
+    public static PendingBootstrapActivation? ConsumePendingActivation()
+    {
+        if (!ApplicationData.Current.LocalSettings.Values.TryGetValue(PendingActivationKey, out var pendingActivationValue) ||
+            pendingActivationValue is not ApplicationDataCompositeValue compositeValue)
+        {
+            return null;
+        }
+
+        ClearPendingActivation();
+
+        try
+        {
+            var pendingActivation = ParseCompositeValue(compositeValue);
+            if (pendingActivation == null)
+                return null;
+
+            if (DateTimeOffset.UtcNow - pendingActivation.CreatedAtUtc > PendingActivationLifetime)
+                return null;
+
+            return pendingActivation;
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private static ApplicationDataCompositeValue CreateCompositeValue(PendingBootstrapActivation pendingActivation)
+    {
+        var compositeValue = new ApplicationDataCompositeValue
+        {
+            [KindKey] = pendingActivation.Kind.ToString(),
+            [ModeKey] = pendingActivation.Mode.ToString(),
+            [LaunchArgumentsKey] = pendingActivation.LaunchArguments ?? string.Empty,
+            [TileIdKey] = pendingActivation.TileId ?? string.Empty,
+            [ProtocolUriKey] = pendingActivation.ProtocolUri ?? string.Empty,
+            [FilePathsKey] = string.Join("\n", pendingActivation.FilePaths),
+            [CreatedAtUtcKey] = pendingActivation.CreatedAtUtc.ToString("o")
+        };
+
+        return compositeValue;
+    }
+
+    private static PendingBootstrapActivation? ParseCompositeValue(ApplicationDataCompositeValue compositeValue)
+    {
+        if (!Enum.TryParse(compositeValue[KindKey]?.ToString(), ignoreCase: true, out PendingBootstrapActivationKind kind) ||
+            !Enum.TryParse(compositeValue[ModeKey]?.ToString(), ignoreCase: true, out WinoApplicationMode mode) ||
+            !DateTimeOffset.TryParse(compositeValue[CreatedAtUtcKey]?.ToString(), out var createdAtUtc))
+        {
+            return null;
+        }
+
+        return new PendingBootstrapActivation
+        {
+            Kind = kind,
+            Mode = mode,
+            LaunchArguments = GetOptionalCompositeString(compositeValue, LaunchArgumentsKey),
+            TileId = GetOptionalCompositeString(compositeValue, TileIdKey),
+            ProtocolUri = GetOptionalCompositeString(compositeValue, ProtocolUriKey),
+            FilePaths = GetOptionalCompositeString(compositeValue, FilePathsKey)?
+                .Split(['\n'], StringSplitOptions.RemoveEmptyEntries)
+                .Distinct(StringComparer.OrdinalIgnoreCase)
+                .ToArray() ?? [],
+            CreatedAtUtc = createdAtUtc
+        };
+    }
+
+    private static string? GetOptionalCompositeString(ApplicationDataCompositeValue compositeValue, string key)
+    {
+        if (!compositeValue.TryGetValue(key, out var value))
+            return null;
+
+        var stringValue = value?.ToString();
+        return string.IsNullOrWhiteSpace(stringValue) ? null : stringValue;
+    }
+
+    public static bool LaunchMailHost()
+    {
+        var mailAppUserModelId = AppEntryConstants.GetAppUserModelId(WinoApplicationMode.Mail);
+        var appEntries = Package.Current.GetAppListEntriesAsync().AsTask().GetAwaiter().GetResult();
+        var mailEntry = appEntries.FirstOrDefault(entry =>
+            string.Equals(entry.AppUserModelId, mailAppUserModelId, StringComparison.OrdinalIgnoreCase));
+
+        return mailEntry != null && mailEntry.LaunchAsync().AsTask().GetAwaiter().GetResult();
+    }
+
+    private static bool TryCreatePendingActivation(AppActivationArguments activationArgs, out PendingBootstrapActivation? pendingActivation)
+    {
+        pendingActivation = null;
+
+        if (activationArgs.Kind == ExtendedActivationKind.Launch &&
+            activationArgs.Data is ILaunchActivatedEventArgs launchArgs)
+        {
+            var resolvedMode = AppModeActivationResolver.Resolve(launchArgs.Arguments, launchArgs.TileId, Environment.CommandLine);
+            if (resolvedMode != WinoApplicationMode.Calendar)
+                return false;
+
+            pendingActivation = new PendingBootstrapActivation
+            {
+                Kind = PendingBootstrapActivationKind.Launch,
+                Mode = resolvedMode,
+                LaunchArguments = launchArgs.Arguments,
+                TileId = launchArgs.TileId
+            };
+
+            return true;
+        }
+
+        if (activationArgs.Kind == ExtendedActivationKind.Protocol &&
+            activationArgs.Data is IProtocolActivatedEventArgs protocolArgs &&
+            protocolArgs.Uri != null &&
+            (string.Equals(protocolArgs.Uri.Scheme, "webcal", StringComparison.OrdinalIgnoreCase) ||
+             string.Equals(protocolArgs.Uri.Scheme, "webcals", StringComparison.OrdinalIgnoreCase)))
+        {
+            pendingActivation = new PendingBootstrapActivation
+            {
+                Kind = PendingBootstrapActivationKind.Protocol,
+                Mode = WinoApplicationMode.Calendar,
+                ProtocolUri = protocolArgs.Uri.AbsoluteUri
+            };
+
+            return true;
+        }
+
+        if (activationArgs.Kind == ExtendedActivationKind.File &&
+            activationArgs.Data is IFileActivatedEventArgs fileArgs)
+        {
+            var filePaths = fileArgs.Files?
+                .OfType<IStorageItem>()
+                .Where(item => string.Equals(Path.GetExtension(item.Path), ".ics", StringComparison.OrdinalIgnoreCase))
+                .Select(item => item.Path)
+                .Where(path => !string.IsNullOrWhiteSpace(path))
+                .Distinct(StringComparer.OrdinalIgnoreCase)
+                .ToArray();
+
+            if (filePaths == null || filePaths.Length == 0)
+                return false;
+
+            pendingActivation = new PendingBootstrapActivation
+            {
+                Kind = PendingBootstrapActivationKind.File,
+                Mode = WinoApplicationMode.Calendar,
+                FilePaths = filePaths
+            };
+
+            return true;
+        }
+
+        return false;
+    }
+}

Wino.Mail.WinUI/Activation/ToastActivationResolver.cs

@@ -41,9 +41,14 @@ internal static class ToastActivationResolver
             return calendarAction == Constants.ToastCalendarNavigateAction;
         }
 
+        if (toastArguments.TryGetValue(Constants.ToastDismissActionKey, out string _))
+        {
+            return false;
+        }
+
         if (toastArguments.TryGetValue(Constants.ToastActionKey, out MailOperation mailAction))
         {
-            return mailAction == MailOperation.Navigate;
+            return mailAction is MailOperation.Navigate or MailOperation.Reply or MailOperation.ReplyAll or MailOperation.Forward;
         }
 
         return true;
@@ -52,5 +57,6 @@ internal static class ToastActivationResolver
     private static bool ContainsKnownToastKey(NotificationArguments toastArguments)
         => toastArguments.TryGetValue(Constants.ToastStoreUpdateActionKey, out string _) ||
            toastArguments.TryGetValue(Constants.ToastCalendarActionKey, out string _) ||
+           toastArguments.TryGetValue(Constants.ToastDismissActionKey, out string _) ||
            toastArguments.TryGetValue(Constants.ToastActionKey, out string _);
 }

Wino.Mail.WinUI/App.xaml.cs

@@ -15,6 +15,9 @@ using Microsoft.Windows.AppLifecycle;
 using Microsoft.Windows.AppNotifications;
 using MimeKit.Cryptography;
 using Windows.ApplicationModel.Activation;
+using Windows.ApplicationModel.DataTransfer;
+using Windows.ApplicationModel.DataTransfer.ShareTarget;
+using Windows.Storage;
 using Wino.Calendar.ViewModels;
 using Wino.Calendar.ViewModels.Interfaces;
 using Wino.Core;
@@ -22,6 +25,8 @@ using Wino.Core.Domain;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.Calendar;
+using Wino.Core.Domain.Models.Common;
+using Wino.Core.Domain.Models.Launch;
 using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.Domain.Models.Navigation;
 using Wino.Core.Domain.Models.Synchronization;
@@ -30,6 +35,8 @@ using Wino.Mail.Services;
 using Wino.Mail.ViewModels;
 using Wino.Mail.ViewModels.Data;
 using Wino.Mail.WinUI.Activation;
+using Wino.Mail.WinUI.Extensions;
+using Wino.Mail.WinUI.Helpers;
 using Wino.Mail.WinUI.Interfaces;
 using Wino.Mail.WinUI.Models;
 using Wino.Mail.WinUI.Services;
@@ -60,12 +67,19 @@ public partial class App : WinoApplication,
     private bool _hasConfiguredAccounts;
     private bool _isExiting;
     private bool _activationInfrastructureInitialized;
+    private bool _appHostInfrastructureInitialized;
+    private bool _appNotificationsRegistered;
     private int _initialNotificationActivationHandled;
+    private int _initialShareActivationHandled;
     private CancellationTokenSource? _autoSynchronizationLoopCts;
     private readonly SemaphoreSlim _autoSynchronizationSemaphore = new(1, 1);
     private readonly SemaphoreSlim _activationInfrastructureSemaphore = new(1, 1);
+    private readonly SemaphoreSlim _appHostInfrastructureSemaphore = new(1, 1);
     private readonly ConcurrentDictionary<Guid, int> _inboxSyncCounters = [];
+    private readonly AppNotificationActivationBuffer _bufferedAppNotificationActivations = new();
     private NativeTrayIcon? _trayIcon;
+    private readonly record struct NotificationActivationRoute(bool RequiresForegroundWindow, Func<Task>? ExecuteAsync);
+    private readonly record struct ShellWindowActivationResult(IWinoShellWindow? ShellWindow, bool WasCreated);
 
     internal bool IsExiting => _isExiting;
 
@@ -76,6 +90,7 @@ public partial class App : WinoApplication,
         Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
         CryptographyContext.Register(typeof(WindowsSecureMimeContext));
 
+        EnsureAppNotificationRegistration();
         RegisterRecipients();
     }
 
@@ -264,12 +279,16 @@ public partial class App : WinoApplication,
         shellWindow.Close();
     }
 
-    private async Task ActivateWindowAsync(WindowEx window)
+    private async Task ActivateWindowAsync(WindowEx window, bool applyThemeToWindow = true)
     {
         var windowManager = Services.GetRequiredService<IWinoWindowManager>();
         MainWindow = window;
         windowManager.ActivateWindow(window);
-        await NewThemeService.ApplyThemeToActiveWindowAsync();
+
+        if (applyThemeToWindow)
+        {
+            await NewThemeService.ApplyThemeToActiveWindowAsync();
+        }
     }
 
     private Task ExitApplicationAsync()
@@ -351,12 +370,14 @@ public partial class App : WinoApplication,
         services.AddTransient(typeof(AccountDetailsPageViewModel));
         services.AddTransient(typeof(SignatureManagementPageViewModel));
         services.AddTransient(typeof(MessageListPageViewModel));
+        services.AddTransient(typeof(MailNotificationSettingsPageViewModel));
         services.AddTransient(typeof(ReadComposePanePageViewModel));
         services.AddTransient(typeof(MergedAccountDetailsPageViewModel));
         services.AddTransient(typeof(AppPreferencesPageViewModel));
         services.AddTransient(typeof(StoragePageViewModel));
         services.AddTransient(typeof(WinoAccountManagementPageViewModel));
         services.AddTransient(typeof(AliasManagementPageViewModel));
+        services.AddTransient(typeof(MailCategoryManagementPageViewModel));
         services.AddTransient(typeof(ContactsPageViewModel));
         services.AddTransient(typeof(SignatureAndEncryptionPageViewModel));
         services.AddTransient(typeof(EmailTemplatesPageViewModel));
@@ -401,6 +422,12 @@ public partial class App : WinoApplication,
         => Services.GetRequiredService<IWinoWindowManager>().GetWindow(WinoWindowKind.Shell) is IWinoShellWindow;
 
     private async Task EnsureActivationInfrastructureAsync()
+    {
+        await EnsureCoreActivationInfrastructureAsync();
+        await EnsureAppHostInfrastructureAsync();
+    }
+
+    private async Task EnsureCoreActivationInfrastructureAsync()
     {
         if (_activationInfrastructureInitialized)
             return;
@@ -412,7 +439,7 @@ public partial class App : WinoApplication,
             if (_activationInfrastructureInitialized)
                 return;
 
-            TryRegisterAppNotifications();
+            EnsureAppNotificationRegistration();
 
             await Services.GetRequiredService<ReleaseLocalAccountDataCleanupService>()
                 .RunIfNeededAsync();
@@ -423,18 +450,8 @@ public partial class App : WinoApplication,
             _preferencesService = Services.GetRequiredService<IPreferencesService>();
             _accountService = Services.GetRequiredService<IAccountService>();
 
-            EnsureWindowManagerConfigured();
-            EnsureTrayIconCreated();
-
             _hasConfiguredAccounts = (await _accountService.GetAccountsAsync()).Any();
 
-            if (_hasConfiguredAccounts)
-            {
-                _preferencesService.PreferenceChanged -= PreferencesServiceChanged;
-                _preferencesService.PreferenceChanged += PreferencesServiceChanged;
-                RestartAutoSynchronizationLoop();
-            }
-
             _activationInfrastructureInitialized = true;
         }
         finally
@@ -443,111 +460,165 @@ public partial class App : WinoApplication,
         }
     }
 
+    private async Task EnsureAppHostInfrastructureAsync()
+    {
+        await EnsureCoreActivationInfrastructureAsync();
+
+        if (_appHostInfrastructureInitialized)
+            return;
+
+        await _appHostInfrastructureSemaphore.WaitAsync();
+
+        try
+        {
+            if (_appHostInfrastructureInitialized)
+                return;
+
+            EnsureWindowManagerConfigured();
+            EnsureTrayIconCreated();
+
+            if (_hasConfiguredAccounts)
+            {
+                _preferencesService!.PreferenceChanged -= PreferencesServiceChanged;
+                _preferencesService.PreferenceChanged += PreferencesServiceChanged;
+                RestartAutoSynchronizationLoop();
+            }
+
+            _appHostInfrastructureInitialized = true;
+        }
+        finally
+        {
+            _appHostInfrastructureSemaphore.Release();
+        }
+    }
+
     private bool TryMarkInitialNotificationActivationHandled()
         => Interlocked.Exchange(ref _initialNotificationActivationHandled, 1) == 0;
 
+    private bool TryMarkInitialShareActivationHandled()
+        => Interlocked.Exchange(ref _initialShareActivationHandled, 1) == 0;
+
     protected override async void OnLaunched(Microsoft.UI.Xaml.LaunchActivatedEventArgs args)
     {
         base.OnLaunched(args);
 
-        await EnsureActivationInfrastructureAsync();
+        await EnsureCoreActivationInfrastructureAsync();
+
+        var activationArgs = ResolveStartupActivation();
+
+        if (await TryHandleStartupAppNotificationActivationAsync(activationArgs))
+            return;
+
+        await EnsureAppHostInfrastructureAsync();
 
         var hasAnyAccount = _hasConfiguredAccounts;
-        if (!IsStartupTaskLaunch() && !hasAnyAccount)
+        var isStartupTaskLaunch = activationArgs.Kind == ExtendedActivationKind.StartupTask;
+
+        if (!hasAnyAccount && !isStartupTaskLaunch)
         {
-            CreateWelcomeWindow();
-            await NewThemeService.InitializeAsync();
-            MainWindow?.Activate();
-            LogActivation("Welcome window created and activated.");
+            await LaunchWelcomeWindowAsync();
             return;
         }
 
-        // Check if launched from toast notification.
-        if (IsNotificationActivation(out AppNotificationActivatedEventArgs toastArgs) &&
-            TryMarkInitialNotificationActivationHandled())
-        {
-            LogActivation($"Processing notification activation from OnLaunched. Arguments: {toastArgs.Argument}");
-            await HandleToastActivationAsync(toastArgs.Argument, toastArgs.UserInput);
+        if (await TryHandleLaunchActivationAsync(args, activationArgs))
             return;
-        }
 
-        if (ToastActivationResolver.TryParse(args.Arguments, out var launchToastArguments) &&
-            TryMarkInitialNotificationActivationHandled())
-        {
-            LogActivation($"Processing toast launch activation from OnLaunched. Arguments: {args.Arguments}");
-            await HandleToastActivationAsync(launchToastArguments);
-            return;
-        }
-
-        // Check if launched by startup task.
-        bool isStartupTaskLaunch = IsStartupTaskLaunch();
-
-        if (isStartupTaskLaunch && !hasAnyAccount)
-        {
-            CreateWelcomeWindow();
-        }
-        else
-        {
-            CreateWindow(args);
-        }
-
-        // Initialize theme service after window creation.
-        // Theme service requires the window to exist to properly load and apply themes.
-        await NewThemeService.InitializeAsync();
-
-        if (hasAnyAccount)
-        {
-            // Wino account loading and activation.
-            await LoadInitialWinoAccountAsync();
-        }
-
-        LogActivation("Theme service initialized.");
-
-        // If startup task launch, keep window hidden (system tray only).
-        // Otherwise, activate the window normally.
-        if (isStartupTaskLaunch)
-        {
-            LogActivation("Launched by startup task. Window created but hidden (system tray only).");
-        }
-        else
-        {
-            // Normal launch - show and activate the window.
-            // The What's New dialog is shown from MailAppShellViewModel.OnNavigatedTo once XamlRoot is ready.
-            MainWindow?.Activate();
-            LogActivation("Window created and activated.");
-        }
+        await CompleteStandardLaunchAsync(args, hasAnyAccount, isStartupTaskLaunch);
     }
 
-    public async Task HandleInitialActivationAsync()
+    private AppActivationArguments ResolveStartupActivation()
     {
         var activationArgs = AppInstance.GetCurrent().GetActivatedEventArgs();
+        if (Program.TryConsumeDeferredAppNotificationStartup())
+        {
+            LogActivation($"Resolved deferred COM activation after notification registration. Kind: {activationArgs.Kind}");
+        }
 
+        return activationArgs;
+    }
+
+    private async Task<bool> TryHandleStartupAppNotificationActivationAsync(AppActivationArguments activationArgs)
+    {
         if (activationArgs.Kind != ExtendedActivationKind.AppNotification ||
             activationArgs.Data is not AppNotificationActivatedEventArgs toastArgs ||
             !TryMarkInitialNotificationActivationHandled())
         {
-            return;
+            return false;
         }
 
-        LogActivation($"Processing initial notification activation from application startup. Arguments: {toastArgs.Argument}");
+        LogActivation($"Processing app-notification activation from startup. Arguments: {toastArgs.Argument}");
 
-        await EnsureActivationInfrastructureAsync();
-        await HandleToastActivationAsync(toastArgs.Argument, toastArgs.UserInput);
+        if (!TryResolveNotificationActivationRoute(toastArgs, out var route))
+        {
+            await HandleToastActivationAsync(toastArgs.Argument, toastArgs.UserInput);
+
+            if (!IsAppRunning())
+            {
+                LogActivation("Startup app-notification activation completed without a window. Exiting transient process.");
+                ExitApplication();
+            }
+
+            return true;
+        }
+
+        if (route.RequiresForegroundWindow)
+        {
+            await EnsureAppHostInfrastructureAsync();
+            await route.ExecuteAsync!.Invoke();
+            return true;
+        }
+
+        await route.ExecuteAsync!.Invoke();
+
+        if (!IsAppRunning())
+        {
+            LogActivation("Background startup app-notification activation completed. Exiting without creating app host.");
+            ExitApplication();
+        }
+
+        return true;
     }
 
     private void AppNotificationInvoked(AppNotificationManager sender, AppNotificationActivatedEventArgs args)
     {
+        if (!_activationInfrastructureInitialized)
+        {
+            LogActivation($"Buffering app notification activation until infrastructure is ready. Arguments: {args.Argument}");
+            _bufferedAppNotificationActivations.Enqueue(args);
+            return;
+        }
+
         // AppNotification callbacks are not guaranteed to run on the UI thread.
         // Marshal toast handling to the window dispatcher before touching window APIs.
-        if (MainWindow?.DispatcherQueue?.TryEnqueue(() => _ = HandleToastActivationAsync(args.Argument, args.UserInput)) == true)
+        if (TryEnqueueActivationOnUiThread(() => _ = HandleToastActivationAsync(args.Argument, args.UserInput)))
             return;
 
         LogActivation($"Processing notification activation from NotificationInvoked. Arguments: {args.Argument}");
         _ = HandleToastActivationAsync(args.Argument, args.UserInput);
     }
 
-    private void TryRegisterAppNotifications()
+    private bool TryResolveNotificationActivationRoute(AppNotificationActivatedEventArgs notificationArgs,
+                                                       out NotificationActivationRoute route)
     {
+        route = default;
+
+        if (!ToastActivationResolver.TryParse(notificationArgs.Argument, out var toastArguments))
+            return false;
+
+        return TryCreateNotificationActivationRoute(toastArguments, notificationArgs.UserInput, out route);
+    }
+
+    private void EnsureAppNotificationRegistration()
+    {
+        if (!Program.ShouldRegisterAppNotifications())
+        {
+            LogActivation("Skipping app notification registration for non-host entry activation.");
+            return;
+        }
+
+        if (_appNotificationsRegistered)
+            return;
+
         var notificationManager = AppNotificationManager.Default;
 
         notificationManager.NotificationInvoked -= AppNotificationInvoked;
@@ -556,6 +627,7 @@ public partial class App : WinoApplication,
         try
         {
             notificationManager.Register();
+            _appNotificationsRegistered = true;
         }
         catch (Exception ex)
         {
@@ -568,60 +640,17 @@ public partial class App : WinoApplication,
     /// </summary>
     private async Task HandleToastActivationAsync(NotificationArguments toastArguments, IDictionary<string, string>? userInput = null)
     {
-        LogActivation("Handling app notification activation.");
-
-        if (toastArguments.TryGetValue(Constants.ToastStoreUpdateActionKey, out string storeUpdateAction) &&
-            storeUpdateAction == Constants.ToastStoreUpdateActionInstall)
+        if (!TryCreateNotificationActivationRoute(toastArguments, userInput, out var route))
         {
-            await HandleStoreUpdateToastAsync();
+            LogActivation("App notification activation did not match any known handler.");
             return;
         }
 
-        // Check calendar reminder toast activation first.
-        if (toastArguments.TryGetValue(Constants.ToastCalendarActionKey, out string calendarAction) &&
-            toastArguments.TryGetValue(Constants.ToastCalendarItemIdKey, out string calendarItemIdString) &&
-            Guid.TryParse(calendarItemIdString, out Guid calendarItemId))
-        {
-            if (calendarAction == Constants.ToastCalendarNavigateAction)
-            {
-                await HandleCalendarToastNavigationAsync(calendarItemId);
-                return;
-            }
+        LogActivation(route.RequiresForegroundWindow
+            ? "Handling foreground app notification activation."
+            : "Handling background app notification activation.");
 
-            if (calendarAction == Constants.ToastCalendarSnoozeAction)
-            {
-                await HandleCalendarToastSnoozeAsync(userInput, calendarItemId);
-                return;
-            }
-
-            if (calendarAction == Constants.ToastCalendarJoinOnlineAction)
-            {
-                await HandleCalendarToastJoinOnlineAsync(calendarItemId);
-                return;
-            }
-        }
-
-        // Check if this is a navigation toast (user clicked the notification).
-        if (toastArguments.TryGetValue(Constants.ToastActionKey, out MailOperation action) &&
-            Guid.TryParse(toastArguments[Constants.ToastMailUniqueIdKey], out Guid mailItemUniqueId))
-        {
-            if (action == MailOperation.Navigate)
-            {
-                // User clicked notification - create window if needed and navigate.
-                await HandleToastNavigationAsync(mailItemUniqueId);
-            }
-            else
-            {
-                // User clicked action button (Mark as Read, Delete, etc.)
-                // Execute action without window and exit.
-
-                await HandleToastActionAsync(action, mailItemUniqueId);
-            }
-
-            return;
-        }
-
-        LogActivation("App notification activation did not match any known handler.");
+        await route.ExecuteAsync!.Invoke();
     }
 
     private Task HandleToastActivationAsync(string toastArgument, IDictionary<string, string>? userInput = null)
@@ -635,22 +664,150 @@ public partial class App : WinoApplication,
         return HandleToastActivationAsync(toastArguments, userInput);
     }
 
-    private async Task<IWinoShellWindow?> EnsureShellWindowAsync(WinoApplicationMode mode, bool activateWindow, bool suppressStartupFlows = true)
+    private async Task<bool> HandleShareTargetActivationAsync(AppActivationArguments activationArgs, bool activateWindow)
+    {
+        if (activationArgs.Kind != ExtendedActivationKind.ShareTarget ||
+            activationArgs.Data is not ShareTargetActivatedEventArgs shareTargetArgs)
+        {
+            return false;
+        }
+
+        var shareRequest = await ExtractMailShareRequestAsync(shareTargetArgs);
+
+        if (shareRequest?.Files == null || shareRequest.Files.Count == 0)
+        {
+            Services.GetRequiredService<IShareActivationService>().ClearPendingShareRequest();
+            return false;
+        }
+
+        var shareActivationService = Services.GetRequiredService<IShareActivationService>();
+        shareActivationService.PendingShareRequest = shareRequest;
+
+        if (!_hasConfiguredAccounts)
+        {
+            shareActivationService.ClearPendingShareRequest();
+            return false;
+        }
+
+        var shellWindowAlreadyExists = HasShellWindow();
+
+        await EnsureShellWindowAsync(WinoApplicationMode.Mail, activateWindow, suppressStartupFlows: true);
+
+        if (shellWindowAlreadyExists)
+        {
+            await Services.GetRequiredService<MailAppShellViewModel>().HandlePendingShareRequestAsync();
+        }
+
+        return true;
+    }
+
+    private async Task<bool> TryHandleLaunchActivationAsync(Microsoft.UI.Xaml.LaunchActivatedEventArgs args,
+                                                            AppActivationArguments activationArgs)
+    {
+        if (activationArgs.Kind == ExtendedActivationKind.ShareTarget &&
+            TryMarkInitialShareActivationHandled())
+        {
+            LogActivation("Processing share target activation from OnLaunched.");
+
+            if (await HandleShareTargetActivationAsync(activationArgs, activateWindow: true))
+                return true;
+        }
+
+        if (Program.TryConsumePendingBootstrapActivation(out var pendingBootstrapActivation))
+        {
+            LogActivation($"Processing pending bootstrap activation. Kind: {pendingBootstrapActivation.Kind}, Mode: {pendingBootstrapActivation.Mode}");
+
+            if (await HandlePendingBootstrapActivationAsync(pendingBootstrapActivation))
+                return true;
+        }
+
+        if (ToastActivationResolver.TryParse(args.Arguments, out var launchToastArguments) &&
+            TryMarkInitialNotificationActivationHandled())
+        {
+            LogActivation($"Processing toast launch activation from OnLaunched. Arguments: {args.Arguments}");
+            await HandleToastActivationAsync(launchToastArguments);
+            return true;
+        }
+
+        return false;
+    }
+
+    private async Task<MailShareRequest?> ExtractMailShareRequestAsync(ShareTargetActivatedEventArgs shareTargetArgs)
+    {
+        var shareOperation = shareTargetArgs.ShareOperation;
+
+        try
+        {
+            shareOperation.ReportStarted();
+
+            if (!shareOperation.Data.Contains(StandardDataFormats.StorageItems))
+            {
+                shareOperation.ReportCompleted();
+                return null;
+            }
+
+            var storageItems = await shareOperation.Data.GetStorageItemsAsync();
+            List<SharedFile> sharedFiles = [];
+
+            foreach (var storageFile in storageItems.OfType<StorageFile>())
+            {
+                sharedFiles.Add(await storageFile.ToSharedFileAsync());
+            }
+
+            shareOperation.ReportDataRetrieved();
+            shareOperation.ReportCompleted();
+
+            return sharedFiles.Count == 0
+                ? null
+                : new MailShareRequest(sharedFiles);
+        }
+        catch (Exception ex)
+        {
+            LogActivation($"Failed to extract share target payload: {ex.GetType().Name} - {ex.Message}");
+
+            try
+            {
+                shareOperation.ReportError(ex.Message);
+            }
+            catch
+            {
+                // Ignore share reporting failures and fall back to normal launch flow.
+            }
+
+            return null;
+        }
+    }
+
+    private async Task LaunchWelcomeWindowAsync()
+    {
+        CreateWelcomeWindow();
+        await NewThemeService.InitializeAsync();
+        MainWindow?.Activate();
+        LogActivation("Welcome window created and activated.");
+    }
+
+    private async Task<ShellWindowActivationResult> EnsureShellWindowAsync(WinoApplicationMode mode,
+                                                                           bool activateWindow,
+                                                                           bool suppressStartupFlows = true,
+                                                                           object? activationParameter = null)
     {
         var windowManager = Services.GetRequiredService<IWinoWindowManager>();
         var navigationService = Services.GetRequiredService<INavigationService>();
         var shellWindow = windowManager.GetWindow(WinoWindowKind.Shell) as IWinoShellWindow;
+        var wasCreated = false;
 
         if (shellWindow == null)
         {
             LogActivation($"Creating shell window for {mode} activation.");
+            wasCreated = true;
 
             CreateWindow(
                 null,
                 AppEntryConstants.GetModeLaunchArgument(mode),
                 new ShellModeActivationContext
                 {
-                    SuppressStartupFlows = suppressStartupFlows
+                    SuppressStartupFlows = suppressStartupFlows,
+                    Parameter = activationParameter
                 });
 
             await NewThemeService.InitializeAsync();
@@ -664,18 +821,22 @@ public partial class App : WinoApplication,
         }
         else
         {
+            ApplyShellWindowTaskbarIdentity(shellWindow, mode);
             navigationService.ChangeApplicationMode(mode, new ShellModeActivationContext
             {
-                SuppressStartupFlows = suppressStartupFlows
+                SuppressStartupFlows = suppressStartupFlows,
+                Parameter = activationParameter
             });
         }
 
+        ApplyShellWindowTaskbarIdentity(shellWindow, mode);
+
         if (activateWindow && shellWindow is WindowEx window)
         {
-            await ActivateWindowAsync(window);
+            await ActivateWindowAsync(window, applyThemeToWindow: wasCreated);
         }
 
-        return shellWindow;
+        return new ShellWindowActivationResult(shellWindow, wasCreated);
     }
 
     private async Task HandleStoreUpdateToastAsync()
@@ -692,18 +853,42 @@ public partial class App : WinoApplication,
     private async Task HandleCalendarToastNavigationAsync(Guid calendarItemId)
     {
         var calendarService = Services.GetRequiredService<ICalendarService>();
-        var navigationService = Services.GetRequiredService<INavigationService>();
+        var fallbackNavigationArgs = new CalendarPageNavigationArgs
+        {
+            RequestDefaultNavigation = true
+        };
+
+        if (!HasShellWindow())
+        {
+            await EnsureShellWindowAsync(
+                WinoApplicationMode.Calendar,
+                activateWindow: true,
+                activationParameter: fallbackNavigationArgs);
+        }
 
         var calendarItem = await calendarService.GetCalendarItemAsync(calendarItemId);
         if (calendarItem == null)
+        {
+            LogActivation($"Calendar notification navigation item was not found for {calendarItemId}. Opening calendar shell only.");
+
+            await EnsureShellWindowAsync(
+                WinoApplicationMode.Calendar,
+                activateWindow: true,
+                activationParameter: fallbackNavigationArgs);
             return;
+        }
 
         var target = new CalendarItemTarget(calendarItem, CalendarEventTargetType.Single);
+        var navigationArgs = new CalendarPageNavigationArgs
+        {
+            NavigationDate = calendarItem.LocalStartDate,
+            PendingTarget = target
+        };
 
-        await EnsureShellWindowAsync(WinoApplicationMode.Calendar, activateWindow: true);
-
-        navigationService.ChangeApplicationMode(Core.Domain.Enums.WinoApplicationMode.Calendar);
-        navigationService.Navigate(WinoPage.EventDetailsPage, target);
+        await EnsureShellWindowAsync(
+            WinoApplicationMode.Calendar,
+            activateWindow: true,
+            activationParameter: navigationArgs);
     }
 
     private async Task HandleCalendarToastSnoozeAsync(IDictionary<string, string>? userInput, Guid calendarItemId)
@@ -732,6 +917,38 @@ public partial class App : WinoApplication,
         await nativeAppService.LaunchUriAsync(joinUri);
     }
 
+    private async Task CompleteStandardLaunchAsync(Microsoft.UI.Xaml.LaunchActivatedEventArgs args,
+                                                   bool hasAnyAccount,
+                                                   bool isStartupTaskLaunch)
+    {
+        if (isStartupTaskLaunch && !hasAnyAccount)
+        {
+            CreateWelcomeWindow();
+        }
+        else
+        {
+            CreateWindow(args);
+        }
+
+        await NewThemeService.InitializeAsync();
+
+        if (hasAnyAccount)
+        {
+            await LoadInitialWinoAccountAsync();
+        }
+
+        LogActivation("Theme service initialized.");
+
+        if (isStartupTaskLaunch)
+        {
+            LogActivation("Launched by startup task. Window created but hidden (system tray only).");
+            return;
+        }
+
+        MainWindow?.Activate();
+        LogActivation("Window created and activated.");
+    }
+
     private bool TryGetSnoozeDurationMinutes(IDictionary<string, string>? userInput, out int snoozeDurationMinutes)
     {
         snoozeDurationMinutes = _preferencesService?.DefaultSnoozeDurationInMinutes ?? 0;
@@ -755,7 +972,6 @@ public partial class App : WinoApplication,
     private async Task HandleToastNavigationAsync(Guid mailItemUniqueId)
     {
         var mailService = Services.GetRequiredService<IMailService>();
-        var navigationService = Services.GetRequiredService<INavigationService>();
 
         var account = await mailService.GetMailAccountByUniqueIdAsync(mailItemUniqueId);
         if (account == null)
@@ -780,7 +996,6 @@ public partial class App : WinoApplication,
         var shellWindowAlreadyExists = HasShellWindow();
 
         await EnsureShellWindowAsync(WinoApplicationMode.Mail, activateWindow: true);
-        navigationService.ChangeApplicationMode(Core.Domain.Enums.WinoApplicationMode.Mail);
 
         if (shellWindowAlreadyExists)
         {
@@ -880,6 +1095,86 @@ public partial class App : WinoApplication,
         }
     }
 
+    private async Task HandleToastComposeActionAsync(MailOperation action, Guid mailItemUniqueId)
+    {
+        LogActivation($"Handling compose toast action: {action} for mail {mailItemUniqueId}");
+
+        var mailService = Services.GetRequiredService<IMailService>();
+        var folderService = Services.GetRequiredService<IFolderService>();
+        var mimeFileService = Services.GetRequiredService<IMimeFileService>();
+        var navigationService = Services.GetRequiredService<INavigationService>();
+        var requestDelegator = Services.GetRequiredService<IWinoRequestDelegator>();
+        var mailShellViewModel = Services.GetRequiredService<MailAppShellViewModel>();
+
+        var mailItem = await mailService.GetSingleMailItemAsync(mailItemUniqueId);
+        if (mailItem == null)
+        {
+            LogActivation($"Compose toast mail item was not found for {mailItemUniqueId}.");
+            return;
+        }
+
+        var account = await mailService.GetMailAccountByUniqueIdAsync(mailItemUniqueId) ?? mailItem.AssignedAccount;
+        if (account == null)
+        {
+            LogActivation($"Compose toast account was not found for {mailItemUniqueId}.");
+            return;
+        }
+
+        var draftFolder = await folderService.GetSpecialFolderByAccountIdAsync(account.Id, SpecialFolderType.Draft);
+        if (draftFolder == null)
+        {
+            LogActivation($"Compose toast draft folder is missing for account {account.Id}.");
+            return;
+        }
+
+        var mimeInformation = await mimeFileService.GetMimeMessageInformationAsync(mailItem.FileId, account.Id);
+        if (mimeInformation?.MimeMessage == null)
+        {
+            LogActivation($"Compose toast MIME payload was not found for mail {mailItemUniqueId}.");
+            return;
+        }
+
+        await EnsureShellWindowAsync(WinoApplicationMode.Mail, activateWindow: true);
+
+        if (mailShellViewModel.MenuItems.TryGetAccountMenuItem(account.Id, out IAccountMenuItem accountMenuItem))
+        {
+            await mailShellViewModel.ChangeLoadedAccountAsync(accountMenuItem, navigateInbox: false);
+        }
+
+        if (mailShellViewModel.MenuItems.TryGetSpecialFolderMenuItem(account.Id, SpecialFolderType.Draft, out var draftFolderMenuItem))
+        {
+            await mailShellViewModel.NavigateFolderAsync(draftFolderMenuItem);
+        }
+
+        var draftOptions = new DraftCreationOptions
+        {
+            Reason = action switch
+            {
+                MailOperation.Reply => DraftCreationReason.Reply,
+                MailOperation.ReplyAll => DraftCreationReason.ReplyAll,
+                MailOperation.Forward => DraftCreationReason.Forward,
+                _ => DraftCreationReason.Empty
+            },
+            ReferencedMessage = new ReferencedMessage
+            {
+                MimeMessage = mimeInformation.MimeMessage,
+                MailCopy = mailItem
+            }
+        };
+
+        var (draftMailCopy, draftBase64MimeMessage) = await mailService.CreateDraftAsync(account.Id, draftOptions);
+        var draftPreparationRequest = new DraftPreparationRequest(account, draftMailCopy, draftBase64MimeMessage, draftOptions.Reason, mailItem);
+
+        await requestDelegator.ExecuteAsync(draftPreparationRequest);
+        navigationService.Navigate(WinoPage.ComposePage,
+                                   new MailItemViewModel(draftMailCopy),
+                                   NavigationReferenceFrame.RenderingFrame,
+                                   NavigationTransitionType.DrillIn);
+    }
+
+    private static bool IsComposeToastAction(MailOperation action)
+        => action is MailOperation.Reply or MailOperation.ReplyAll or MailOperation.Forward;
+
     /// <summary>
     /// Creates the main window and activates it.
     /// </summary>
@@ -934,6 +1229,7 @@ public partial class App : WinoApplication,
                     ? resolvedActivationMode
                     : AppModeActivationResolver.Resolve(args?.Arguments, GetCurrentLaunchTileId(), Environment.CommandLine, defaultMode);
 
+            ApplyShellWindowTaskbarIdentity(shellWindow, targetMode);
             navigationService.ChangeApplicationMode(targetMode, activationContextOverride);
             return;
         }
@@ -967,6 +1263,18 @@ public partial class App : WinoApplication,
         shellWindow.HandleAppActivation(args?.Arguments, GetCurrentLaunchTileId(), Environment.CommandLine);
     }
 
+    private static void ApplyShellWindowTaskbarIdentity(IWinoShellWindow? shellWindow, WinoApplicationMode mode)
+    {
+        if (shellWindow is not WindowEx window)
+            return;
+
+        var packagedApplicationId = AppEntryConstants.GetPackagedApplicationId(mode);
+        if (packagedApplicationId == null)
+            return;
+
+        WindowAppUserModelIdHelper.TrySet(window, AppEntryConstants.GetAppUserModelId(mode));
+    }
+
     private void CreateWelcomeWindow()
     {
         LogActivation("Creating welcome window.");
@@ -1217,6 +1525,7 @@ public partial class App : WinoApplication,
         return synchronizationType switch
         {
             MailSynchronizationType.Alias => Translator.Exception_FailedToSynchronizeAliases,
+            MailSynchronizationType.Categories => Translator.Exception_FailedToSynchronizeCategories,
             MailSynchronizationType.UpdateProfile => Translator.Exception_FailedToSynchronizeProfileInformation,
             _ => Translator.Exception_FailedToSynchronizeFolders
         };
@@ -1444,7 +1753,12 @@ public partial class App : WinoApplication,
                 // Handle toast notification activation
                 var toastArgs = (AppNotificationActivatedEventArgs)args.Data;
                 LogActivation($"Processing redirected notification activation. Arguments: {toastArgs.Argument}");
-                _ = HandleToastActivationAsync(toastArgs.Argument, toastArgs.UserInput);
+                await HandleToastActivationAsync(toastArgs.Argument, toastArgs.UserInput);
+            }
+            else if (args.Kind == ExtendedActivationKind.ShareTarget)
+            {
+                LogActivation("Processing redirected share target activation.");
+                await HandleShareTargetActivationAsync(args, activateWindow: true);
             }
             else
             {
@@ -1459,7 +1773,7 @@ public partial class App : WinoApplication,
                         {
                             shouldActivateWindow = ToastActivationResolver.ShouldBringToForeground(launchToastArguments);
                             LogActivation($"Processing redirected toast launch activation. Arguments: {launchArgs.Arguments}");
-                            _ = HandleToastActivationAsync(launchToastArguments);
+                            await HandleToastActivationAsync(launchToastArguments);
                         }
                         else
                         {
@@ -1489,12 +1803,89 @@ public partial class App : WinoApplication,
         }
 
         // Dispatch to UI thread since this is called from Program.OnActivated.
-        if (MainWindow?.DispatcherQueue.TryEnqueue(() => _ = HandleRedirectedActivationAsync()) == true)
+        if (TryEnqueueActivationOnUiThread(() => _ = HandleRedirectedActivationAsync()))
             return;
 
         _ = HandleRedirectedActivationAsync();
     }
 
+    private bool TryCreateNotificationActivationRoute(NotificationArguments toastArguments,
+                                                      IDictionary<string, string>? userInput,
+                                                      out NotificationActivationRoute route)
+    {
+        if (toastArguments.TryGetValue(Constants.ToastStoreUpdateActionKey, out string storeUpdateAction) &&
+            storeUpdateAction == Constants.ToastStoreUpdateActionInstall)
+        {
+            route = new NotificationActivationRoute(true, HandleStoreUpdateToastAsync);
+            return true;
+        }
+
+        if (toastArguments.TryGetValue(Constants.ToastDismissActionKey, out string _))
+        {
+            route = new NotificationActivationRoute(false, () =>
+            {
+                LogActivation("Handling notification dismiss action.");
+                return Task.CompletedTask;
+            });
+            return true;
+        }
+
+        if (toastArguments.TryGetValue(Constants.ToastCalendarActionKey, out string calendarAction) &&
+            toastArguments.TryGetValue(Constants.ToastCalendarItemIdKey, out string calendarItemIdString) &&
+            Guid.TryParse(calendarItemIdString, out Guid calendarItemId))
+        {
+            route = calendarAction switch
+            {
+                Constants.ToastCalendarNavigateAction => new NotificationActivationRoute(true, () => HandleCalendarToastNavigationAsync(calendarItemId)),
+                Constants.ToastCalendarSnoozeAction => new NotificationActivationRoute(false, () => HandleCalendarToastSnoozeAsync(userInput, calendarItemId)),
+                Constants.ToastCalendarJoinOnlineAction => new NotificationActivationRoute(false, () => HandleCalendarToastJoinOnlineAsync(calendarItemId)),
+                _ => default
+            };
+
+            return route.ExecuteAsync != null;
+        }
+
+        if (toastArguments.TryGetValue(Constants.ToastActionKey, out MailOperation action) &&
+            Guid.TryParse(toastArguments[Constants.ToastMailUniqueIdKey], out Guid mailItemUniqueId))
+        {
+            if (action == MailOperation.Navigate)
+            {
+                route = new NotificationActivationRoute(true, () => HandleToastNavigationAsync(mailItemUniqueId));
+                return true;
+            }
+
+            if (IsComposeToastAction(action))
+            {
+                route = new NotificationActivationRoute(true, () => HandleToastComposeActionAsync(action, mailItemUniqueId));
+                return true;
+            }
+
+            route = new NotificationActivationRoute(false, () => HandleToastActionAsync(action, mailItemUniqueId));
+            return true;
+        }
+
+        route = default;
+        return false;
+    }
+
+    private async Task<bool> HandlePendingBootstrapActivationAsync(PendingBootstrapActivation pendingBootstrapActivation)
+    {
+        if (pendingBootstrapActivation.Mode != WinoApplicationMode.Calendar)
+            return false;
+
+        var navigationArgs = new CalendarPageNavigationArgs
+        {
+            RequestDefaultNavigation = true
+        };
+
+        await EnsureShellWindowAsync(
+            WinoApplicationMode.Calendar,
+            activateWindow: true,
+            activationParameter: navigationArgs);
+
+        return true;
+    }
+
     private static string AppendLaunchArgument(string? launchArguments, string launchArgument)
     {
         return string.IsNullOrWhiteSpace(launchArguments)
@@ -1527,6 +1918,12 @@ public partial class App : WinoApplication,
 
         }
 
+        if (activationArgs.Kind == ExtendedActivationKind.ShareTarget)
+        {
+            mode = WinoApplicationMode.Mail;
+            return true;
+        }
+
         if (activationArgs.Kind == ExtendedActivationKind.File &&
             activationArgs.Data is IFileActivatedEventArgs fileArgs)
         {
@@ -1569,6 +1966,32 @@ public partial class App : WinoApplication,
         return null;
     }
 
+    private bool TryEnqueueActivationOnUiThread(Action action)
+    {
+        var dispatcherQueue = MainWindow?.DispatcherQueue;
+
+        if (dispatcherQueue == null)
+        {
+            var windowManager = Services.GetService<IWinoWindowManager>();
+            var currentWindow = windowManager?.ActiveWindow
+                               ?? windowManager?.GetWindow(WinoWindowKind.Shell)
+                               ?? windowManager?.GetWindow(WinoWindowKind.Welcome);
+
+            dispatcherQueue = currentWindow?.DispatcherQueue;
+        }
+
+        if (dispatcherQueue == null)
+            return false;
+
+        if (dispatcherQueue.HasThreadAccess)
+        {
+            action();
+            return true;
+        }
+
+        return dispatcherQueue.TryEnqueue(() => action());
+    }
+
 }