diff --git a/Wino.Core.Domain/Enums/MailUpdateSource.cs b/Wino.Core.Domain/Enums/MailUpdateSource.cs
new file mode 100644
index 00000000..4e5b86bf
--- /dev/null
+++ b/Wino.Core.Domain/Enums/MailUpdateSource.cs
@@ -0,0 +1,17 @@
+namespace Wino.Core.Domain.Enums;
+
+/// <summary>
+/// Indicates the source of a mail update.
+/// </summary>
+public enum MailUpdateSource
+{
+    /// <summary>
+    /// Update originated from client-side UI changes (ApplyUIChanges/RevertUIChanges).
+    /// </summary>
+    Client,
+
+    /// <summary>
+    /// Update originated from server synchronization or database operations.
+    /// </summary>
+    Server
+}
diff --git a/Wino.Core/Requests/Folder/MarkFolderAsReadRequest.cs b/Wino.Core/Requests/Folder/MarkFolderAsReadRequest.cs
index 74ffa5eb..1c0e4f4b 100644
--- a/Wino.Core/Requests/Folder/MarkFolderAsReadRequest.cs
+++ b/Wino.Core/Requests/Folder/MarkFolderAsReadRequest.cs
@@ -17,7 +17,7 @@ public record MarkFolderAsReadRequest(MailItemFolder Folder, List<MailCopy> Mail
         {
             item.IsRead = true;
 
-            WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(item));
+            WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(item, MailUpdateSource.Client));
         }
     }
 
@@ -27,7 +27,7 @@ public record MarkFolderAsReadRequest(MailItemFolder Folder, List<MailCopy> Mail
         {
             item.IsRead = false;
 
-            WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(item));
+            WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(item, MailUpdateSource.Client));
         }
     }
 
diff --git a/Wino.Core/Requests/Mail/ChangeFlagRequest.cs b/Wino.Core/Requests/Mail/ChangeFlagRequest.cs
index 8410cd8e..4ae4800c 100644
--- a/Wino.Core/Requests/Mail/ChangeFlagRequest.cs
+++ b/Wino.Core/Requests/Mail/ChangeFlagRequest.cs
@@ -22,14 +22,14 @@ public record ChangeFlagRequest(MailCopy Item, bool IsFlagged) : MailRequestBase
     {
         Item.IsFlagged = IsFlagged;
 
-        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item));
+        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item, MailUpdateSource.Client));
     }
 
     public override void RevertUIChanges()
     {
         Item.IsFlagged = !IsFlagged;
 
-        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item));
+        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item, MailUpdateSource.Client));
     }
 }
 
diff --git a/Wino.Core/Requests/Mail/MarkReadRequest.cs b/Wino.Core/Requests/Mail/MarkReadRequest.cs
index fded7f8b..046aee01 100644
--- a/Wino.Core/Requests/Mail/MarkReadRequest.cs
+++ b/Wino.Core/Requests/Mail/MarkReadRequest.cs
@@ -21,14 +21,14 @@ public record MarkReadRequest(MailCopy Item, bool IsRead) : MailRequestBase(Item
     {
         Item.IsRead = IsRead;
 
-        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item));
+        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item, MailUpdateSource.Client));
     }
 
     public override void RevertUIChanges()
     {
         Item.IsRead = !IsRead;
 
-        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item));
+        WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item, MailUpdateSource.Client));
     }
 }
 
diff --git a/Wino.Mail.ViewModels/ComposePageViewModel.cs b/Wino.Mail.ViewModels/ComposePageViewModel.cs
index bb790860..f558f308 100644
--- a/Wino.Mail.ViewModels/ComposePageViewModel.cs
+++ b/Wino.Mail.ViewModels/ComposePageViewModel.cs
@@ -633,9 +633,9 @@ public partial class ComposePageViewModel : MailBaseViewModel
         _dialogService.InfoBarMessage(Translator.Info_InvalidAddressTitle, string.Format(Translator.Info_InvalidAddressMessage, address), InfoBarMessageType.Warning);
     }
 
-    protected override async void OnMailUpdated(MailCopy updatedMail)
+    protected override async void OnMailUpdated(MailCopy updatedMail, MailUpdateSource source)
     {
-        base.OnMailUpdated(updatedMail);
+        base.OnMailUpdated(updatedMail, source);
 
         if (CurrentMailDraftItem == null) return;
 
diff --git a/Wino.Mail.ViewModels/MailBaseViewModel.cs b/Wino.Mail.ViewModels/MailBaseViewModel.cs
index e27324ce..53646754 100644
--- a/Wino.Mail.ViewModels/MailBaseViewModel.cs
+++ b/Wino.Mail.ViewModels/MailBaseViewModel.cs
@@ -1,6 +1,7 @@
 using CommunityToolkit.Mvvm.Messaging;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Entities.Shared;
+using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Models.Folders;
 using Wino.Core.ViewModels;
 using Wino.Messaging.UI;
@@ -20,7 +21,7 @@ public class MailBaseViewModel : CoreBaseViewModel,
 {
     protected virtual void OnMailAdded(MailCopy addedMail) { }
     protected virtual void OnMailRemoved(MailCopy removedMail) { }
-    protected virtual void OnMailUpdated(MailCopy updatedMail) { }
+    protected virtual void OnMailUpdated(MailCopy updatedMail, MailUpdateSource source) { }
     protected virtual void OnMailDownloaded(MailCopy downloadedMail) { }
     protected virtual void OnDraftCreated(MailCopy draftMail, MailAccount account) { }
     protected virtual void OnDraftFailed(MailCopy draftMail, MailAccount account) { }
@@ -30,7 +31,7 @@ public class MailBaseViewModel : CoreBaseViewModel,
 
     void IRecipient<MailAddedMessage>.Receive(MailAddedMessage message) => OnMailAdded(message.AddedMail);
     void IRecipient<MailRemovedMessage>.Receive(MailRemovedMessage message) => OnMailRemoved(message.RemovedMail);
-    void IRecipient<MailUpdatedMessage>.Receive(MailUpdatedMessage message) => OnMailUpdated(message.UpdatedMail);
+    void IRecipient<MailUpdatedMessage>.Receive(MailUpdatedMessage message) => OnMailUpdated(message.UpdatedMail, message.Source);
     void IRecipient<MailDownloadedMessage>.Receive(MailDownloadedMessage message) => OnMailDownloaded(message.DownloadedMail);
 
     void IRecipient<DraftMapped>.Receive(DraftMapped message) => OnDraftMapped(message.LocalDraftCopyId, message.RemoteDraftCopyId);
diff --git a/Wino.Mail.ViewModels/MailListPageViewModel.cs b/Wino.Mail.ViewModels/MailListPageViewModel.cs
index c8905d51..27139c2f 100644
--- a/Wino.Mail.ViewModels/MailListPageViewModel.cs
+++ b/Wino.Mail.ViewModels/MailListPageViewModel.cs
@@ -664,9 +664,9 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
     }
 
-    protected override async void OnMailUpdated(MailCopy updatedMail)
+    protected override async void OnMailUpdated(MailCopy updatedMail, MailUpdateSource source)
     {
-        base.OnMailUpdated(updatedMail);
+        base.OnMailUpdated(updatedMail, source);
 
         await MailCollection.UpdateMailCopy(updatedMail);
 
diff --git a/Wino.Mail.ViewModels/MailRenderingPageViewModel.cs b/Wino.Mail.ViewModels/MailRenderingPageViewModel.cs
index bc14d954..5c6a51b2 100644
--- a/Wino.Mail.ViewModels/MailRenderingPageViewModel.cs
+++ b/Wino.Mail.ViewModels/MailRenderingPageViewModel.cs
@@ -618,9 +618,9 @@ public partial class MailRenderingPageViewModel : MailBaseViewModel,
             MenuItems.Add(MailOperationMenuItem.Create(MailOperation.MarkAsRead, true, false));
     }
 
-    protected override async void OnMailUpdated(MailCopy updatedMail)
+    protected override async void OnMailUpdated(MailCopy updatedMail, MailUpdateSource source)
     {
-        base.OnMailUpdated(updatedMail);
+        base.OnMailUpdated(updatedMail, source);
 
         if (initializedMailItemViewModel == null) return;
 
diff --git a/Wino.Messages/UI/MailUpdatedMessage.cs b/Wino.Messages/UI/MailUpdatedMessage.cs
index b0c140e2..546a8d9d 100644
--- a/Wino.Messages/UI/MailUpdatedMessage.cs
+++ b/Wino.Messages/UI/MailUpdatedMessage.cs
@@ -1,5 +1,6 @@
 using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
 
 namespace Wino.Messaging.UI;
 
-public record MailUpdatedMessage(MailCopy UpdatedMail) : UIMessageBase<MailUpdatedMessage>;
+public record MailUpdatedMessage(MailCopy UpdatedMail, MailUpdateSource Source) : UIMessageBase<MailUpdatedMessage>;
diff --git a/Wino.Services/MailService.cs b/Wino.Services/MailService.cs
index 6a1e3008..e338f680 100644
--- a/Wino.Services/MailService.cs
+++ b/Wino.Services/MailService.cs
@@ -543,7 +543,7 @@ public class MailService : BaseDatabaseService, IMailService
 
         await Connection.UpdateAsync(mailCopy, typeof(MailCopy)).ConfigureAwait(false);
 
-        ReportUIChange(new MailUpdatedMessage(mailCopy));
+        ReportUIChange(new MailUpdatedMessage(mailCopy, MailUpdateSource.Server));
     }
 
     private async Task DeleteMailInternalAsync(MailCopy mailCopy, bool preserveMimeFile)