diff --git a/src/OutlookAddin.UI/ViewModels/SettingsViewModel.cs b/src/OutlookAddin.UI/ViewModels/SettingsViewModel.cs
index 031edd4..7ac8530 100644
--- a/src/OutlookAddin.UI/ViewModels/SettingsViewModel.cs
+++ b/src/OutlookAddin.UI/ViewModels/SettingsViewModel.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Linq;
 using System.Net.Http;
 using System.Threading.Tasks;
 using System.Windows.Media;
@@ -178,18 +179,61 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
                 }
 
                 var deployment = System.Deployment.Application.ApplicationDeployment.CurrentDeployment;
-                var info = await Task.Run(() => deployment.CheckForDetailedUpdate(false)).ConfigureAwait(true);
-                if (!info.UpdateAvailable)
+                var currentVersion = deployment.CurrentVersion;
+                var manifestUri = deployment.UpdateLocation;
+
+                // ApplicationDeployment.CheckForDetailedUpdate triggers a
+                // TrustManager re-evaluation which throws TrustNotGranted
+                // inside a hosted VSTO process even when the publisher and
+                // permissions are unchanged. Bypass it by fetching the
+                // deployment manifest directly and reading the version.
+                Version? availableVersion = null;
+                try
                 {
-                    UpdateStatusBrush = SuccessBrush;
-                    UpdateStatus = "אתה על הגרסה האחרונה (" + deployment.CurrentVersion + ").";
+                    availableVersion = await Task.Run(() => FetchManifestVersion(manifestUri)).ConfigureAwait(true);
+                }
+                catch (Exception fetchEx)
+                {
+                    _logger.Warning(fetchEx, "CheckForUpdate: manifest fetch failed");
+                    UpdateStatusBrush = ErrorBrush;
+                    UpdateStatus = "שגיאה בבדיקת השרת: " + fetchEx.Message;
                     return;
                 }
 
-                UpdateStatus = $"זמינה גרסה {info.AvailableVersion} — מוריד…";
-                var result = await Task.Run(() => deployment.Update()).ConfigureAwait(true);
-                UpdateStatusBrush = SuccessBrush;
-                UpdateStatus = $"הותקנה גרסה {info.AvailableVersion}. סגור ופתח את Outlook כדי לטעון אותה.";
+                if (availableVersion == null)
+                {
+                    UpdateStatusBrush = ErrorBrush;
+                    UpdateStatus = "לא ניתן לקרוא את גרסת השרת מ-" + manifestUri;
+                    return;
+                }
+
+                if (availableVersion <= currentVersion)
+                {
+                    UpdateStatusBrush = SuccessBrush;
+                    UpdateStatus = "אתה על הגרסה האחרונה (" + currentVersion + ").";
+                    return;
+                }
+
+                // VSTO add-ins cannot be updated programmatically from inside
+                // a running Outlook — ApplicationDeployment.Update() throws.
+                // Open the .vsto URL via the shell; Windows hands it to
+                // VSTOInstaller.exe which installs the update correctly.
+                try
+                {
+                    System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo(manifestUri.ToString())
+                    {
+                        UseShellExecute = true
+                    });
+                    UpdateStatusBrush = SuccessBrush;
+                    UpdateStatus = $"זמינה גרסה {availableVersion} — אשר את ההתקנה בחלון שנפתח, ואז סגור ופתח את Outlook.";
+                }
+                catch (Exception launchEx)
+                {
+                    _logger.Warning(launchEx, "CheckForUpdate: shell launch of installer URL failed");
+                    UpdateStatusBrush = ErrorBrush;
+                    UpdateStatus = $"זמינה גרסה {availableVersion} אבל לא הצלחנו לפתוח את חלון ההתקנה. גש ידנית ל-{manifestUri}";
+                }
+                return;
             }
             catch (System.Deployment.Application.DeploymentDownloadException ex)
             {
@@ -215,6 +259,33 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
             }
         }
 
+        /// <summary>
+        /// Reads the top-level &lt;assemblyIdentity&gt; version from the
+        /// .vsto deployment manifest at <paramref name="manifestUri"/>.
+        /// Returns null if the document doesn't look like a deployment
+        /// manifest. Runs on a worker thread (synchronous HTTP).
+        /// </summary>
+        private static Version? FetchManifestVersion(Uri manifestUri)
+        {
+            // The .vsto manifest is small (≈6KB). Keep this synchronous —
+            // no point pulling in HttpClient and its lifecycle just for one
+            // GET. WebRequest works fine on .NET FW 4.8 and through proxies.
+            var req = System.Net.WebRequest.Create(manifestUri);
+            req.Timeout = 10_000;
+            using (var response = req.GetResponse())
+            using (var stream = response.GetResponseStream())
+            {
+                var doc = System.Xml.Linq.XDocument.Load(stream);
+                System.Xml.Linq.XNamespace asmv1 = "urn:schemas-microsoft-com:asm.v1";
+                var identity = doc.Root?
+                    .Elements()
+                    .FirstOrDefault(e => e.Name.LocalName == "assemblyIdentity" && e.Name.Namespace == asmv1);
+                var versionAttr = identity?.Attribute("version")?.Value;
+                if (string.IsNullOrWhiteSpace(versionAttr)) return null;
+                return Version.TryParse(versionAttr, out var v) ? v : null;
+            }
+        }
+
         private bool CanCheckForUpdate() => !IsCheckingForUpdate;
 
         partial void OnIsCheckingForUpdateChanged(bool value)
diff --git a/src/OutlookAddin/OutlookAddin.csproj b/src/OutlookAddin/OutlookAddin.csproj
index d02b71d..f988aad 100644
--- a/src/OutlookAddin/OutlookAddin.csproj
+++ b/src/OutlookAddin/OutlookAddin.csproj
@@ -36,7 +36,7 @@
     <PublishUrl>C:\Users\Chaim\source\repos\OutlookAddin\Publish\</PublishUrl>
     <InstallUrl>https://gitea.dev.marcus-law.co.il/espocrm-extensions/OutlookAddin/raw/branch/main/Publish/</InstallUrl>
     <TargetCulture>en</TargetCulture>
-    <ApplicationVersion>1.2.2.0</ApplicationVersion>
+    <ApplicationVersion>1.2.3.0</ApplicationVersion>
     <AutoIncrementApplicationRevision>false</AutoIncrementApplicationRevision>
     <UpdateEnabled>true</UpdateEnabled>
     <UpdateInterval>7</UpdateInterval>
diff --git a/src/OutlookAddin/Properties/AssemblyInfo.cs b/src/OutlookAddin/Properties/AssemblyInfo.cs
index 3db4c4b..2ae3427 100644
--- a/src/OutlookAddin/Properties/AssemblyInfo.cs
+++ b/src/OutlookAddin/Properties/AssemblyInfo.cs
@@ -33,6 +33,6 @@ using System.Security;
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.2.2.0")]
-[assembly: AssemblyFileVersion("1.2.2.0")]
+[assembly: AssemblyVersion("1.2.3.0")]
+[assembly: AssemblyFileVersion("1.2.3.0")]