diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/DeviceTokenServiceTests.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/DeviceTokenServiceTests.cs
index ec1a435d..15ba5786 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/DeviceTokenServiceTests.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/DeviceTokenServiceTests.cs
@@ -63,6 +63,42 @@ public async Task RegisterAsync_SameTokenTwice_UpsertsWithoutDuplicate()
         Assert.That(stored.Platform, Is.EqualTo("ios"));
     }
 
+    [Test]
+    public async Task RegisterAsync_NewToken_PersistsAppBuildNumber()
+    {
+        var result = await _service.RegisterAsync(42, "build-token", "android", 31221);
+
+        Assert.That(result.Success, Is.True);
+
+        var stored = await TimePlanningPnDbContext!.DeviceTokens.SingleAsync();
+        Assert.That(stored.AppBuildNumber, Is.EqualTo(31221));
+    }
+
+    [Test]
+    public async Task RegisterAsync_ReRegister_UpdatesAppBuildNumber()
+    {
+        await _service.RegisterAsync(42, "build-token", "android", 31221);
+
+        var result = await _service.RegisterAsync(42, "build-token", "android", 40000);
+
+        Assert.That(result.Success, Is.True);
+        Assert.That(await TimePlanningPnDbContext!.DeviceTokens.CountAsync(), Is.EqualTo(1));
+
+        var stored = await TimePlanningPnDbContext.DeviceTokens.SingleAsync();
+        Assert.That(stored.AppBuildNumber, Is.EqualTo(40000),
+            "a re-register must refresh the stored app build number");
+    }
+
+    [Test]
+    public async Task RegisterAsync_DefaultBuildNumber_PersistsZero()
+    {
+        await _service.RegisterAsync(42, "legacy-token", "android");
+
+        var stored = await TimePlanningPnDbContext!.DeviceTokens.SingleAsync();
+        Assert.That(stored.AppBuildNumber, Is.EqualTo(0),
+            "an old client that omits the build number is stored as 0");
+    }
+
     [Test]
     public async Task UnregisterAsync_ExistingToken_IsRemoved()
     {
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/PushNotificationServiceTests.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/PushNotificationServiceTests.cs
index 47fca3b1..2499e494 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/PushNotificationServiceTests.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/PushNotificationServiceTests.cs
@@ -1,5 +1,9 @@
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
+using FirebaseAdmin.Messaging;
 using Microsoft.Extensions.Logging;
+using Microting.TimePlanningBase.Infrastructure.Data.Entities;
 using NSubstitute;
 using NUnit.Framework;
 using TimePlanning.Pn.Services.PushNotificationService;
@@ -29,10 +33,87 @@ public void Constructor_WithoutFirebaseConfig_DoesNotThrow()
     [Test]
     public async Task SendToSiteAsync_WhenFirebaseNotConfigured_IsNoOp()
     {
-        var service = new PushNotificationService(
-            TimePlanningPnDbContext!,
-            Substitute.For<ILogger<PushNotificationService>>());
+        var service = CreateService();
 
         await service.SendToSiteAsync(1, "Title", "Body");
     }
+
+    [Test]
+    public void BuildMessage_DataOnly_OmitsNotificationAndSetsContentAvailable()
+    {
+        var msg = PushNotificationService.BuildMessage(
+            "tok",
+            "",
+            "",
+            new Dictionary<string, string> { { "type", "settings_changed" } });
+
+        Assert.That(msg.Notification, Is.Null,
+            "a data-only push must not attach a visible Notification block");
+        Assert.That(msg.Apns, Is.Not.Null);
+        Assert.That(msg.Apns.Aps.ContentAvailable, Is.True,
+            "iOS needs content-available to wake the app for a silent data push");
+        Assert.That(msg.Data["type"], Is.EqualTo("settings_changed"));
+    }
+
+    [Test]
+    public void BuildMessage_WithTitleOrBody_SetsNotificationBlock()
+    {
+        var msg = PushNotificationService.BuildMessage("tok", "Hello", "World", null);
+
+        Assert.That(msg.Notification, Is.Not.Null);
+        Assert.That(msg.Notification.Title, Is.EqualTo("Hello"));
+        Assert.That(msg.Notification.Body, Is.EqualTo("World"));
+    }
+
+    // Firebase is not configured in tests, so SendToSiteAsync short-circuits
+    // before it queries. The token-selection query it delegates to is exercised
+    // directly via the internal ResolveTargetTokensAsync seam.
+
+    [Test]
+    public async Task ResolveTargetTokens_WithMinBuild_ExcludesOlderBuildsAndIncludesAtOrAbove()
+    {
+        await SeedToken("old-0", sdkSiteId: 7, buildNumber: 0);
+        await SeedToken("old-below", sdkSiteId: 7, buildNumber: 31220);
+        await SeedToken("exact", sdkSiteId: 7, buildNumber: 31221);
+        await SeedToken("newer", sdkSiteId: 7, buildNumber: 40000);
+        await SeedToken("other-site", sdkSiteId: 8, buildNumber: 40000);
+
+        var service = CreateService();
+
+        var tokens = await service.ResolveTargetTokensAsync(7, minBuild: 31221);
+        var picked = tokens.Select(t => t.Token).ToList();
+
+        Assert.That(picked, Is.EquivalentTo(new[] { "exact", "newer" }),
+            "only same-site tokens reporting build >= minBuild must be targeted");
+    }
+
+    [Test]
+    public async Task ResolveTargetTokens_DefaultMinBuildZero_IncludesEveryDevice()
+    {
+        await SeedToken("legacy-0", sdkSiteId: 7, buildNumber: 0);
+        await SeedToken("modern", sdkSiteId: 7, buildNumber: 40000);
+
+        var service = CreateService();
+
+        var tokens = await service.ResolveTargetTokensAsync(7, minBuild: 0);
+
+        Assert.That(tokens.Select(t => t.Token),
+            Is.EquivalentTo(new[] { "legacy-0", "modern" }),
+            "minBuild 0 must keep existing callers unaffected (all devices included)");
+    }
+
+    private PushNotificationService CreateService() =>
+        new(TimePlanningPnDbContext!, Substitute.For<ILogger<PushNotificationService>>());
+
+    private async Task SeedToken(string token, int sdkSiteId, int buildNumber)
+    {
+        var deviceToken = new DeviceToken
+        {
+            SdkSiteId = sdkSiteId,
+            Token = token,
+            Platform = "android",
+            AppBuildNumber = buildNumber
+        };
+        await deviceToken.Create(TimePlanningPnDbContext!);
+    }
 }
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceExtendedTests.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceExtendedTests.cs
index d50a660a..d860757c 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceExtendedTests.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceExtendedTests.cs
@@ -57,7 +57,8 @@ public async Task SetUp()
             _userService,
             _localizationService,
             null,
-            _coreService);
+            _coreService,
+            Substitute.For<TimePlanning.Pn.Services.PushNotificationService.IPushNotificationService>());
     }
 
     // --- GetAvailableSites tests ---
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServicePhoneNumberTests.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServicePhoneNumberTests.cs
index 0fd9607c..89cc46e9 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServicePhoneNumberTests.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServicePhoneNumberTests.cs
@@ -53,7 +53,8 @@ public async Task SetUp()
             _userService,
             _localizationService,
             null,
-            _coreService);
+            _coreService,
+            Substitute.For<TimePlanning.Pn.Services.PushNotificationService.IPushNotificationService>());
     }
 
     [Test]
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceTests.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceTests.cs
index 5fa4d6c9..5efa9e97 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceTests.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/SettingsServiceTests.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
@@ -27,6 +28,7 @@ public class SettingsServiceTests : TestBaseSetup
     private ITimePlanningLocalizationService _localizationService;
     private IEFormCoreService _coreService;
     private IPluginDbOptions<TimePlanningBaseSettings> _options;
+    private TimePlanning.Pn.Services.PushNotificationService.IPushNotificationService _pushNotificationService;
 
     [SetUp]
     public async Task SetUp()
@@ -51,6 +53,9 @@ public async Task SetUp()
             SnapshotEnabled = "0"
         });
 
+        _pushNotificationService =
+            Substitute.For<TimePlanning.Pn.Services.PushNotificationService.IPushNotificationService>();
+
         _settingsService = new TimeSettingService(
             _options,
             TimePlanningPnDbContext,
@@ -58,7 +63,8 @@ public async Task SetUp()
             _userService,
             _localizationService,
             null,
-            _coreService);
+            _coreService,
+            _pushNotificationService);
     }
 
     [Test]
@@ -194,6 +200,41 @@ public async Task UpdateAssignedSite_UpdatesGpsEnabled_Successfully()
         Assert.That(updatedSite.SnapshotEnabled, Is.False);
     }
 
+    [Test]
+    public async Task UpdateAssignedSite_StillSucceeds_WhenPushThrows()
+    {
+        // The settings_changed push is fire-and-forget: a push failure must
+        // never fail the settings update.
+        _pushNotificationService
+            .SendToSiteAsync(
+                Arg.Any<int>(),
+                Arg.Any<string>(),
+                Arg.Any<string>(),
+                Arg.Any<Dictionary<string, string>?>())
+            .Returns(_ => Task.FromException(new Exception("boom")));
+
+        var assignedSite = new AssignedSiteEntity
+        {
+            SiteId = 42,
+            UseGoogleSheetAsDefault = true,
+            CreatedByUserId = 1,
+            UpdatedByUserId = 1
+        };
+        await assignedSite.Create(TimePlanningPnDbContext);
+
+        var updateModel = new AssignedSiteModel
+        {
+            Id = assignedSite.Id,
+            SiteId = 42,
+            UseGoogleSheetAsDefault = true
+        };
+
+        var result = await _settingsService.UpdateAssignedSite(updateModel);
+
+        Assert.That(result.Success, Is.True,
+            "a push failure must not fail the settings update");
+    }
+
     [Test]
     public async Task UpdateAssignedSite_UpdatesGlobalGpsEnabled_Successfully()
     {
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Protos/device_token.proto b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Protos/device_token.proto
index c43e18a5..0ef28022 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Protos/device_token.proto
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Protos/device_token.proto
@@ -9,9 +9,13 @@ option csharp_namespace = "TimePlanning.Pn.Grpc";
 message RegisterDeviceTokenRequest {
   string token = 1;
   string platform = 2;
-  // Ignored since 2026-07: the server resolves the caller's site id from
-  // the JWT. Field retained for wire compatibility with shipped clients.
-  int32 sdk_site_id = 3;
+  // App build number reported by the client at registration. 0 = old/unknown
+  // client that predates this field. Used to version-gate silent pushes.
+  //
+  // Field 3 previously carried sdk_site_id, which the server ignored since
+  // 2026-07 (the caller's site id is resolved from the JWT). The client
+  // repurposed this int32 slot for build_number, so the wire stays identical.
+  int32 build_number = 3;
 }
 
 message UnregisterDeviceTokenRequest {
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/DeviceTokenService.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/DeviceTokenService.cs
index 279e02fb..ad07302e 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/DeviceTokenService.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/DeviceTokenService.cs
@@ -35,7 +35,7 @@ public DeviceTokenService(
         _coreService = coreService;
     }
 
-    public async Task<OperationResult> RegisterForCallerAsync(string token, string platform)
+    public async Task<OperationResult> RegisterForCallerAsync(string token, string platform, int buildNumber = 0)
     {
         var sdkSiteId = await ResolveCallerSdkSiteIdAsync();
         if (sdkSiteId == 0)
@@ -46,7 +46,7 @@ public async Task<OperationResult> RegisterForCallerAsync(string token, string p
                 false, "Could not resolve an active site for the calling user");
         }
 
-        return await RegisterAsync(sdkSiteId, token, platform);
+        return await RegisterAsync(sdkSiteId, token, platform, buildNumber);
     }
 
     /// <summary>
@@ -80,7 +80,7 @@ private async Task<int> ResolveCallerSdkSiteIdAsync()
         return worker.ResolveActiveSdkSiteId() ?? 0;
     }
 
-    public async Task<OperationResult> RegisterAsync(int sdkSiteId, string token, string platform)
+    public async Task<OperationResult> RegisterAsync(int sdkSiteId, string token, string platform, int buildNumber = 0)
     {
         try
         {
@@ -91,6 +91,7 @@ public async Task<OperationResult> RegisterAsync(int sdkSiteId, string token, st
             {
                 existing.SdkSiteId = sdkSiteId;
                 existing.Platform = platform;
+                existing.AppBuildNumber = buildNumber;
                 await existing.Update(_dbContext);
             }
             else
@@ -100,6 +101,7 @@ public async Task<OperationResult> RegisterAsync(int sdkSiteId, string token, st
                     SdkSiteId = sdkSiteId,
                     Token = token,
                     Platform = platform,
+                    AppBuildNumber = buildNumber,
                 };
                 await deviceToken.Create(_dbContext);
             }
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/IDeviceTokenService.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/IDeviceTokenService.cs
index 4b36af79..38206f22 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/IDeviceTokenService.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/DeviceTokenService/IDeviceTokenService.cs
@@ -9,9 +9,11 @@ public interface IDeviceTokenService
     /// Registers a device token for the authenticated caller. The SDK site id
     /// is resolved server-side from the JWT (client-sent ids are ignored).
     /// Fails without storing anything when no active site resolves.
+    /// <paramref name="buildNumber"/> is the client's app build number
+    /// (0 = old/unknown), stored for push version-gating.
     /// </summary>
-    Task<OperationResult> RegisterForCallerAsync(string token, string platform);
+    Task<OperationResult> RegisterForCallerAsync(string token, string platform, int buildNumber = 0);
 
-    Task<OperationResult> RegisterAsync(int sdkSiteId, string token, string platform);
+    Task<OperationResult> RegisterAsync(int sdkSiteId, string token, string platform, int buildNumber = 0);
     Task<OperationResult> UnregisterAsync(string token);
 }
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/GrpcServices/TimePlanningDeviceTokenGrpcService.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/GrpcServices/TimePlanningDeviceTokenGrpcService.cs
index 7d3b528c..70c7e755 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/GrpcServices/TimePlanningDeviceTokenGrpcService.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/GrpcServices/TimePlanningDeviceTokenGrpcService.cs
@@ -21,10 +21,11 @@ public override async Task<OperationResponse> RegisterDeviceToken(
     {
         try
         {
-            // request.SdkSiteId is deliberately ignored: the site id is
-            // resolved server-side from the JWT (see DeviceTokenService).
+            // The site id is resolved server-side from the JWT (see
+            // DeviceTokenService); the client no longer sends one. The client's
+            // reported app build number is persisted for push version-gating.
             var result = await _deviceTokenService.RegisterForCallerAsync(
-                request.Token, request.Platform);
+                request.Token, request.Platform, request.BuildNumber);
 
             return new OperationResponse
             {
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/IPushNotificationService.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/IPushNotificationService.cs
index 3e9e31f4..7a9e1d51 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/IPushNotificationService.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/IPushNotificationService.cs
@@ -5,5 +5,11 @@ namespace TimePlanning.Pn.Services.PushNotificationService;
 
 public interface IPushNotificationService
 {
-    Task SendToSiteAsync(int targetSdkSiteId, string title, string body, Dictionary<string, string>? data = null);
+    /// <summary>
+    /// Sends a push to every registered device of <paramref name="targetSdkSiteId"/>.
+    /// <paramref name="minBuild"/> gates delivery to devices whose reported
+    /// AppBuildNumber is &gt;= the value; the default of 0 includes every device
+    /// (including old installs that report 0), so existing callers are unaffected.
+    /// </summary>
+    Task SendToSiteAsync(int targetSdkSiteId, string title, string body, Dictionary<string, string>? data = null, int minBuild = 0);
 }
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/PushNotificationService.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/PushNotificationService.cs
index ab7501e9..7004e101 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/PushNotificationService.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/PushNotificationService/PushNotificationService.cs
@@ -11,6 +11,7 @@ namespace TimePlanning.Pn.Services.PushNotificationService;
 using Microsoft.Extensions.Logging;
 using Microting.eForm.Infrastructure.Constants;
 using Microting.TimePlanningBase.Infrastructure.Data;
+using DeviceToken = Microting.TimePlanningBase.Infrastructure.Data.Entities.DeviceToken;
 
 public class PushNotificationService : IPushNotificationService
 {
@@ -57,11 +58,65 @@ public PushNotificationService(
         }
     }
 
+    /// <summary>
+    /// Builds an FCM message. When both <paramref name="title"/> and
+    /// <paramref name="body"/> are empty the message is data-only (silent): no
+    /// visible <see cref="Notification"/> block is attached and APNs
+    /// content-available is set so iOS wakes the app in the background to
+    /// process the data payload. Otherwise a normal visible notification is
+    /// attached alongside the data.
+    /// </summary>
+    public static Message BuildMessage(
+        string token,
+        string title,
+        string body,
+        Dictionary<string, string>? data)
+    {
+        var hasNotification = !string.IsNullOrEmpty(title) || !string.IsNullOrEmpty(body);
+        var message = new Message
+        {
+            Token = token,
+            Data = data
+        };
+
+        if (hasNotification)
+        {
+            message.Notification = new Notification
+            {
+                Title = title,
+                Body = body
+            };
+        }
+        else
+        {
+            message.Apns = new ApnsConfig
+            {
+                Aps = new Aps { ContentAvailable = true }
+            };
+        }
+
+        return message;
+    }
+
+    /// <summary>
+    /// Resolves the live device tokens targeted by a push: same site, still in
+    /// the Created workflow state, and reporting an app build number at or above
+    /// <paramref name="minBuild"/>. A <paramref name="minBuild"/> of 0 includes
+    /// every device (old installs report AppBuildNumber 0).
+    /// </summary>
+    internal Task<List<DeviceToken>> ResolveTargetTokensAsync(int targetSdkSiteId, int minBuild) =>
+        _dbContext.DeviceTokens
+            .Where(dt => dt.SdkSiteId == targetSdkSiteId
+                         && dt.WorkflowState == Constants.WorkflowStates.Created
+                         && dt.AppBuildNumber >= minBuild)
+            .ToListAsync();
+
     public async Task SendToSiteAsync(
         int targetSdkSiteId,
         string title,
         string body,
-        Dictionary<string, string>? data = null)
+        Dictionary<string, string>? data = null,
+        int minBuild = 0)
     {
         if (!_isEnabled)
         {
@@ -73,9 +128,7 @@ public async Task SendToSiteAsync(
 
         try
         {
-            var tokens = await _dbContext.DeviceTokens
-                .Where(dt => dt.SdkSiteId == targetSdkSiteId && dt.WorkflowState == Constants.WorkflowStates.Created)
-                .ToListAsync();
+            var tokens = await ResolveTargetTokensAsync(targetSdkSiteId, minBuild);
 
             if (tokens.Count == 0)
             {
@@ -87,16 +140,7 @@ public async Task SendToSiteAsync(
             {
                 try
                 {
-                    var message = new Message
-                    {
-                        Token = deviceToken.Token,
-                        Notification = new Notification
-                        {
-                            Title = title,
-                            Body = body
-                        },
-                        Data = data
-                    };
+                    var message = BuildMessage(deviceToken.Token, title, body, data);
 
                     await FirebaseMessaging.DefaultInstance.SendAsync(message);
                 }
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/TimePlanningSettingService/TimeSettingService.cs b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/TimePlanningSettingService/TimeSettingService.cs
index d15ba743..7bec78d5 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/TimePlanningSettingService/TimeSettingService.cs
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/TimePlanningSettingService/TimeSettingService.cs
@@ -45,6 +45,7 @@ namespace TimePlanning.Pn.Services.TimePlanningSettingService;
 using Microting.TimePlanningBase.Infrastructure.Data;
 using Microting.TimePlanningBase.Infrastructure.Data.Entities;
 using TimePlanningLocalizationService;
+using TimePlanning.Pn.Services.PushNotificationService;
 
 public class TimeSettingService(
     IPluginDbOptions<TimePlanningBaseSettings> options,
@@ -53,9 +54,15 @@ public class TimeSettingService(
     IUserService userService,
     ITimePlanningLocalizationService localizationService,
     BaseDbContext baseDbContext,
-    IEFormCoreService core)
+    IEFormCoreService core,
+    IPushNotificationService pushNotificationService)
     : ISettingService
 {
+    // First flutter-time build that sends build_number AND handles the
+    // settings_changed silent push; older installs report AppBuildNumber 0 and
+    // are excluded to avoid a stray notification.
+    private const int MinSettingsChangedPushBuild = 31221;
+
     public async Task<OperationDataResult<TimePlanningSettingsModel>> GetSettings()
     {
         try
@@ -1077,6 +1084,25 @@ public async Task<OperationResult> UpdateAssignedSite(Infrastructure.Models.Sett
 
         await dbAssignedSite.Update(dbContext);
 
+        // Fire-and-forget: tell the worker's device(s) that their assigned-site
+        // settings changed so personal mode can auto-refresh. Sent AFTER the row
+        // is committed; a push failure must NEVER fail the settings update.
+        try
+        {
+            await pushNotificationService.SendToSiteAsync(
+                dbAssignedSite.SiteId,
+                title: "",
+                body: "",
+                data: new Dictionary<string, string> { { "type", "settings_changed" } },
+                minBuild: MinSettingsChangedPushBuild);
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(ex,
+                "Failed to send settings_changed push for SdkSiteId {SdkSiteId}",
+                dbAssignedSite.SiteId);
+        }
+
         // Update managing tags
         var existingManagingTags = await dbContext.AssignedSiteManagingTags
             .Where(x => x.AssignedSiteId == dbAssignedSite.Id)
diff --git a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/TimePlanning.Pn.csproj b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/TimePlanning.Pn.csproj
index aef39ee0..f2218b80 100644
--- a/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/TimePlanning.Pn.csproj
+++ b/eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/TimePlanning.Pn.csproj
@@ -33,7 +33,7 @@
       <PackageReference Include="Microting.EformAngularFrontendBase" Version="10.0.36" />
       <PackageReference Include="Microting.eFormApi.BasePn" Version="10.0.31" />
       <PackageReference Include="McMaster.NETCore.Plugins" Version="2.0.0" />
-      <PackageReference Include="Microting.TimePlanningBase" Version="10.0.57" />
+      <PackageReference Include="Microting.TimePlanningBase" Version="10.0.58" />
       <PackageReference Include="Sentry" Version="6.8.0" />
       <PackageReference Include="FirebaseAdmin" Version="3.6.0" />
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