diff --git a/samples/app-HR-talent/csharp/src/Services/GraphApiService.cs b/samples/app-HR-talent/csharp/src/Services/GraphApiService.cs
index 29e8c8cc90..8e26c4d873 100644
--- a/samples/app-HR-talent/csharp/src/Services/GraphApiService.cs
+++ b/samples/app-HR-talent/csharp/src/Services/GraphApiService.cs
@@ -58,7 +58,7 @@ public GraphApiService(
             var installedApps = await graphClient.Users[upn].Teamwork.InstalledApps
                 .Request()
                 .Filter($"teamsApp/externalId eq '{_configuration["TeamsAppId"]}'")
-                .Expand("teamsApp")
+                .Expand("teamsAppDefinition")
                 .GetAsync(cancellationToken);
 
             var app = installedApps.FirstOrDefault();
diff --git a/samples/graph-activity-feed-broadcast/csharp/ActivityFeedBroadcast/Controllers/HomeController.cs b/samples/graph-activity-feed-broadcast/csharp/ActivityFeedBroadcast/Controllers/HomeController.cs
index d045c80069..95346a3cb0 100644
--- a/samples/graph-activity-feed-broadcast/csharp/ActivityFeedBroadcast/Controllers/HomeController.cs
+++ b/samples/graph-activity-feed-broadcast/csharp/ActivityFeedBroadcast/Controllers/HomeController.cs
@@ -123,7 +123,7 @@ await UtilityHelper.ForEachAsync(usersList, partitionCount, async users => {
                     {
                         var installedApp = await graphClient.Users[users.Id].Teamwork.InstalledApps
                                              .Request()
-                                             .Expand("teamsApp")
+                                             .Expand("teamsAppDefinition")
                                              .GetAsync();
 
                         var response = new HttpResponseMessage();
diff --git a/samples/tab-request-approval/csharp/TabRequestApproval/Controllers/HomeController.cs b/samples/tab-request-approval/csharp/TabRequestApproval/Controllers/HomeController.cs
index f8074bf155..5f3edf0d3c 100644
--- a/samples/tab-request-approval/csharp/TabRequestApproval/Controllers/HomeController.cs
+++ b/samples/tab-request-approval/csharp/TabRequestApproval/Controllers/HomeController.cs
@@ -123,13 +123,13 @@ public async Task<ActionResult> SendNotificationToManager(RequestInfo taskInfo)
                               .GetAsync();
 
                     // Retrieve installed apps for the user from Microsoft Graph API
-                    var installedApps = await graphClient.Users[user.Id].Teamwork.InstalledApps
+                    var installedApps = await graphClient.Users[user.UserPrincipalName].Teamwork.InstalledApps
                                        .Request()
-                                       .Expand("teamsApp")
+                                       .Expand("teamsAppDefinition")
                                        .GetAsync();
 
                     // Filter installed apps to find the one with DisplayName "Tab Request Approval"
-                    var installationId = installedApps.Where(id => id.TeamsApp.DisplayName == "Tab Request Approval").Select(x => x.TeamsApp.Id);
+                    var installationId = installedApps.Where(id => id.TeamsAppDefinition.DisplayName == "Tab Request Approval").Select(x => x.TeamsAppDefinition.Id);
 
                     // Check if there is at least one matching installationId
                     if (installationId.Any())
@@ -153,13 +153,13 @@ public async Task<ActionResult> SendNotificationToManager(RequestInfo taskInfo)
 
                         // Create template parameters for the notification
                         var templateParameters = new List<Microsoft.Graph.KeyValuePair>()
-                        {
-                            new Microsoft.Graph.KeyValuePair
-                            {
-                                Name = "approvalTaskId",
-                                Value = taskInfo.title
-                            }
-                        };
+                {
+                    new Microsoft.Graph.KeyValuePair
+                    {
+                        Name = "approvalTaskId",
+                        Value = taskInfo.title
+                    }
+                };
                         // Send the activity notification using Microsoft Graph API
                         await graphClient.Users[user.Id].Teamwork
                             .SendActivityNotification(topic, "approvalRequired", null, previewText, templateParameters)