diff --git a/Directory.Build.props b/Directory.Build.props
index 68c67c2f64..1c9eb33bd6 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -23,6 +23,8 @@
     <Nullable>enable</Nullable>
     <PackageTags>HealthCheck;HealthChecks;Health</PackageTags>
     <NoWarn>$(NoWarn);1591;IDISP013</NoWarn> <!--TODO: temporary solution-->
+    <CheckEolTargetFramework>false</CheckEolTargetFramework>
+    <SuppressTfmSupportBuildWarnings>true</SuppressTfmSupportBuildWarnings>
   </PropertyGroup>
 
   <PropertyGroup Condition="$(MSBuildProjectName.EndsWith('.Tests'))">
diff --git a/samples/HealthChecks.UI.Branding/Startup.cs b/samples/HealthChecks.UI.Branding/Startup.cs
index 274213a0c6..4a76026c52 100644
--- a/samples/HealthChecks.UI.Branding/Startup.cs
+++ b/samples/HealthChecks.UI.Branding/Startup.cs
@@ -11,7 +11,6 @@ public class Startup
     // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
     public void ConfigureServices(IServiceCollection services)
     {
-
         //To add authentication and authorization using demo identityserver uncomment AddDemoAuthentication and RequireAuthorization lines
 
         services
@@ -44,10 +43,11 @@ public void ConfigureServices(IServiceCollection services)
 
                 //Webhook endpoint with default failure and description messages
 
-                setup.AddWebhookNotification("webhook1", uri: "https://healthchecks.requestcatcher.com/",
-                                             payload: "{ message: \"Webhook report for [[LIVENESS]]: [[FAILURE]] - Description: [[DESCRIPTIONS]]\"}",
-                                             restorePayload: "{ message: \"[[LIVENESS]] is back to life\"}");
-
+                setup.AddWebhookNotification(
+                    name: "webhook1",
+                    uri: "https://healthchecks.requestcatcher.com/",
+                    payload: "{ message: \"Webhook report for [[LIVENESS]]: [[FAILURE]] - Description: [[DESCRIPTIONS]]\"}",
+                    restorePayload: "{ message: \"[[LIVENESS]] is back to life\"}");
             }).AddInMemoryStorage()
               .Services
             .AddControllers();
diff --git a/src/HealthChecks.Publisher.Prometheus/DependencyInjection/PrometheusGatewayHealthCheckBuilderExtensions.cs b/src/HealthChecks.Publisher.Prometheus/DependencyInjection/PrometheusGatewayHealthCheckBuilderExtensions.cs
index fa43ecf2e5..3963fd79ee 100644
--- a/src/HealthChecks.Publisher.Prometheus/DependencyInjection/PrometheusGatewayHealthCheckBuilderExtensions.cs
+++ b/src/HealthChecks.Publisher.Prometheus/DependencyInjection/PrometheusGatewayHealthCheckBuilderExtensions.cs
@@ -25,9 +25,7 @@ public static IHealthChecksBuilder AddPrometheusGatewayPublisher(
         string? instance = null)
     {
         builder.Services
-            .AddHttpClient();
-
-        builder.Services
+            .AddHttpClient()
             .AddSingleton<IHealthCheckPublisher>(sp => new PrometheusGatewayPublisher(() => sp.GetRequiredService<IHttpClientFactory>().CreateClient(), endpoint, job, instance));
 
         return builder;
diff --git a/src/HealthChecks.SignalR/DependencyInjection/SignalRHealthCheckBuilderExtensions.cs b/src/HealthChecks.SignalR/DependencyInjection/SignalRHealthCheckBuilderExtensions.cs
index a21baa84df..33711feb25 100644
--- a/src/HealthChecks.SignalR/DependencyInjection/SignalRHealthCheckBuilderExtensions.cs
+++ b/src/HealthChecks.SignalR/DependencyInjection/SignalRHealthCheckBuilderExtensions.cs
@@ -32,7 +32,7 @@ public static IHealthChecksBuilder AddSignalRHub(
         IEnumerable<string>? tags = default,
         TimeSpan? timeout = default)
     {
-        Func<HubConnection> hubConnectionBuilder = () =>
+        HubConnection hubConnectionBuilder() =>
             new HubConnectionBuilder()
                 .WithUrl(url)
                 .Build();
@@ -40,7 +40,7 @@ public static IHealthChecksBuilder AddSignalRHub(
         return builder.Add(
             new HealthCheckRegistration(
                 name ?? NAME,
-                sp => new SignalRHealthCheck(hubConnectionBuilder),
+                _ => new SignalRHealthCheck(hubConnectionBuilder),
                 failureStatus,
                 tags,
                 timeout));
@@ -70,7 +70,7 @@ public static IHealthChecksBuilder AddSignalRHub(
         return builder.Add(
             new HealthCheckRegistration(
                 name ?? NAME,
-                sp => new SignalRHealthCheck(hubConnectionBuilder),
+                _ => new SignalRHealthCheck(hubConnectionBuilder),
                 failureStatus,
                 tags,
                 timeout));
diff --git a/src/HealthChecks.UI/Core/UIResourceMapper.cs b/src/HealthChecks.UI/Core/UIResourceMapper.cs
index b0f2aeb060..9b2ec80432 100644
--- a/src/HealthChecks.UI/Core/UIResourceMapper.cs
+++ b/src/HealthChecks.UI/Core/UIResourceMapper.cs
@@ -38,7 +38,7 @@ public void Map(IApplicationBuilder app, Options options)
                     context.Response.OnStarting(() =>
                     {
                         // prevent user add previous middleware in the pipeline
-                        // and set the cache-control 
+                        // and set the cache-control
 
                         if (!context.Response.Headers.ContainsKey("Cache-Control"))
                         {
diff --git a/test/HealthChecks.Publisher.Datadog.Tests/DependencyInjection/RegistrationTests.cs b/test/HealthChecks.Publisher.Datadog.Tests/DependencyInjection/RegistrationTests.cs
index a8fac7b943..6ae738363b 100644
--- a/test/HealthChecks.Publisher.Datadog.Tests/DependencyInjection/RegistrationTests.cs
+++ b/test/HealthChecks.Publisher.Datadog.Tests/DependencyInjection/RegistrationTests.cs
@@ -5,10 +5,10 @@ public class datadog_publisher_registration_should
     [Fact]
     public void add_healthcheck_when_properly_configured()
     {
-        var services = new ServiceCollection();
-        services
+        var services = new ServiceCollection()
             .AddHealthChecks()
-            .AddDatadogPublisher(serviceCheckName: "serviceCheckName", datadogAgentName: "127.0.0.1");
+            .AddDatadogPublisher(serviceCheckName: "serviceCheckName", datadogAgentName: "127.0.0.1")
+            .Services;
 
         using var serviceProvider = services.BuildServiceProvider();
         var publisher = serviceProvider.GetService<IHealthCheckPublisher>();
diff --git a/test/HealthChecks.Publisher.Prometheus.Tests/DependencyInjection/RegistrationTests.cs b/test/HealthChecks.Publisher.Prometheus.Tests/DependencyInjection/RegistrationTests.cs
index ee11b50a2e..a56696f3a4 100644
--- a/test/HealthChecks.Publisher.Prometheus.Tests/DependencyInjection/RegistrationTests.cs
+++ b/test/HealthChecks.Publisher.Prometheus.Tests/DependencyInjection/RegistrationTests.cs
@@ -3,13 +3,13 @@ namespace HealthChecks.Publisher.ApplicationInsights.Tests.DependencyInjection;
 public class prometheus_publisher_registration_should
 {
     [Fact]
-    [System.Obsolete]
+    [Obsolete("AddPrometheusGatewayPublisher is obsolete")]
     public void add_healthcheck_when_properly_configured()
     {
-        var services = new ServiceCollection();
-        services
+        var services = new ServiceCollection()
             .AddHealthChecks()
-            .AddPrometheusGatewayPublisher("http://endpoint.com", "job_name");
+            .AddPrometheusGatewayPublisher("http://endpoint.com", "job_name")
+            .Services;
 
         using var serviceProvider = services.BuildServiceProvider();
         var publisher = serviceProvider.GetService<IHealthCheckPublisher>();
diff --git a/test/HealthChecks.SqlServer.Tests/DependencyInjection/RegistrationTests.cs b/test/HealthChecks.SqlServer.Tests/DependencyInjection/RegistrationTests.cs
index 4c10b4be68..1d4eb0af86 100644
--- a/test/HealthChecks.SqlServer.Tests/DependencyInjection/RegistrationTests.cs
+++ b/test/HealthChecks.SqlServer.Tests/DependencyInjection/RegistrationTests.cs
@@ -7,9 +7,10 @@ public class sql_server_registration_should
     [Fact]
     public void add_health_check_when_properly_configured()
     {
-        var services = new ServiceCollection();
-        services.AddHealthChecks()
-            .AddSqlServer("connectionstring");
+        var services = new ServiceCollection()
+            .AddHealthChecks()
+            .AddSqlServer("connectionstring")
+            .Services;
 
         using var serviceProvider = services.BuildServiceProvider();
         var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>();
@@ -27,11 +28,11 @@ public void invoke_beforeOpen_when_defined()
         var services = new ServiceCollection();
         bool invoked = false;
         const string connectionstring = "Server=(local);Database=foo;User Id=bar;Password=baz;Connection Timeout=1";
-        Action<SqlConnection> beforeOpen = connection =>
+        void beforeOpen(SqlConnection connection)
         {
             invoked = true;
             connection.ConnectionString.ShouldBe(connectionstring);
-        };
+        }
         services.AddHealthChecks()
             .AddSqlServer(connectionstring, configure: beforeOpen);
 
@@ -48,9 +49,10 @@ public void invoke_beforeOpen_when_defined()
     [Fact]
     public void add_named_health_check_when_properly_configured()
     {
-        var services = new ServiceCollection();
-        services.AddHealthChecks()
-            .AddSqlServer("connectionstring", name: "my-sql-server-1");
+        var services = new ServiceCollection()
+            .AddHealthChecks()
+            .AddSqlServer("connectionstring", name: "my-sql-server-1")
+            .Services;
 
         using var serviceProvider = services.BuildServiceProvider();
         var options = serviceProvider.GetRequiredService<IOptions<HealthCheckServiceOptions>>();
@@ -66,7 +68,7 @@ public void add_named_health_check_when_properly_configured()
     public void add_health_check_with_connection_string_factory_when_properly_configured()
     {
         var services = new ServiceCollection();
-        var factoryCalled = false;
+        bool factoryCalled = false;
         services.AddHealthChecks()
             .AddSqlServer(_ =>
             {