diff --git a/src/Common.CoreLib/Extensions/HttpExtensions.cs b/src/Common.CoreLib/Extensions/HttpExtensions.cs
new file mode 100644
index 000000000..ea28ad20c
--- /dev/null
+++ b/src/Common.CoreLib/Extensions/HttpExtensions.cs
@@ -0,0 +1,87 @@
+using System.Net;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+// ReSharper disable once CheckNamespace
+namespace System
+{
+    public static class HttpExtensions
+    {
+        #region UseDefaultSendX 使用此扩展代替 Send，将 DefaultRequestVersion 与 DefaultVersionPolicy 赋值给 HttpRequestMessage
+
+#if NETSTANDARD
+        public static Version DefaultRequestVersion { get; set; } = HttpVersion.Version20;
+#endif
+
+        static void UseDefault(HttpClient httpClient, HttpRequestMessage request)
+        {
+#if NETSTANDARD
+            request.Version = DefaultRequestVersion;
+#else
+            request.Version = httpClient.DefaultRequestVersion;
+            request.VersionPolicy = httpClient.DefaultVersionPolicy;
+#endif
+        }
+
+        /// <inheritdoc cref="HttpClient.SendAsync(HttpRequestMessage)"/>
+        public static Task<HttpResponseMessage> UseDefaultSendAsync(this HttpClient httpClient, HttpRequestMessage request)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.SendAsync(request);
+        }
+
+        /// <inheritdoc cref="HttpClient.SendAsync(HttpRequestMessage, HttpCompletionOption)"/>
+        public static Task<HttpResponseMessage> UseDefaultSendAsync(this HttpClient httpClient, HttpRequestMessage request, HttpCompletionOption completionOption)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.SendAsync(request, completionOption);
+        }
+
+        /// <inheritdoc cref="HttpClient.SendAsync(HttpRequestMessage, HttpCompletionOption, CancellationToken)"/>
+        public static Task<HttpResponseMessage> UseDefaultSendAsync(this HttpClient httpClient, HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.SendAsync(request, completionOption, cancellationToken);
+        }
+
+        /// <inheritdoc cref="HttpClient.SendAsync(HttpRequestMessage, CancellationToken)"/>
+        public static Task<HttpResponseMessage> UseDefaultSendAsync(this HttpClient httpClient, HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.SendAsync(request, cancellationToken);
+        }
+
+#if NET5_0_OR_GREATER
+        /// <inheritdoc cref="HttpClient.Send(HttpRequestMessage)"/>
+        public static HttpResponseMessage UseDefaultSend(this HttpClient httpClient, HttpRequestMessage request)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.Send(request);
+        }
+
+        /// <inheritdoc cref="HttpClient.Send(HttpRequestMessage, HttpCompletionOption)"/>
+        public static HttpResponseMessage UseDefaultSend(this HttpClient httpClient, HttpRequestMessage request, HttpCompletionOption completionOption)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.Send(request, completionOption);
+        }
+
+        /// <inheritdoc cref="HttpClient.Send(HttpRequestMessage, HttpCompletionOption, CancellationToken)"/>
+        public static HttpResponseMessage UseDefaultSend(this HttpClient httpClient, HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.Send(request, completionOption, cancellationToken);
+        }
+
+        /// <inheritdoc cref="HttpClient.Send(HttpRequestMessage, CancellationToken)"/>
+        public static HttpResponseMessage UseDefaultSend(this HttpClient httpClient, HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            UseDefault(httpClient, request);
+            return httpClient.Send(request, cancellationToken);
+        }
+#endif
+
+        #endregion
+    }
+}
diff --git a/src/ST.Client/UI/ViewModels/Pages/DebugPageViewModel.cs b/src/ST.Client/UI/ViewModels/Pages/DebugPageViewModel.cs
index 4d83f7bbb..ab05d71d1 100644
--- a/src/ST.Client/UI/ViewModels/Pages/DebugPageViewModel.cs
+++ b/src/ST.Client/UI/ViewModels/Pages/DebugPageViewModel.cs
@@ -15,6 +15,8 @@ using System.Globalization;
 using System.IO;
 using System.IO.Pipes;
 using System.Linq;
+using System.Net;
+using System.Net.Http;
 using System.Security;
 using System.Security.Cryptography.X509Certificates;
 using System.Text;
@@ -74,6 +76,9 @@ namespace System.Application.UI.ViewModels
 
         public void DebugButton_Click()
         {
+            TestHttp3Quic();
+            return;
+
             //#if DEBUG
             //            //TestAppUpdate();
             //            //return;
@@ -94,6 +99,29 @@ namespace System.Application.UI.ViewModels
             });
         }
 
+        public async void TestHttp3Quic()
+        {
+            // https://docs.microsoft.com/zh-cn/dotnet/core/extensions/httpclient-http3
+            // https://devblogs.microsoft.com/dotnet/http-3-support-in-dotnet-6
+            using HttpClient httpClient = new()
+            {
+#if NET6_0_OR_GREATER
+                DefaultRequestVersion = HttpVersion.Version30,
+#endif
+            };
+
+            using HttpRequestMessage request = new(HttpMethod.Get, "https://cloudflare-quic.com/");
+            using var response = await httpClient.UseDefaultSendAsync(request);
+
+            var htmlString = await response.Content.ReadAsStringAsync();
+
+            StringBuilder @string = new();
+            @string.AppendFormatLine("request.Version: {0}", request.Version);
+            @string.AppendFormatLine("response.Version: {0}", response.Version);
+            @string.AppendLine(htmlString);
+            DebugString = @string.ToString();
+        }
+
         //static async void TestTextBoxWindow(int state)
         //{
         //    string? value = null;
diff --git a/src/ST.Services.CloudService/Services/CloudService/ApiConnection.cs b/src/ST.Services.CloudService/Services/CloudService/ApiConnection.cs
index 48f85f439..157c36ff6 100644
--- a/src/ST.Services.CloudService/Services/CloudService/ApiConnection.cs
+++ b/src/ST.Services.CloudService/Services/CloudService/ApiConnection.cs
@@ -506,7 +506,6 @@ namespace System.Application.Services.CloudService
 
                 var request = new HttpRequestMessage(method, requestUri)
                 {
-                    Version = HttpVersion.Version20,
                     Content = GetRequestContent(
                        isSecurity,
                        aes,
@@ -555,7 +554,7 @@ namespace System.Application.Services.CloudService
 
                 HandleHttpRequest(request);
 
-                var response = await client.SendAsync(request,
+                var response = await client.UseDefaultSendAsync(request,
                    HttpCompletionOption.ResponseHeadersRead,
                    cancellationToken)
                    .ConfigureAwait(false);
@@ -757,10 +756,7 @@ namespace System.Application.Services.CloudService
             IApiResponse responseResult;
             try
             {
-                var request = new HttpRequestMessage(method, requestUri)
-                {
-                    Version = HttpVersion.Version20,
-                };
+                var request = new HttpRequestMessage(method, requestUri);
 
                 JWTEntity? jwt = null;
 
@@ -773,7 +769,7 @@ namespace System.Application.Services.CloudService
 
                 HandleHttpRequest(request);
 
-                var response = await client.SendAsync(request,
+                var response = await client.UseDefaultSendAsync(request,
                    HttpCompletionOption.ResponseHeadersRead,
                    cancellationToken)
                    .ConfigureAwait(false);
diff --git a/src/Startup2.cs b/src/Startup2.cs
index a187e7299..c521c7e21 100644
--- a/src/Startup2.cs
+++ b/src/Startup2.cs
@@ -275,7 +275,7 @@ namespace System.Application
                     c.DefaultRequestVersion = HttpVersion.Version20;
 #endif
 #if NET5_0_OR_GREATER
-                    c.DefaultVersionPolicy = HttpVersionPolicy.RequestVersionExact;
+                    c.DefaultVersionPolicy = HttpVersionPolicy.RequestVersionOrHigher;
 #endif
                 }, configureHandler:
 #if NETCOREAPP2_1_OR_GREATER
diff --git a/tests/ST.Client.UnitTest/SetupFixture.shared.cs b/tests/ST.Client.UnitTest/SetupFixture.shared.cs
index 1a8024dbf..f1b4722dd 100644
--- a/tests/ST.Client.UnitTest/SetupFixture.shared.cs
+++ b/tests/ST.Client.UnitTest/SetupFixture.shared.cs
@@ -55,7 +55,7 @@ namespace System.Application
         public static void OneTimeTearDownCore()
         {
 #if !Desktop_UnitTest && !__ANDROID__
-             HostsFileTest.DeleteAllTempFileName();
+            HostsFileTest.DeleteAllTempFileName();
 #endif
         }
 
@@ -102,7 +102,7 @@ namespace System.Application
                 c.DefaultRequestVersion = HttpVersion.Version20;
 #endif
 #if NET5_0_OR_GREATER
-                c.DefaultVersionPolicy = HttpVersionPolicy.RequestVersionExact;
+                c.DefaultVersionPolicy = HttpVersionPolicy.RequestVersionOrHigher;
 #endif
             }, configureHandler:
 #if NETCOREAPP2_1_OR_GREATER