diff --git a/CryptoExchange.Net.UnitTests/AsyncResetEventTests.cs b/CryptoExchange.Net.UnitTests/AsyncResetEventTests.cs
index 8fb13bc..672cfb3 100644
--- a/CryptoExchange.Net.UnitTests/AsyncResetEventTests.cs
+++ b/CryptoExchange.Net.UnitTests/AsyncResetEventTests.cs
@@ -96,7 +96,7 @@ namespace CryptoExchange.Net.UnitTests
                 waiters.Add(evnt.WaitAsync());
             }
 
-            List<bool> results = null;
+            List<bool>? results = null;
             var resultsWaiter = Task.Run(async () =>
             {
                 await Task.WhenAll(waiters);
@@ -112,7 +112,7 @@ namespace CryptoExchange.Net.UnitTests
 
             await resultsWaiter;
 
-            Assert.That(10 == results.Count(r => r));
+            Assert.That(10 == results?.Count(r => r));
         }
 
         [Test]
diff --git a/CryptoExchange.Net.UnitTests/BodySerializationTests.cs b/CryptoExchange.Net.UnitTests/BodySerializationTests.cs
new file mode 100644
index 0000000..97947a1
--- /dev/null
+++ b/CryptoExchange.Net.UnitTests/BodySerializationTests.cs
@@ -0,0 +1,43 @@
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using CryptoExchange.Net;
+using CryptoExchange.Net.Objects;
+using CryptoExchange.Net.Converters.SystemTextJson;
+
+namespace CryptoExchange.Net.UnitTests
+{
+    internal class BodySerializationTests
+    {
+        [Test]
+        public void ToFormData_SerializesBasicValuesCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", "1" },
+                { "b", 2 },
+                { "c", true }
+            };
+
+            var parameterString = parameters.ToFormData();
+
+            Assert.That(parameterString, Is.EqualTo("a=1&b=2&c=True"));
+        }
+
+        [Test]
+        public void JsonSerializer_SerializesBasicValuesCorrectly()
+        {
+            var serializer = new SystemTextJsonMessageSerializer(SerializerOptions.WithConverters(new TestSerializerContext()));
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", "1" },
+                { "b", 2 },
+                { "c", true }
+            };
+
+            var parameterString = serializer.Serialize(parameters);
+            Assert.That(parameterString, Is.EqualTo("{\"a\":\"1\",\"b\":2,\"c\":true}"));
+        }
+    }
+}
diff --git a/CryptoExchange.Net.UnitTests/CallResultTests.cs b/CryptoExchange.Net.UnitTests/CallResultTests.cs
index a0daea0..27860bb 100644
--- a/CryptoExchange.Net.UnitTests/CallResultTests.cs
+++ b/CryptoExchange.Net.UnitTests/CallResultTests.cs
@@ -16,7 +16,7 @@ namespace CryptoExchange.Net.UnitTests
         {
             var result = new CallResult(new ServerError("TestError", ErrorInfo.Unknown));
 
-            ClassicAssert.AreSame(result.Error.ErrorCode, "TestError");
+            ClassicAssert.AreSame(result.Error!.ErrorCode, "TestError");
             ClassicAssert.IsFalse(result);
             ClassicAssert.IsFalse(result.Success);
         }
@@ -36,7 +36,7 @@ namespace CryptoExchange.Net.UnitTests
         {
             var result = new CallResult<object>(new ServerError("TestError", ErrorInfo.Unknown));
 
-            ClassicAssert.AreSame(result.Error.ErrorCode, "TestError");
+            ClassicAssert.AreSame(result.Error!.ErrorCode, "TestError");
             ClassicAssert.IsNull(result.Data);
             ClassicAssert.IsFalse(result);
             ClassicAssert.IsFalse(result.Success);
@@ -73,7 +73,7 @@ namespace CryptoExchange.Net.UnitTests
             var asResult = result.As<TestObject2>(default);
 
             ClassicAssert.IsNotNull(asResult.Error);
-            ClassicAssert.AreSame(asResult.Error.ErrorCode, "TestError");
+            ClassicAssert.AreSame(asResult.Error!.ErrorCode, "TestError");
             ClassicAssert.IsNull(asResult.Data);
             ClassicAssert.IsFalse(asResult);
             ClassicAssert.IsFalse(asResult.Success);
@@ -86,7 +86,7 @@ namespace CryptoExchange.Net.UnitTests
             var asResult = result.AsError<TestObject2>(new ServerError("TestError2", ErrorInfo.Unknown));
 
             ClassicAssert.IsNotNull(asResult.Error);
-            ClassicAssert.AreSame(asResult.Error.ErrorCode, "TestError2");
+            ClassicAssert.AreSame(asResult.Error!.ErrorCode, "TestError2");
             ClassicAssert.IsNull(asResult.Data);
             ClassicAssert.IsFalse(asResult);
             ClassicAssert.IsFalse(asResult.Success);
@@ -99,7 +99,7 @@ namespace CryptoExchange.Net.UnitTests
             var asResult = result.AsError<TestObject2>(new ServerError("TestError2", ErrorInfo.Unknown));
 
             ClassicAssert.IsNotNull(asResult.Error);
-            ClassicAssert.AreSame(asResult.Error.ErrorCode, "TestError2");
+            ClassicAssert.AreSame(asResult.Error!.ErrorCode, "TestError2");
             ClassicAssert.IsNull(asResult.Data);
             ClassicAssert.IsFalse(asResult);
             ClassicAssert.IsFalse(asResult.Success);
@@ -126,7 +126,7 @@ namespace CryptoExchange.Net.UnitTests
             var asResult = result.AsError<TestObject2>(new ServerError("TestError2", ErrorInfo.Unknown));
 
             ClassicAssert.IsNotNull(asResult.Error);
-            Assert.That(asResult.Error.ErrorCode == "TestError2");
+            Assert.That(asResult.Error!.ErrorCode == "TestError2");
             Assert.That(asResult.ResponseStatusCode == System.Net.HttpStatusCode.OK);
             Assert.That(asResult.ResponseTime == TimeSpan.FromSeconds(1));
             Assert.That(asResult.RequestUrl == "https://test.com/api");
diff --git a/CryptoExchange.Net.UnitTests/ClientTests/RestClientTests.cs b/CryptoExchange.Net.UnitTests/ClientTests/RestClientTests.cs
index ef12157..effa519 100644
--- a/CryptoExchange.Net.UnitTests/ClientTests/RestClientTests.cs
+++ b/CryptoExchange.Net.UnitTests/ClientTests/RestClientTests.cs
@@ -97,7 +97,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             ClassicAssert.IsFalse(result.Success);
             Assert.That(result.Error != null);
             Assert.That(result.Error is DeserializeError);
-            Assert.That(result.Error.Message.Contains(response));
+            Assert.That(result.Error!.Message!.Contains(response));
         }
 
         [TestCase]
@@ -114,7 +114,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             ClassicAssert.IsFalse(result.Success);
             Assert.That(result.Error != null);
             Assert.That(result.Error is ServerError);
-            Assert.That(result.Error.ErrorCode == "123");
+            Assert.That(result.Error!.ErrorCode == "123");
             Assert.That(result.Error.Message == "Invalid request");
         }
 
@@ -186,12 +186,12 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
 
             var requestDefinition = new RequestDefinition(endpoint, HttpMethod.Get);
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
             for (var i = 0; i < 2; i++)
             {
                 var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Request, requestDefinition, "https://test.com", "123", 1, RateLimitingBehaviour.Wait, null, default);
-                bool expected = i == 1 ? expectLimiting ? evnt.DelayTime > TimeSpan.Zero : evnt == null : evnt == null;
+                bool expected = i == 1 ? expectLimiting ? evnt?.DelayTime > TimeSpan.Zero : evnt == null : evnt == null;
                 Assert.That(expected);
             }
         }
@@ -208,7 +208,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             var requestDefinition1 = new RequestDefinition(endpoint1, HttpMethod.Get);
             var requestDefinition2 = new RequestDefinition(endpoint2, HttpMethod.Get);
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
 
             var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Request, requestDefinition1, "https://test.com", "123", 1, RateLimitingBehaviour.Wait, null, default);
@@ -251,12 +251,12 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
 
             var requestDefinition = new RequestDefinition(endpoint, HttpMethod.Get);
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
             for (var i = 0; i < 2; i++)
             {
                 var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Request, requestDefinition, "https://test.com", "123", 1, RateLimitingBehaviour.Wait, null, default);
-                bool expected = i == 1 ? expectLimited ? evnt.DelayTime > TimeSpan.Zero : evnt == null : evnt == null;
+                bool expected = i == 1 ? expectLimited ? evnt?.DelayTime > TimeSpan.Zero : evnt == null : evnt == null;
                 Assert.That(expected);
             }
         }
@@ -271,12 +271,12 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             rateLimiter.AddGuard(new RateLimitGuard(RateLimitGuard.PerEndpoint, new ExactPathsFilter(new[] { "/sapi/test", "/sapi/test2" }), 1, TimeSpan.FromSeconds(0.1), RateLimitWindowType.Fixed));
             var requestDefinition = new RequestDefinition(endpoint, HttpMethod.Get);
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
             for (var i = 0; i < 2; i++)
             {
                 var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Request, requestDefinition, "https://test.com", "123", 1, RateLimitingBehaviour.Wait, null, default);
-                bool expected = i == 1 ? expectLimited ? evnt.DelayTime > TimeSpan.Zero : evnt == null : evnt == null;
+                bool expected = i == 1 ? expectLimited ? evnt?.DelayTime > TimeSpan.Zero : evnt == null : evnt == null;
                 Assert.That(expected);
             }
         }
@@ -295,7 +295,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             var requestDefinition1 = new RequestDefinition(endpoint1, HttpMethod.Get) { Authenticated = key1 != null };
             var requestDefinition2 = new RequestDefinition(endpoint2, HttpMethod.Get) { Authenticated = key2 != null };
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
 
             var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Request, requestDefinition1, "https://test.com", key1, 1, RateLimitingBehaviour.Wait, null, default);
@@ -314,7 +314,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             var requestDefinition1 = new RequestDefinition(endpoint1, HttpMethod.Get);
             var requestDefinition2 = new RequestDefinition(endpoint2, HttpMethod.Get) { Authenticated = true };
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
 
             var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Request, requestDefinition1, "https://test.com", "123", 1, RateLimitingBehaviour.Wait, null, default);
@@ -334,7 +334,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             var requestDefinition1 = new RequestDefinition(endpoint1, HttpMethod.Get);
             var requestDefinition2 = new RequestDefinition(endpoint2, HttpMethod.Get) { Authenticated = true };
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
 
             var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Request, requestDefinition1, host1, "123", 1, RateLimitingBehaviour.Wait, null, default);
@@ -351,7 +351,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             var rateLimiter = new RateLimitGate("Test");
             rateLimiter.AddGuard(new RateLimitGuard(RateLimitGuard.PerHost, new LimitItemTypeFilter(RateLimitItemType.Connection), 1, TimeSpan.FromSeconds(0.1), RateLimitWindowType.Fixed));
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
 
             var result1 = await rateLimiter.ProcessAsync(new TraceLogger(), 1, RateLimitItemType.Connection, new RequestDefinition("1", HttpMethod.Get), host1, "123", 1, RateLimitingBehaviour.Wait, null, default);
@@ -366,7 +366,7 @@ namespace CryptoExchange.Net.UnitTests.ClientTests
             var rateLimiter = new RateLimitGate("Test");
             rateLimiter.AddGuard(new RateLimitGuard(RateLimitGuard.PerHost, new LimitItemTypeFilter(RateLimitItemType.Connection), 1, TimeSpan.FromSeconds(10), RateLimitWindowType.Fixed));
 
-            RateLimitEvent evnt = null;
+            RateLimitEvent? evnt = null;
             rateLimiter.RateLimitTriggered += (x) => { evnt = x; };
             var ct = new CancellationTokenSource(TimeSpan.FromSeconds(0.2));
 
diff --git a/CryptoExchange.Net.UnitTests/ClientTests/SocketClientTests.cs b/CryptoExchange.Net.UnitTests/ClientTests/SocketClientTests.cs
index 9a7f2ea..3d26f5a 100644
--- a/CryptoExchange.Net.UnitTests/ClientTests/SocketClientTests.cs
+++ b/CryptoExchange.Net.UnitTests/ClientTests/SocketClientTests.cs
@@ -4,6 +4,7 @@ using CryptoExchange.Net.UnitTests.Implementations;
 using CryptoExchange.Net.UnitTests.TestImplementations;
 using NUnit.Framework;
 using System;
+using System.Linq;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -27,8 +28,24 @@ namespace CryptoExchange.Net.UnitTests
             Assert.That(1 == client.ApiClient1.ApiOptions.MaxSocketConnections);
         }
 
+        [TestCase(true)]
+        [TestCase(false)]
+        public async Task ConnectSocket_Should_ReturnConnectionResult(bool canConnect)
+        {
+            //arrange
+            var client = new TestSocketClient();
+            var socket = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
+            socket.CanConnect = canConnect;
+
+            //act
+            var connectResult = await client.ApiClient1.SubscribeToUpdatesAsync<TestObject>(x => { }, false, default);
+
+            //assert
+            Assert.That(connectResult.Success == canConnect);
+        }
+
         [TestCase]
-        public async Task Test()
+        public async Task SocketMessages_Should_BeProcessedInDataHandlers()
         {
             var client = new TestSocketClient();
             var socket = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
@@ -43,209 +60,119 @@ namespace CryptoExchange.Net.UnitTests
             {
                 received = x.Data;
                 resetEvent.Set();
-            }, default);
+            }, false, default);
 
             socket.InvokeMessage(strData);
-
             await resetEvent.WaitAsync(TimeSpan.FromSeconds(1));
 
             Assert.That(received != null);
         }
 
-        //[TestCase(true)]
-        //[TestCase(false)]
-        //public void ConnectSocket_Should_ReturnConnectionResult(bool canConnect)
-        //{
-        //    //arrange
-        //    var client = new TestSocketClient();
-        //    var socket = client.CreateSocket();
-        //    socket.CanConnect = canConnect;
+        [TestCase(false)]
+        [TestCase(true)]
+        public async Task SocketMessages_Should_ContainOriginalDataIfEnabled(bool enabled)
+        {
+            // arrange
+            var client = new TestSocketClient(options =>
+            {
+                options.ReconnectInterval = TimeSpan.Zero;
+                options.ExchangeOptions.OutputOriginalData = enabled;
+            });
+            var socket = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
+            var expected = new TestObject() { DecimalData = 1.23M, IntData = 10, StringData = "Some data" };
+            var strData = JsonSerializer.Serialize(expected, new JsonSerializerOptions { TypeInfoResolver = new TestSerializerContext() });
 
-        //    //act
-        //    var connectResult = client.SubClient.ConnectSocketSub(
-        //        new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, ""));
+            string? originalData = null;
+            var resetEvent = new AsyncResetEvent(false);
 
-        //    //assert
-        //    Assert.That(connectResult.Success == canConnect);
-        //}
+            await client.ApiClient1.SubscribeToUpdatesAsync<TestObject>(x =>
+            {
+                originalData = x.OriginalData;
+                resetEvent.Set();
+            }, false, default);
 
-        //[TestCase]
-        //public void SocketMessages_Should_BeProcessedInDataHandlers()
-        //{
-        //    // arrange
-        //    var client = new TestSocketClient(options =>
-        //    {
-        //        options.ReconnectInterval = TimeSpan.Zero;
-        //    });
-        //    var socket = client.CreateSocket();
-        //    socket.CanConnect = true;
-        //    var sub = new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, "");
-        //    var rstEvent = new ManualResetEvent(false);
-        //    Dictionary<string, string> result = null;
+            socket.InvokeMessage(strData);
+            await resetEvent.WaitAsync(TimeSpan.FromSeconds(1));
 
-        //    client.SubClient.ConnectSocketSub(sub);
+            // assert
+            Assert.That(originalData == (enabled ? strData : null));
+        }
 
-        //    var subObj = new TestSubscription<Dictionary<string, string>>(Mock.Of<ILogger>(), (messageEvent) =>
-        //    {
-        //        result = messageEvent.Data;
-        //        rstEvent.Set();
-        //    });
-        //    sub.AddSubscription(subObj);
+        [TestCase()]
+        public async Task UnsubscribingStream_Should_CloseTheSocket()
+        {
+            // arrange
+            var client = new TestSocketClient(options =>
+            {
+                options.ReconnectInterval = TimeSpan.Zero;
+            });
+            var socket = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
 
-        //    // act
-        //    socket.InvokeMessage("{\"property\": \"123\", \"action\": \"update\", \"topic\": \"topic\"}");
-        //    rstEvent.WaitOne(1000);
+            var result = await client.ApiClient1.SubscribeToUpdatesAsync<TestObject>(x => {}, false, default);
 
-        //    // assert
-        //    Assert.That(result["property"] == "123");
-        //}
+            // act
+            await client.UnsubscribeAsync(result.Data);
 
-        //[TestCase(false)]
-        //[TestCase(true)]
-        //public void SocketMessages_Should_ContainOriginalDataIfEnabled(bool enabled)
-        //{
-        //    // arrange
-        //    var client = new TestSocketClient(options =>
-        //    {
-        //        options.ReconnectInterval = TimeSpan.Zero;
-        //        options.SubOptions.OutputOriginalData = enabled;
-        //    });
-        //    var socket = client.CreateSocket();
-        //    socket.CanConnect = true;
-        //    var sub = new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, "");
-        //    var rstEvent = new ManualResetEvent(false);
-        //    string original = null;
+            // assert
+            Assert.That(socket.Connected == false);
+        }
 
-        //    client.SubClient.ConnectSocketSub(sub);
-        //    var subObj = new TestSubscription<Dictionary<string, string>>(Mock.Of<ILogger>(), (messageEvent) =>
-        //    {
-        //        original = messageEvent.OriginalData;
-        //        rstEvent.Set();
-        //    });
-        //    sub.AddSubscription(subObj);
-        //    var msgToSend = JsonSerializer.Serialize(new { topic = "topic", action = "update", property = "123" });
+        [TestCase()]
+        public async Task UnsubscribingAll_Should_CloseAllSockets()
+        {
+            // arrange
+            var client = new TestSocketClient(options =>
+            {
+                options.ReconnectInterval = TimeSpan.Zero;
+            });
+            var socket = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
+            var result = await client.ApiClient1.SubscribeToUpdatesAsync<TestObject>(x => { }, false, default);
 
-        //    // act
-        //    socket.InvokeMessage(msgToSend);
-        //    rstEvent.WaitOne(1000);
+            var socket2 = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
+            var result2 = await client.ApiClient1.SubscribeToUpdatesAsync<TestObject>(x => { }, false, default);
 
-        //    // assert
-        //    Assert.That(original == (enabled ? msgToSend : null));
-        //}
+            // act
+            await client.UnsubscribeAllAsync();
 
-        //[TestCase()]
-        //public void UnsubscribingStream_Should_CloseTheSocket()
-        //{
-        //    // arrange
-        //    var client = new TestSocketClient(options =>
-        //    {
-        //        options.ReconnectInterval = TimeSpan.Zero;
-        //    });
-        //    var socket = client.CreateSocket();
-        //    socket.CanConnect = true;
-        //    var sub = new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, "");
-        //    client.SubClient.ConnectSocketSub(sub);
+            // assert
+            Assert.That(socket.Connected == false);
+            Assert.That(socket2.Connected == false);
+        }
 
-        //    var subscription = new TestSubscription<Dictionary<string, string>>(Mock.Of<ILogger>(), (messageEvent) => { });
-        //    var ups = new UpdateSubscription(sub, subscription);
-        //    sub.AddSubscription(subscription);
+        [TestCase()]
+        public async Task ErrorResponse_ShouldNot_ConfirmSubscription()
+        {
+            // arrange
+            var client = new TestSocketClient(opt =>
+            {
+                opt.OutputOriginalData = true;
+            });
 
-        //    // act
-        //    client.UnsubscribeAsync(ups).Wait();
+            var socket = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
+            var subTask = client.ApiClient1.SubscribeToUpdatesAsync<TestObject>(x => { }, true, default);
 
-        //    // assert
-        //    Assert.That(socket.Connected == false);
-        //}
+            socket.InvokeMessage(JsonSerializer.Serialize(new TestSocketMessage { Id = 1, Data = "ErrorWithSub" }));
 
-        //[TestCase()]
-        //public void UnsubscribingAll_Should_CloseAllSockets()
-        //{
-        //    // arrange
-        //    var client = new TestSocketClient(options => { options.ReconnectInterval = TimeSpan.Zero; });
-        //    var socket1 = client.CreateSocket();
-        //    var socket2 = client.CreateSocket();
-        //    socket1.CanConnect = true;
-        //    socket2.CanConnect = true;
-        //    var sub1 = new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket1), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, "");
-        //    var sub2 = new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket2), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, "");
-        //    client.SubClient.ConnectSocketSub(sub1);
-        //    client.SubClient.ConnectSocketSub(sub2);
-        //    var subscription1 = new TestSubscription<Dictionary<string, string>>(Mock.Of<ILogger>(), (messageEvent) => { });
-        //    var subscription2 = new TestSubscription<Dictionary<string, string>>(Mock.Of<ILogger>(), (messageEvent) => { });
+            var result = await subTask;
 
-        //    sub1.AddSubscription(subscription1);
-        //    sub2.AddSubscription(subscription2);
-        //    var ups1 = new UpdateSubscription(sub1, subscription1);
-        //    var ups2 = new UpdateSubscription(sub2, subscription2);
+            // assert
+            Assert.That(result.Success == false);
+            Assert.That(result.Error!.Message!.Contains("ErrorWithSub"));
+        }
 
-        //    // act
-        //    client.UnsubscribeAllAsync().Wait();
+        [TestCase()]
+        public async Task SuccessResponse_Should_ConfirmSubscription()
+        {
+            var client = new TestSocketClient();
+            var socket = TestHelpers.ConfigureSocketClient(client, "wss://localhost");
+            var subTask = client.ApiClient1.SubscribeToUpdatesAsync<TestObject>(x => { }, true, default);
 
-        //    // assert
-        //    Assert.That(socket1.Connected == false);
-        //    Assert.That(socket2.Connected == false);
-        //}
+            socket.InvokeMessage(JsonSerializer.Serialize(new TestSocketMessage { Id = 1, Data = "OK" }));
 
-        //[TestCase()]
-        //public void FailingToConnectSocket_Should_ReturnError()
-        //{
-        //    // arrange
-        //    var client = new TestSocketClient(options => { options.ReconnectInterval = TimeSpan.Zero; });
-        //    var socket = client.CreateSocket();
-        //    socket.CanConnect = false;
-        //    var sub1 = new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, "");
+            var result = await subTask;
 
-        //    // act
-        //    var connectResult = client.SubClient.ConnectSocketSub(sub1);
-
-        //    // assert
-        //    ClassicAssert.IsFalse(connectResult.Success);
-        //}
-
-        //[TestCase()]
-        //public async Task ErrorResponse_ShouldNot_ConfirmSubscription()
-        //{
-        //    // arrange
-        //    var channel = "trade_btcusd";
-        //    var client = new TestSocketClient(opt =>
-        //    {
-        //        opt.OutputOriginalData = true;
-        //        opt.SocketSubscriptionsCombineTarget = 1;
-        //    });
-        //    var socket = client.CreateSocket();
-        //    socket.CanConnect = true;
-        //    client.SubClient.ConnectSocketSub(new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, ""));
-
-        //    // act
-        //    var sub = client.SubClient.SubscribeToSomethingAsync(channel, onUpdate => { }, ct: default);
-        //    socket.InvokeMessage(JsonSerializer.Serialize(new { channel, action = "subscribe", status = "error" }));
-        //    await sub;
-
-        //    // assert
-        //    ClassicAssert.IsTrue(client.SubClient.TestSubscription.Status != SubscriptionStatus.Subscribed);
-        //}
-
-        //[TestCase()]
-        //public async Task SuccessResponse_Should_ConfirmSubscription()
-        //{
-        //    // arrange
-        //    var channel = "trade_btcusd";
-        //    var client = new TestSocketClient(opt =>
-        //    {
-        //        opt.OutputOriginalData = true;
-        //        opt.SocketSubscriptionsCombineTarget = 1;
-        //    });
-        //    var socket = client.CreateSocket();
-        //    socket.CanConnect = true;
-        //    client.SubClient.ConnectSocketSub(new SocketConnection(new TraceLogger(), new TestWebsocketFactory(socket), new WebSocketParameters(new Uri("https://localhost/"), ReconnectPolicy.Disabled), client.SubClient, ""));
-
-        //    // act
-        //    var sub = client.SubClient.SubscribeToSomethingAsync(channel, onUpdate => { }, ct: default);
-        //    socket.InvokeMessage(JsonSerializer.Serialize(new { channel, action = "subscribe", status = "confirmed" }));
-        //    await sub;
-
-        //    // assert
-        //    Assert.That(client.SubClient.TestSubscription.Status == SubscriptionStatus.Subscribed);
-        //}
+            var subscription = client.ApiClient1._socketConnections.Single().Value.Subscriptions.Single();
+            Assert.That(subscription.Status == SubscriptionStatus.Subscribed);
+        }
     }
 }
diff --git a/CryptoExchange.Net.UnitTests/ConverterTests/ArrayConverterTests.cs b/CryptoExchange.Net.UnitTests/ConverterTests/ArrayConverterTests.cs
index fa822e8..6069359 100644
--- a/CryptoExchange.Net.UnitTests/ConverterTests/ArrayConverterTests.cs
+++ b/CryptoExchange.Net.UnitTests/ConverterTests/ArrayConverterTests.cs
@@ -48,18 +48,18 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
             var serialized = JsonSerializer.Serialize(data);
             var deserialized = JsonSerializer.Deserialize<Test>(serialized);
 
-            Assert.That(deserialized.Prop1, Is.EqualTo(2));
+            Assert.That(deserialized!.Prop1, Is.EqualTo(2));
             Assert.That(deserialized.Prop2, Is.Null);
             Assert.That(deserialized.Prop3, Is.EqualTo("123"));
             Assert.That(deserialized.Prop3Again, Is.EqualTo("123"));
             Assert.That(deserialized.Prop4, Is.Null);
-            Assert.That(deserialized.Prop5.Prop21, Is.EqualTo(3));
-            Assert.That(deserialized.Prop5.Prop22, Is.EqualTo("456"));
-            Assert.That(deserialized.Prop6.Prop31, Is.EqualTo(4));
+            Assert.That(deserialized.Prop5!.Prop21, Is.EqualTo(3));
+            Assert.That(deserialized.Prop5!.Prop22, Is.EqualTo("456"));
+            Assert.That(deserialized.Prop6!.Prop31, Is.EqualTo(4));
             Assert.That(deserialized.Prop6.Prop32, Is.EqualTo("789"));
             Assert.That(deserialized.Prop7, Is.EqualTo(TestEnum.Two));
-            Assert.That(deserialized.TestInternal.Prop1, Is.EqualTo(10));
-            Assert.That(deserialized.Prop8.Prop31, Is.EqualTo(5));
+            Assert.That(deserialized.TestInternal!.Prop1, Is.EqualTo(10));
+            Assert.That(deserialized.Prop8!.Prop31, Is.EqualTo(5));
             Assert.That(deserialized.Prop8.Prop32, Is.EqualTo("101"));
         }
     }
@@ -72,21 +72,21 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         [ArrayProperty(1)]
         public int? Prop2 { get; set; }
         [ArrayProperty(2)]
-        public string Prop3 { get; set; }
+        public string? Prop3 { get; set; }
         [ArrayProperty(2)]
-        public string Prop3Again { get; set; }
+        public string? Prop3Again { get; set; }
         [ArrayProperty(3)]
-        public string Prop4 { get; set; }
+        public string? Prop4 { get; set; }
         [ArrayProperty(4)]
-        public Test2 Prop5 { get; set; }
+        public Test2? Prop5 { get; set; }
         [ArrayProperty(5)]
-        public Test3 Prop6 { get; set; }
+        public Test3? Prop6 { get; set; }
         [ArrayProperty(6), JsonConverter(typeof(EnumConverter<TestEnum>))]
         public TestEnum? Prop7 { get; set; }
         [ArrayProperty(7)]
-        public Test TestInternal { get; set; }
+        public Test? TestInternal { get; set; }
         [ArrayProperty(8), JsonConversion]
-        public Test3 Prop8 { get; set; }
+        public Test3? Prop8 { get; set; }
     }
 
     [JsonConverter(typeof(ArrayConverter<Test2>))]
@@ -95,7 +95,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         [ArrayProperty(0)]
         public int Prop21 { get; set; }
         [ArrayProperty(1)]
-        public string Prop22 { get; set; }
+        public string? Prop22 { get; set; }
     }
 
     public record Test3
@@ -103,7 +103,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         [JsonPropertyName("prop31")]
         public int Prop31 { get; set; }
         [JsonPropertyName("prop32")]
-        public string Prop32 { get; set; }
+        public string? Prop32 { get; set; }
     }
 
 }
diff --git a/CryptoExchange.Net.UnitTests/ConverterTests/BoolConverterTests.cs b/CryptoExchange.Net.UnitTests/ConverterTests/BoolConverterTests.cs
index e0bc121..b65d1ed 100644
--- a/CryptoExchange.Net.UnitTests/ConverterTests/BoolConverterTests.cs
+++ b/CryptoExchange.Net.UnitTests/ConverterTests/BoolConverterTests.cs
@@ -22,7 +22,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         {
             var val = value == null ? "null" : $"\"{value}\"";
             var output = JsonSerializer.Deserialize<STJBoolObject>($"{{ \"Value\": {val} }}", SerializerOptions.WithConverters(new TestSerializerContext()));
-            Assert.That(output.Value == expected);
+            Assert.That(output!.Value == expected);
         }
 
         [TestCase("1", true)]
@@ -41,7 +41,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         {
             var val = value == null ? "null" : $"\"{value}\"";
             var output = JsonSerializer.Deserialize<NotNullableSTJBoolObject>($"{{ \"Value\": {val} }}", SerializerOptions.WithConverters(new TestSerializerContext()));
-            Assert.That(output.Value == expected);
+            Assert.That(output!.Value == expected);
         }
     }
 
diff --git a/CryptoExchange.Net.UnitTests/ConverterTests/DateTimeConverterTests.cs b/CryptoExchange.Net.UnitTests/ConverterTests/DateTimeConverterTests.cs
index 92ed666..4892a05 100644
--- a/CryptoExchange.Net.UnitTests/ConverterTests/DateTimeConverterTests.cs
+++ b/CryptoExchange.Net.UnitTests/ConverterTests/DateTimeConverterTests.cs
@@ -22,7 +22,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         public void TestDateTimeConverterString(string input, bool expectNull = false)
         {
             var output = JsonSerializer.Deserialize<STJTimeObject>($"{{ \"time\": \"{input}\" }}");
-            Assert.That(output.Time == (expectNull ? null : new DateTime(2021, 05, 12, 0, 0, 0, DateTimeKind.Utc)));
+            Assert.That(output!.Time == (expectNull ? null : new DateTime(2021, 05, 12, 0, 0, 0, DateTimeKind.Utc)));
         }
 
         [TestCase(1620777600.000)]
@@ -30,7 +30,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         public void TestDateTimeConverterDouble(double input)
         {
             var output = JsonSerializer.Deserialize<STJTimeObject>($"{{ \"time\": {input} }}");
-            Assert.That(output.Time == new DateTime(2021, 05, 12, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(output!.Time == new DateTime(2021, 05, 12, 0, 0, 0, DateTimeKind.Utc));
         }
 
         [TestCase(1620777600)]
@@ -41,7 +41,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         public void TestDateTimeConverterLong(long input, bool expectNull = false)
         {
             var output = JsonSerializer.Deserialize<STJTimeObject>($"{{ \"time\": {input} }}");
-            Assert.That(output.Time == (expectNull ? null : new DateTime(2021, 05, 12, 0, 0, 0, DateTimeKind.Utc)));
+            Assert.That(output!.Time == (expectNull ? null : new DateTime(2021, 05, 12, 0, 0, 0, DateTimeKind.Utc)));
         }
 
         [TestCase(1620777600)]
@@ -106,7 +106,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         public void TestDateTimeConverterNull()
         {
             var output = JsonSerializer.Deserialize<STJTimeObject>($"{{ \"time\": null }}");
-            Assert.That(output.Time == null);
+            Assert.That(output!.Time == null);
         }
     }
 
diff --git a/CryptoExchange.Net.UnitTests/ConverterTests/DecimalConverterTests.cs b/CryptoExchange.Net.UnitTests/ConverterTests/DecimalConverterTests.cs
index 4503b01..b7302d7 100644
--- a/CryptoExchange.Net.UnitTests/ConverterTests/DecimalConverterTests.cs
+++ b/CryptoExchange.Net.UnitTests/ConverterTests/DecimalConverterTests.cs
@@ -23,7 +23,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         public void TestDecimalConverterString(string value, decimal? expected)
         {
             var result = JsonSerializer.Deserialize<STJDecimalObject>("{ \"test\": \"" + value + "\"}");
-            Assert.That(result.Test, Is.EqualTo(expected == -999 ? decimal.MinValue : expected == 999 ? decimal.MaxValue : expected));
+            Assert.That(result!.Test, Is.EqualTo(expected == -999 ? decimal.MinValue : expected == 999 ? decimal.MaxValue : expected));
         }
 
         [TestCase("1", 1)]
@@ -36,7 +36,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         public void TestDecimalConverterNumber(string value, decimal? expected)
         {
             var result = JsonSerializer.Deserialize<STJDecimalObject>("{ \"test\": " + value + "}");
-            Assert.That(result.Test, Is.EqualTo(expected == -999 ? decimal.MaxValue : expected));
+            Assert.That(result!.Test, Is.EqualTo(expected == -999 ? decimal.MaxValue : expected));
         }
     }
 
diff --git a/CryptoExchange.Net.UnitTests/ConverterTests/EnumConverterTests.cs b/CryptoExchange.Net.UnitTests/ConverterTests/EnumConverterTests.cs
index 18a427e..ee9b1d8 100644
--- a/CryptoExchange.Net.UnitTests/ConverterTests/EnumConverterTests.cs
+++ b/CryptoExchange.Net.UnitTests/ConverterTests/EnumConverterTests.cs
@@ -45,7 +45,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         {
             var val = value == null ? "null" : $"\"{value}\"";
             var output = JsonSerializer.Deserialize<STJEnumObject>($"{{ \"Value\": {val} }}", SerializerOptions.WithConverters(new TestSerializerContext()));
-            Assert.That(output.Value == expected);
+            Assert.That(output!.Value == expected);
         }
 
         [TestCase("1", TestEnum.One)]
@@ -60,7 +60,7 @@ namespace CryptoExchange.Net.UnitTests.ConverterTests
         {
             var val = value == null ? "null" : $"\"{value}\"";
             var output = JsonSerializer.Deserialize<NotNullableSTJEnumObject>($"{{ \"Value\": {val} }}");
-            Assert.That(output.Value == expected);
+            Assert.That(output!.Value == expected);
         }
 
         [Test]
diff --git a/CryptoExchange.Net.UnitTests/ConverterTests/SharedModelConversionTests.cs b/CryptoExchange.Net.UnitTests/ConverterTests/SharedModelConversionTests.cs
index e910885..d90e33f 100644
--- a/CryptoExchange.Net.UnitTests/ConverterTests/SharedModelConversionTests.cs
+++ b/CryptoExchange.Net.UnitTests/ConverterTests/SharedModelConversionTests.cs
@@ -20,7 +20,7 @@ namespace CryptoExchange.Net.UnitTests
             var serialized = JsonSerializer.Serialize(symbol);
             var restored = JsonSerializer.Deserialize<SharedSymbol>(serialized);
 
-            Assert.That(restored.TradingMode, Is.EqualTo(symbol.TradingMode));
+            Assert.That(restored!.TradingMode, Is.EqualTo(symbol.TradingMode));
             Assert.That(restored.BaseAsset, Is.EqualTo(symbol.BaseAsset));
             Assert.That(restored.QuoteAsset, Is.EqualTo(symbol.QuoteAsset));
             Assert.That(restored.DeliverTime, Is.EqualTo(symbol.DeliverTime));
@@ -38,7 +38,7 @@ namespace CryptoExchange.Net.UnitTests
             var serialized = JsonSerializer.Serialize(symbol);
             var restored = JsonSerializer.Deserialize<SharedOrderQuantity>(serialized);
 
-            Assert.That(restored.QuantityInBaseAsset, Is.EqualTo(symbol.QuantityInBaseAsset));
+            Assert.That(restored!.QuantityInBaseAsset, Is.EqualTo(symbol.QuantityInBaseAsset));
             Assert.That(restored.QuantityInQuoteAsset, Is.EqualTo(symbol.QuantityInQuoteAsset));
             Assert.That(restored.QuantityInContracts, Is.EqualTo(symbol.QuantityInContracts));
         }
diff --git a/CryptoExchange.Net.UnitTests/ExchangeSymbolCacheTests.cs b/CryptoExchange.Net.UnitTests/ExchangeSymbolCacheTests.cs
index c11c41b..61dda9e 100644
--- a/CryptoExchange.Net.UnitTests/ExchangeSymbolCacheTests.cs
+++ b/CryptoExchange.Net.UnitTests/ExchangeSymbolCacheTests.cs
@@ -326,7 +326,7 @@ namespace CryptoExchange.Net.UnitTests
 
             // assert
             Assert.That(result, Is.Not.Null);
-            Assert.That(result.BaseAsset, Is.EqualTo("BTC"));
+            Assert.That(result!.BaseAsset, Is.EqualTo("BTC"));
             Assert.That(result.QuoteAsset, Is.EqualTo("USDT"));
             Assert.That(result.TradingMode, Is.EqualTo(TradingMode.Spot));
             Assert.That(result.SymbolName, Is.EqualTo("BTCUSDT"));
diff --git a/CryptoExchange.Net.UnitTests/Implementations/TestQuery.cs b/CryptoExchange.Net.UnitTests/Implementations/TestQuery.cs
new file mode 100644
index 0000000..4d762dd
--- /dev/null
+++ b/CryptoExchange.Net.UnitTests/Implementations/TestQuery.cs
@@ -0,0 +1,24 @@
+using CryptoExchange.Net.Objects;
+using CryptoExchange.Net.Objects.Errors;
+using CryptoExchange.Net.Sockets;
+using CryptoExchange.Net.Sockets.Default;
+using System;
+
+namespace CryptoExchange.Net.UnitTests.Implementations
+{
+    internal class TestQuery : Query<TestSocketMessage>
+    {
+        public TestQuery(TestSocketMessage request, bool authenticated) : base(request, authenticated, 1)
+        {
+            MessageRouter = MessageRouter.CreateWithoutTopicFilter<TestSocketMessage>(request.Id.ToString(), HandleMessage);
+        }
+
+        private CallResult? HandleMessage(SocketConnection connection, DateTime time, string? arg3, TestSocketMessage message)
+        {
+            if (message.Data != "OK")
+                return new CallResult(new ServerError(ErrorInfo.Unknown with { Message = message.Data }));
+
+            return CallResult.SuccessResult;
+        }
+    }
+}
diff --git a/CryptoExchange.Net.UnitTests/Implementations/TestSerializerContext.cs b/CryptoExchange.Net.UnitTests/Implementations/TestSerializerContext.cs
index dd1b403..b68f3c7 100644
--- a/CryptoExchange.Net.UnitTests/Implementations/TestSerializerContext.cs
+++ b/CryptoExchange.Net.UnitTests/Implementations/TestSerializerContext.cs
@@ -1,4 +1,5 @@
 using CryptoExchange.Net.UnitTests.ConverterTests;
+using CryptoExchange.Net.UnitTests.Implementations;
 using CryptoExchange.Net.UnitTests.TestImplementations;
 using System.Collections.Generic;
 using System.Text.Json.Serialization;
@@ -13,6 +14,7 @@ namespace CryptoExchange.Net.UnitTests
     [JsonSerializable(typeof(IDictionary<string, object>))]
     [JsonSerializable(typeof(TestObject))]
 
+    [JsonSerializable(typeof(TestSocketMessage))]
     [JsonSerializable(typeof(Test))]
     [JsonSerializable(typeof(Test2))]
     [JsonSerializable(typeof(Test3))]
diff --git a/CryptoExchange.Net.UnitTests/Implementations/TestSocketApiClient.cs b/CryptoExchange.Net.UnitTests/Implementations/TestSocketApiClient.cs
index 1bdc8d0..6f4a034 100644
--- a/CryptoExchange.Net.UnitTests/Implementations/TestSocketApiClient.cs
+++ b/CryptoExchange.Net.UnitTests/Implementations/TestSocketApiClient.cs
@@ -36,9 +36,9 @@ namespace CryptoExchange.Net.UnitTests.Implementations
         protected override TestAuthenticationProvider CreateAuthenticationProvider(TestCredentials credentials) =>
             new TestAuthenticationProvider(credentials);
 
-        public async Task<CallResult<UpdateSubscription>> SubscribeToUpdatesAsync<T>(Action<DataEvent<T>> handler, CancellationToken ct)
+        public async Task<CallResult<UpdateSubscription>> SubscribeToUpdatesAsync<T>(Action<DataEvent<T>> handler, bool subQuery, CancellationToken ct)
         {
-            return await base.SubscribeAsync(new TestSubscription<T>(_logger, handler, false), ct);
+            return await base.SubscribeAsync(new TestSubscription<T>(_logger, handler, subQuery, false), ct);
         }
     }
 }
diff --git a/CryptoExchange.Net.UnitTests/Implementations/TestSocketMessage.cs b/CryptoExchange.Net.UnitTests/Implementations/TestSocketMessage.cs
new file mode 100644
index 0000000..5a38b6c
--- /dev/null
+++ b/CryptoExchange.Net.UnitTests/Implementations/TestSocketMessage.cs
@@ -0,0 +1,16 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.Json.Serialization;
+
+namespace CryptoExchange.Net.UnitTests.Implementations
+{
+    internal record TestSocketMessage
+    {
+        [JsonPropertyName("id")]
+        public int Id { get; set; }
+        [JsonPropertyName("data")]
+        public string Data { get; set; } = string.Empty;
+    }
+}
diff --git a/CryptoExchange.Net.UnitTests/Implementations/TestSocketMessageHandler.cs b/CryptoExchange.Net.UnitTests/Implementations/TestSocketMessageHandler.cs
index 201c053..9acc48b 100644
--- a/CryptoExchange.Net.UnitTests/Implementations/TestSocketMessageHandler.cs
+++ b/CryptoExchange.Net.UnitTests/Implementations/TestSocketMessageHandler.cs
@@ -15,8 +15,15 @@ namespace CryptoExchange.Net.UnitTests.Implementations
 
         protected override MessageTypeDefinition[] TypeEvaluators { get; } = [
 
-            new MessageTypeDefinition {
+             new MessageTypeDefinition {
                 ForceIfFound = true,
+                Fields = [
+                    new PropertyFieldReference("id")
+                ],
+                TypeIdentifierCallback = (doc) => doc.FieldValue("id")!
+            },
+
+            new MessageTypeDefinition {
                 Fields = [
                 ],
                 StaticIdentifier = "test"
diff --git a/CryptoExchange.Net.UnitTests/Implementations/TestSubscription.cs b/CryptoExchange.Net.UnitTests/Implementations/TestSubscription.cs
index a8cf1c5..6aa3b4b 100644
--- a/CryptoExchange.Net.UnitTests/Implementations/TestSubscription.cs
+++ b/CryptoExchange.Net.UnitTests/Implementations/TestSubscription.cs
@@ -13,16 +13,31 @@ namespace CryptoExchange.Net.UnitTests.Implementations
     internal class TestSubscription<T> : Subscription
     {
         private readonly Action<DataEvent<T>> _handler;
+        private bool _subQuery;
 
-        public TestSubscription(ILogger logger, Action<DataEvent<T>> handler, bool authenticated) : base(logger, authenticated, true)
+        public TestSubscription(ILogger logger, Action<DataEvent<T>> handler, bool subQuery, bool authenticated) : base(logger, authenticated, true)
         {
             _handler = handler;
+            _subQuery = subQuery;
 
             MessageRouter = MessageRouter.CreateWithoutTopicFilter<T>("test", HandleUpdate);
         }
 
-        protected override Query? GetSubQuery(SocketConnection connection) => null;
-        protected override Query? GetUnsubQuery(SocketConnection connection) => null;
+        protected override Query? GetSubQuery(SocketConnection connection)
+        {
+            if (!_subQuery)
+                return null;
+
+            return new TestQuery(new TestSocketMessage { Id = 1, Data = "Sub" }, false);
+        }
+
+        protected override Query? GetUnsubQuery(SocketConnection connection)
+        {
+            if (!_subQuery)
+                return null;
+
+            return new TestQuery(new TestSocketMessage { Id = 2, Data = "Unsub" }, false);
+        }
 
 
         private CallResult? HandleUpdate(SocketConnection connection, DateTime time, string? originalData, T data)
diff --git a/CryptoExchange.Net.UnitTests/ParameterCollectionTests.cs b/CryptoExchange.Net.UnitTests/ParameterCollectionTests.cs
new file mode 100644
index 0000000..9853c6a
--- /dev/null
+++ b/CryptoExchange.Net.UnitTests/ParameterCollectionTests.cs
@@ -0,0 +1,331 @@
+using CryptoExchange.Net.Objects;
+using CryptoExchange.Net.UnitTests.ConverterTests;
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace CryptoExchange.Net.UnitTests
+{
+    internal class ParameterCollectionTests
+    {
+        [Test]
+        public void AddingBasicValue_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.Add("test", "value");
+            Assert.That(parameters["test"], Is.EqualTo("value"));
+        }
+
+        [Test]
+        public void AddingBasicNullValue_ThrowExecption()
+        {
+            var parameters = new ParameterCollection();
+            Assert.Throws<ArgumentNullException>(() =>  parameters.Add("test", null!));
+        }
+
+        [Test]
+        public void AddingOptionalBasicValue_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptional("test", "value");
+            Assert.That(parameters["test"], Is.EqualTo("value"));
+        }
+
+        [Test]
+        public void AddingOptionalBasicNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptional("test", null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingDecimalValueAsString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddString("test", 0.1m);
+            Assert.That(parameters["test"], Is.EqualTo("0.1"));
+        }
+
+        [Test]
+        public void AddingOptionalDecimalValueAsString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalString("test", 0.1m);
+            Assert.That(parameters["test"], Is.EqualTo("0.1"));
+        }
+
+        [Test]
+        public void AddingOptionalDecimalNullValueAsString_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalString("test", (decimal?)null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingIntValueAsString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddString("test", 1);
+            Assert.That(parameters["test"], Is.EqualTo("1"));
+        }
+
+        [Test]
+        public void AddingOptionalIntValueAsString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalString("test", 1);
+            Assert.That(parameters["test"], Is.EqualTo("1"));
+        }
+
+        [Test]
+        public void AddingOptionalIntNullValueAsString_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalString("test", (int?)null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingLongValueAsString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddString("test", 1L);
+            Assert.That(parameters["test"], Is.EqualTo("1"));
+        }
+
+        [Test]
+        public void AddingOptionalLongValueAsString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalString("test", 1L);
+            Assert.That(parameters["test"], Is.EqualTo("1"));
+        }
+
+        [Test]
+        public void AddingOptionalLongNullValueAsString_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalString("test", (long?)null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingMillisecondTimestamp_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddMilliseconds("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo(1735689600000));
+        }
+
+        [Test]
+        public void AddingOptionalMillisecondTimestamp_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalMilliseconds("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo(1735689600000));
+        }
+
+        [Test]
+        public void AddingOptionalMillisecondNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalMilliseconds("test", null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingMillisecondTimestampString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddMillisecondsString("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo("1735689600000"));
+        }
+
+        [Test]
+        public void AddingOptionalMillisecondTimestampString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalMillisecondsString("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo("1735689600000"));
+        }
+
+        [Test]
+        public void AddingOptionalMillisecondStringNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalMillisecondsString("test", null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingSecondTimestamp_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddSeconds("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo(1735689600));
+        }
+
+        [Test]
+        public void AddingOptionalSecondTimestamp_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalSeconds("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo(1735689600));
+        }
+
+        [Test]
+        public void AddingSecondNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalSeconds("test", null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingSecondTimestampString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddSecondsString("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo("1735689600"));
+        }
+
+        [Test]
+        public void AddingOptionalSecondTimestampString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalSecondsString("test", new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.That(parameters["test"], Is.EqualTo("1735689600"));
+        }
+
+        [Test]
+        public void AddingSecondStringNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalSecondsString("test", null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingEnum_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddEnum("test", TestEnum.Two);
+            Assert.That(parameters["test"], Is.EqualTo("2"));
+        }
+
+        [Test]
+        public void AddingOptionalEnum_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalEnum("test", (TestEnum?)TestEnum.Two);
+            Assert.That(parameters["test"], Is.EqualTo("2"));
+        }
+
+        [Test]
+        public void AddingOptionalEnumNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalEnum("test", (TestEnum?)null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingEnumAsInt_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddEnumAsInt("test", TestEnum.Two);
+            Assert.That(parameters["test"], Is.EqualTo(2));
+        }
+
+        [Test]
+        public void AddingOptionalEnumAsInt_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalEnumAsInt("test", (TestEnum?)TestEnum.Two);
+            Assert.That(parameters["test"], Is.EqualTo(2));
+        }
+
+        [Test]
+        public void AddingOptionalEnumAsIntNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalEnumAsInt("test", (TestEnum?)null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingCommaSeparated_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddCommaSeparated("test", ["1", "2"]);
+            Assert.That(parameters["test"], Is.EqualTo("1,2"));
+        }
+
+        [Test]
+        public void AddingOptionalCommaSeparated_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalCommaSeparated("test", ["1", "2"]);
+            Assert.That(parameters["test"], Is.EqualTo("1,2"));
+        }
+
+        [Test]
+        public void AddingOptionalCommaSeparatedNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalCommaSeparated("test", (string[]?)null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingCommaSeparatedEnum_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddCommaSeparated("test", [TestEnum.Two, TestEnum.One]);
+            Assert.That(parameters["test"], Is.EqualTo("2,1"));
+        }
+
+        [Test]
+        public void AddingOptionalCommaSeparatedEnum_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalCommaSeparated("test", [TestEnum.Two, TestEnum.One]);
+            Assert.That(parameters["test"], Is.EqualTo("2,1"));
+        }
+
+        [Test]
+        public void AddingOptionalCommaSeparatedEnumNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalCommaSeparated("test", (TestEnum[]?)null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+
+        [Test]
+        public void AddingBoolString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddBoolString("test", true);
+            Assert.That(parameters["test"], Is.EqualTo("true"));
+        }
+
+        [Test]
+        public void AddingOptionalBoolString_SetValueCorrectly()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalBoolString("test", true);
+            Assert.That(parameters["test"], Is.EqualTo("true"));
+        }
+
+        [Test]
+        public void AddingOptionalBoolStringNullValue_DoesntSetValue()
+        {
+            var parameters = new ParameterCollection();
+            parameters.AddOptionalBoolString("test", null);
+            Assert.That(parameters.ContainsKey("test"), Is.False);
+        }
+    }
+}
diff --git a/CryptoExchange.Net.UnitTests/UriSerializationTests.cs b/CryptoExchange.Net.UnitTests/UriSerializationTests.cs
new file mode 100644
index 0000000..8ff70d4
--- /dev/null
+++ b/CryptoExchange.Net.UnitTests/UriSerializationTests.cs
@@ -0,0 +1,105 @@
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using CryptoExchange.Net;
+using CryptoExchange.Net.Objects;
+
+namespace CryptoExchange.Net.UnitTests
+{
+    internal class UriSerializationTests
+    {
+        [Test]
+        public void CreateParamString_SerializesBasicValuesCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", "1" },
+                { "b", 2 },
+                { "c", true }
+            };
+
+            var parameterString = parameters.CreateParamString(false, ArrayParametersSerialization.Array);
+
+            Assert.That(parameterString, Is.EqualTo("a=1&b=2&c=True"));
+        }
+
+        [Test]
+        public void CreateParamString_SerializesArrayValuesCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", new [] { "1", "2" } },
+            };
+
+            var parameterString = parameters.CreateParamString(false, ArrayParametersSerialization.Array);
+
+            Assert.That(parameterString, Is.EqualTo("a[]=1&a[]=2"));
+        }
+
+        [Test]
+        public void CreateParamStringEncoded_SerializesArrayValuesCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", new [] { "1+2", "2+3" } },
+            };
+
+            var parameterString = parameters.CreateParamString(true, ArrayParametersSerialization.Array);
+
+            Assert.That(parameterString, Is.EqualTo("a[]=1%2B2&a[]=2%2B3"));
+        }
+
+        [Test]
+        public void CreateParamString_SerializesJsonArrayValuesCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", new [] { "1", "2" } },
+            };
+
+            var parameterString = parameters.CreateParamString(false, ArrayParametersSerialization.JsonArray);
+
+            Assert.That(parameterString, Is.EqualTo("a=[1,2]"));
+        }
+
+        [Test]
+        public void CreateParamStringEncoded_SerializesJsonArrayValuesCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", new [] { "1+2", "2+3" } },
+            };
+
+            var parameterString = parameters.CreateParamString(true, ArrayParametersSerialization.JsonArray);
+
+            Assert.That(parameterString, Is.EqualTo("a=[1%2B2,2%2B3]"));
+        }
+
+        [Test]
+        public void CreateParamString_SerializesMultipleValuesArrayCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", new [] { "1", "2" } },
+            };
+
+            var parameterString = parameters.CreateParamString(false, ArrayParametersSerialization.MultipleValues);
+
+            Assert.That(parameterString, Is.EqualTo("a=1&a=2"));
+        }
+
+        [Test]
+        public void CreateParamStringEncoded_SerializesMultipleValuesArrayCorrectly()
+        {
+            var parameters = new Dictionary<string, object>()
+            {
+                { "a", new [] { "1+2", "2+3" } },
+            };
+
+            var parameterString = parameters.CreateParamString(true, ArrayParametersSerialization.MultipleValues);
+
+            Assert.That(parameterString, Is.EqualTo("a=1%2B2&a=2%2B3"));
+        }
+    }
+}
diff --git a/CryptoExchange.Net/ExtensionMethods.cs b/CryptoExchange.Net/ExtensionMethods.cs
index c8d1693..452dce8 100644
--- a/CryptoExchange.Net/ExtensionMethods.cs
+++ b/CryptoExchange.Net/ExtensionMethods.cs
@@ -107,7 +107,7 @@ namespace CryptoExchange.Net
                     }
                     else
                     {
-                        uriString.Append('[');
+                        uriString.Append($"{parameter.Key}=[");
                         var firstArrayEntry = true;
                         foreach (var entry in (Array)parameter.Value)
                         {
diff --git a/CryptoExchange.Net/Objects/ParameterCollection.cs b/CryptoExchange.Net/Objects/ParameterCollection.cs
index d49f8fa..723fb6f 100644
--- a/CryptoExchange.Net/Objects/ParameterCollection.cs
+++ b/CryptoExchange.Net/Objects/ParameterCollection.cs
@@ -278,6 +278,35 @@ namespace CryptoExchange.Net.Objects
             base.Add(key, string.Join(",", values));
         }
 
+        /// <summary>
+        /// Add key as comma separated values
+        /// </summary>
+#if NET5_0_OR_GREATER
+        public void AddCommaSeparated<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor | DynamicallyAccessedMemberTypes.PublicFields)] T>(string key, IEnumerable<T> values)
+#else
+        public void AddCommaSeparated<T>(string key, IEnumerable<T> values)
+#endif
+            where T : struct, Enum
+        {
+            base.Add(key, string.Join(",", values.Select(x => EnumConverter.GetString(x))));
+        }
+
+        /// <summary>
+        /// Add key as comma separated values if there are values provided
+        /// </summary>
+#if NET5_0_OR_GREATER
+        public void AddOptionalCommaSeparated<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicParameterlessConstructor | DynamicallyAccessedMemberTypes.PublicFields)] T>(string key, IEnumerable<T>? values)
+#else
+        public void AddOptionalCommaSeparated<T>(string key, IEnumerable<T>? values)
+#endif
+            where T : struct, Enum
+        {
+            if (values == null || !values.Any())
+                return;
+
+            base.Add(key, string.Join(",", values.Select(x => EnumConverter.GetString(x))));
+        }
+
         /// <summary>
         /// Add key as boolean lower case value
         /// </summary>