diff --git a/AMWD.Protocols.Modbus.Common/Contracts/ModbusClientBase.cs b/AMWD.Protocols.Modbus.Common/Contracts/ModbusClientBase.cs
index d00c99b..5a59f3d 100644
--- a/AMWD.Protocols.Modbus.Common/Contracts/ModbusClientBase.cs
+++ b/AMWD.Protocols.Modbus.Common/Contracts/ModbusClientBase.cs
@@ -1,9 +1,9 @@
 using System;
 using System.Collections.Generic;
-using System.Threading.Tasks;
-using System.Threading;
 using System.Linq;
 using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace AMWD.Protocols.Modbus.Common.Contracts
 {
diff --git a/AMWD.Protocols.Modbus.Common/Exceptions/ModbusException.cs b/AMWD.Protocols.Modbus.Common/Exceptions/ModbusException.cs
index 377e9f2..87cfdad 100644
--- a/AMWD.Protocols.Modbus.Common/Exceptions/ModbusException.cs
+++ b/AMWD.Protocols.Modbus.Common/Exceptions/ModbusException.cs
@@ -1,6 +1,8 @@
 using System;
 using System.Diagnostics.CodeAnalysis;
+#if !NET8_0_OR_GREATER
 using System.Runtime.Serialization;
+#endif
 
 namespace AMWD.Protocols.Modbus.Common
 {
diff --git a/AMWD.Protocols.Modbus.Common/Models/ModbusObject.cs b/AMWD.Protocols.Modbus.Common/Models/ModbusObject.cs
index c7b91b0..a6e3b6b 100644
--- a/AMWD.Protocols.Modbus.Common/Models/ModbusObject.cs
+++ b/AMWD.Protocols.Modbus.Common/Models/ModbusObject.cs
@@ -1,4 +1,6 @@
-using System;
+#if NET6_0_OR_GREATER
+using System;
+#endif
 
 namespace AMWD.Protocols.Modbus.Common
 {
diff --git a/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs b/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs
index 72089b4..3815822 100644
--- a/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs
+++ b/AMWD.Protocols.Modbus.Common/Protocols/RtuOverTcpProtocol.cs
@@ -10,7 +10,9 @@ namespace AMWD.Protocols.Modbus.Common.Protocols
 	/// </summary>
 	/// <remarks>
 	/// The Modbus RTU over Modbus TCP is rarely used.
-	/// It is a non-standard variant of Modbus TCP that includes wrapps a Modbus RTU message within a Modbus TCP message.
+	/// It is a non-standard variant:
+	/// You can define it as RTU message with an additional TCP header
+	/// or as TCP message with an additional CRC16 checksum at the end (header not included!).
 	/// <br/>
 	/// Definition found on <see href="https://www.fernhillsoftware.com/help/drivers/modbus/modbus-protocol.html">Fernhill Software</see>.
 	/// </remarks>
diff --git a/AMWD.Protocols.Modbus.Proxy/ModbusTcpProxy.cs b/AMWD.Protocols.Modbus.Proxy/ModbusTcpProxy.cs
index 40987e0..ce1ef23 100644
--- a/AMWD.Protocols.Modbus.Proxy/ModbusTcpProxy.cs
+++ b/AMWD.Protocols.Modbus.Proxy/ModbusTcpProxy.cs
@@ -370,7 +370,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleReadDiscreteInputsAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -409,7 +409,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleReadHoldingRegistersAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -443,7 +443,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleReadInputRegistersAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -477,7 +477,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleWriteSingleCoilAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -494,7 +494,8 @@ namespace AMWD.Protocols.Modbus.Proxy
 			{
 				responseBytes[7] |= 0x80;
 				responseBytes.Add((byte)ModbusErrorCode.IllegalDataValue);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 
 			try
@@ -524,7 +525,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleWriteSingleRegisterAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -564,7 +565,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleWriteMultipleCoilsAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -583,7 +584,8 @@ namespace AMWD.Protocols.Modbus.Proxy
 			{
 				responseBytes[7] |= 0x80;
 				responseBytes.Add((byte)ModbusErrorCode.IllegalDataValue);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 
 			try
@@ -623,7 +625,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleWriteMultipleRegistersAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -642,7 +644,8 @@ namespace AMWD.Protocols.Modbus.Proxy
 			{
 				responseBytes[7] |= 0x80;
 				responseBytes.Add((byte)ModbusErrorCode.IllegalDataValue);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 
 			try
@@ -679,7 +682,7 @@ namespace AMWD.Protocols.Modbus.Proxy
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
 			}
 
-			return [.. responseBytes];
+			return ReturnResponse(responseBytes);
 		}
 
 		private async Task<byte[]> HandleEncapsulatedInterfaceAsync(byte[] requestBytes, CancellationToken cancellationToken)
@@ -691,7 +694,8 @@ namespace AMWD.Protocols.Modbus.Proxy
 			{
 				responseBytes[7] |= 0x80;
 				responseBytes.Add((byte)ModbusErrorCode.IllegalFunction);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 
 			var firstObject = (ModbusDeviceIdentificationObject)requestBytes[10];
@@ -699,7 +703,8 @@ namespace AMWD.Protocols.Modbus.Proxy
 			{
 				responseBytes[7] |= 0x80;
 				responseBytes.Add((byte)ModbusErrorCode.IllegalDataAddress);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 
 			var category = (ModbusDeviceIdentificationCategory)requestBytes[9];
@@ -707,7 +712,8 @@ namespace AMWD.Protocols.Modbus.Proxy
 			{
 				responseBytes[7] |= 0x80;
 				responseBytes.Add((byte)ModbusErrorCode.IllegalDataValue);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 
 			try
@@ -764,7 +770,8 @@ namespace AMWD.Protocols.Modbus.Proxy
 
 						bodyBytes[5] = numberOfObjects;
 						responseBytes.AddRange(bodyBytes);
-						return [.. responseBytes];
+
+						return ReturnResponse(responseBytes);
 					}
 
 					bodyBytes.AddRange(objBytes);
@@ -773,13 +780,15 @@ namespace AMWD.Protocols.Modbus.Proxy
 
 				bodyBytes[5] = numberOfObjects;
 				responseBytes.AddRange(bodyBytes);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 			catch
 			{
 				responseBytes[7] |= 0x80;
 				responseBytes.Add((byte)ModbusErrorCode.SlaveDeviceFailure);
-				return [.. responseBytes];
+
+				return ReturnResponse(responseBytes);
 			}
 		}
 
@@ -863,6 +872,16 @@ namespace AMWD.Protocols.Modbus.Proxy
 			return [.. result];
 		}
 
+		private static byte[] ReturnResponse(List<byte> response)
+		{
+			ushort followingBytes = (ushort)(response.Count - 6);
+			byte[] bytes = followingBytes.ToBigEndianBytes();
+			response[4] = bytes[0];
+			response[5] = bytes[1];
+
+			return [.. response];
+		}
+
 		#endregion Request Handling
 	}
 }
diff --git a/AMWD.Protocols.Modbus.Serial/ModbusSerialConnection.cs b/AMWD.Protocols.Modbus.Serial/ModbusSerialConnection.cs
index 8d54951..94cc1fa 100644
--- a/AMWD.Protocols.Modbus.Serial/ModbusSerialConnection.cs
+++ b/AMWD.Protocols.Modbus.Serial/ModbusSerialConnection.cs
@@ -107,9 +107,7 @@ namespace AMWD.Protocols.Modbus.Serial
 			set => _serialPort.PortName = value;
 		}
 
-		/// <summary>
-		/// Gets or sets the serial baud rate.
-		/// </summary>
+		/// <inheritdoc cref="SerialPort.BaudRate" />
 		public virtual BaudRate BaudRate
 		{
 			get => (BaudRate)_serialPort.BaudRate;
@@ -118,7 +116,11 @@ namespace AMWD.Protocols.Modbus.Serial
 
 		/// <inheritdoc cref="SerialPort.DataBits" />
 		/// <remarks>
-		/// Should be 7 for ASCII mode and 8 for RTU mode.
+		/// From the Specs:
+		/// <br/>
+		/// On <see cref="AsciiProtocol"/> it can be 7 or 8.
+		/// <br/>
+		/// On <see cref="RtuProtocol"/> it has to be 8.
 		/// </remarks>
 		public virtual int DataBits
 		{
@@ -159,9 +161,9 @@ namespace AMWD.Protocols.Modbus.Serial
 		/// <remarks>
 		/// From the Specs:
 		/// <br/>
-		/// Should be <see cref="StopBits.One"/> for <see cref="Parity.Even"/> or <see cref="Parity.Odd"/> and
+		/// Should be <see cref="StopBits.One"/> for <see cref="Parity.Even"/> or <see cref="Parity.Odd"/>.
 		/// <br/>
-		/// should be <see cref="StopBits.Two"/> for <see cref="Parity.None"/>.
+		/// Should be <see cref="StopBits.Two"/> for <see cref="Parity.None"/>.
 		/// </remarks>
 		public virtual StopBits StopBits
 		{
@@ -188,7 +190,6 @@ namespace AMWD.Protocols.Modbus.Serial
 
 			try
 			{
-				_processingTask.Wait();
 				_processingTask.Dispose();
 			}
 			catch
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 006455c..ede9233 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - The `ModbusTcpProxy.ReadWriteTimeout` has a default value of 100 seconds (same default as a `HttpClient` has).
 
+### Fixed
+
+- Wrong _following bytes_ calculation in `ModbusTcpProxy`.
+
 
 ## [v0.3.2] (2024-09-04)