Restore old properties to avoid breaking changes

Source/MQTTnet/Client/Options/MqttClientOptionsBuilder.cs

@@ -376,20 +376,9 @@ public MqttClientOptionsBuilder WithTcpServer(string host, int? port = null, Add
 
             _tcpOptions = new MqttClientTcpOptions();
 
-            _port = port;
-
             // The value 0 will be updated when building the options.
             // This a backward compatibility feature.
-
-            if (IPAddress.TryParse(host, out var ipAddress))
-            {
-                _remoteEndPoint = new IPEndPoint(ipAddress, port ?? 0);
-            }
-            else
-            {
-                _remoteEndPoint = new DnsEndPoint(host, port ?? 0, addressFamily);
-            }
-
+            _remoteEndPoint = new DnsEndPoint(host, port ?? 0, addressFamily);
             _port = port;
 
             return this;

Source/MQTTnet/Client/Options/MqttClientTcpOptions.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.Net;
 using System.Net.Sockets;
 
@@ -20,6 +21,12 @@ public sealed class MqttClientTcpOptions : IMqttClientChannelOptions
         /// </summary>
         public bool? DualMode { get; set; }
 
+        [Obsolete("Use RemoteEndpoint or MqttClientOptionsBuilder instead.")]
+        public int? Port { get; set; }
+
+        [Obsolete("Use RemoteEndpoint or MqttClientOptionsBuilder instead.")]
+        public string Server { get; set; }
+
         public LingerOption LingerState { get; set; } = new LingerOption(true, 0);
 
         /// <summary>

Source/MQTTnet/Implementations/MqttTcpChannel.cs

@@ -16,6 +16,7 @@
 using MQTTnet.Client;
 using MQTTnet.Exceptions;
 using MQTTnet.Internal;
+using MQTTnet.Protocol;
 
 namespace MQTTnet.Implementations
 {
@@ -98,6 +99,29 @@ public async Task ConnectAsync(CancellationToken cancellationToken)
                     socket.DualMode = _tcpOptions.DualMode.Value;
                 }
 
+                // This block is only for backward compatibility.
+                if (_tcpOptions.RemoteEndpoint == null && !string.IsNullOrEmpty(_tcpOptions.Server))
+                {
+                    int port;
+                    if (_tcpOptions.Port.HasValue)
+                    {
+                        port = _tcpOptions.Port.Value;
+                    }
+                    else
+                    {
+                        if (_tcpOptions.TlsOptions?.UseTls == true)
+                        {
+                            port = MqttPorts.Secure;
+                        }
+                        else
+                        {
+                            port = MqttPorts.Default;
+                        }
+                    }
+
+                    _tcpOptions.RemoteEndpoint = new DnsEndPoint(_tcpOptions.Server, port, AddressFamily.Unspecified);
+                }
+
                 await socket.ConnectAsync(_tcpOptions.RemoteEndpoint, cancellationToken).ConfigureAwait(false);
 
                 cancellationToken.ThrowIfCancellationRequested();