diff --git a/.github/workflows/ReleaseNotes.md b/.github/workflows/ReleaseNotes.md
index 5ee275ee8..069f272e4 100644
--- a/.github/workflows/ReleaseNotes.md
+++ b/.github/workflows/ReleaseNotes.md
@@ -1,4 +1,5 @@
 * [Client] Fixed _PlatformNotSupportedException_ when using Blazor (#1755, thanks to @Nickztar).
+* [Client] Added support for _RemoteCertificateValidationCallback_ for .NET 4.5.2, 4.6.1 and 4.8 (#1806, thanks to @troky).
 * [Client] Fixed wrong logging of obsolete feature when connection was not successful (#1801, thanks to @ramonsmits).
 * [Client] Fixed _NullReferenceException_ when performing several actions when not connected (#1800, thanks to @ramonsmits).
 * [Server] Fixed _NullReferenceException_ in retained messages management (#1762, thanks to @logicaloud).
diff --git a/Source/MQTTnet/Client/Options/MqttClientCertificateValidationEventArgs.cs b/Source/MQTTnet/Client/Options/MqttClientCertificateValidationEventArgs.cs
index f1842cb1e..ff4825612 100644
--- a/Source/MQTTnet/Client/Options/MqttClientCertificateValidationEventArgs.cs
+++ b/Source/MQTTnet/Client/Options/MqttClientCertificateValidationEventArgs.cs
@@ -14,8 +14,14 @@ public sealed class MqttClientCertificateValidationEventArgs : EventArgs
 
         public X509Chain Chain { get; set; }
 
-        public SslPolicyErrors SslPolicyErrors { get; set; }
-
         public IMqttClientChannelOptions ClientOptions { get; set; }
+#if NET452 || NET461 || NET48
+        /// <summary>
+        ///     Can be a host string name or an object derived from WebRequest.
+        /// </summary>
+        public object Sender { get; set; }
+#endif
+
+        public SslPolicyErrors SslPolicyErrors { get; set; }
     }
-}
+}
\ No newline at end of file
diff --git a/Source/MQTTnet/Implementations/MqttWebSocketChannel.cs b/Source/MQTTnet/Implementations/MqttWebSocketChannel.cs
index fd4027a92..be31c2a51 100644
--- a/Source/MQTTnet/Implementations/MqttWebSocketChannel.cs
+++ b/Source/MQTTnet/Implementations/MqttWebSocketChannel.cs
@@ -248,12 +248,20 @@ void SetupClientWebSocket(ClientWebSocket clientWebSocket)
                 throw new NotSupportedException("Remote certificate validation callback is not supported when using 'netstandard2.0'.");
 #elif WINDOWS_UWP
                 throw new NotSupportedException("Remote certificate validation callback is not supported when using 'uap10.0'.");
-#elif NET452
-                throw new NotSupportedException("Remote certificate validation callback is not supported when using 'net452'.");
-#elif NET461
-                throw new NotSupportedException("Remote certificate validation callback is not supported when using 'net461'.");
-#elif NET48
-                throw new NotSupportedException("Remote certificate validation callback is not supported when using 'net48'.");
+#elif NET452 || NET461 || NET48
+                ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => 
+                {
+                    var context = new MqttClientCertificateValidationEventArgs
+                    {
+                        Sender = sender,
+                        Certificate = certificate,
+                        Chain = chain,
+                        SslPolicyErrors = sslPolicyErrors,
+                        ClientOptions = _options
+                    };
+
+                    return certificateValidationHandler(context);
+                };
 #else
                 clientWebSocket.Options.RemoteCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) =>
                 {
@@ -272,4 +280,4 @@ void SetupClientWebSocket(ClientWebSocket clientWebSocket)
             }
         }
     }
-}
\ No newline at end of file
+}