diff --git a/Build/MQTTnet.nuspec b/Build/MQTTnet.nuspec
index fbf0bdc..3b7b0bf 100644
--- a/Build/MQTTnet.nuspec
+++ b/Build/MQTTnet.nuspec
@@ -37,6 +37,12 @@
         <dependency id="System.Net.WebSockets" version="4.3.0" />
         <dependency id="System.Net.WebSockets.Client" version="4.3.2" />
       </group>
+      <group targetFramework="netcoreapp3.1">
+        <dependency id="NETStandard.Library" version="2.0.0" />
+        <dependency id="System.Net.Security" version="4.3.2" />
+        <dependency id="System.Net.WebSockets" version="4.3.0" />
+        <dependency id="System.Net.WebSockets.Client" version="4.3.2" />
+      </group>
       <group targetFramework="uap10.0">
         <dependency id="Microsoft.NETCore.UniversalWindowsPlatform" version="6.2.10" />
       </group>
@@ -59,6 +65,9 @@
     <!-- .NET Standard 2.1 -->
     <file src="..\Source\MQTTnet\bin\Release\netstandard2.1\MQTTnet.*" target="lib\netstandard2.1\"/>
 
+    <!-- .NET Standard 3.1 -->
+    <file src="..\Source\MQTTnet\bin\Release\netcoreapp3.1\MQTTnet.*" target="lib\netcoreapp3.1\"/>
+
     <!-- Universal Windows -->
     <file src="..\Source\MQTTnet\bin\Release\uap10.0\MQTTnet.*" target="lib\uap10.0\"/>
 
diff --git a/Build/build.ps1 b/Build/build.ps1
index b867ff6..7d68da5 100644
--- a/Build/build.ps1
+++ b/Build/build.ps1
@@ -29,6 +29,7 @@ vstest.console.exe ..\Tests\MQTTnet.AspNetCore.Tests\bin\Release\netcoreapp3.1\M
 &$msbuild ..\Source\MQTTnet\MQTTnet.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard1.3" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
 &$msbuild ..\Source\MQTTnet\MQTTnet.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
 &$msbuild ..\Source\MQTTnet\MQTTnet.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netstandard2.1" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
+&$msbuild ..\Source\MQTTnet\MQTTnet.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="netcoreapp3.1" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
 &$msbuild ..\Source\MQTTnet\MQTTnet.csproj /t:Build /p:Configuration="Release" /p:TargetFramework="uap10.0" /p:FileVersion=$assemblyVersion /p:AssemblyVersion=$assemblyVersion /verbosity:m /p:SignAssembly=true /p:AssemblyOriginatorKeyFile=".\..\..\Build\codeSigningKey.pfx"
 
 # Build the ASP.NET Core 2.0 extension
diff --git a/Source/MQTTnet.AspnetCore/MQTTnet.AspNetCore.csproj b/Source/MQTTnet.AspnetCore/MQTTnet.AspNetCore.csproj
index 3c9cd22..dc44208 100644
--- a/Source/MQTTnet.AspnetCore/MQTTnet.AspNetCore.csproj
+++ b/Source/MQTTnet.AspnetCore/MQTTnet.AspNetCore.csproj
@@ -27,6 +27,7 @@
     
   <ItemGroup Condition="'$(TargetFramework)' != 'netcoreapp3.1'">
     <PackageReference Include="Microsoft.AspNetCore.Http.Connections" Version="1.1.0" />
+    <PackageReference Include="System.IO.Pipelines" Version="4.7.2" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/Source/MQTTnet/Client/Options/MqttClientOptionsBuilder.cs b/Source/MQTTnet/Client/Options/MqttClientOptionsBuilder.cs
index dcd5d34..e3a3afe 100644
--- a/Source/MQTTnet/Client/Options/MqttClientOptionsBuilder.cs
+++ b/Source/MQTTnet/Client/Options/MqttClientOptionsBuilder.cs
@@ -280,7 +280,9 @@ namespace MQTTnet.Client.Options
 #pragma warning disable CS0618 // Type or member is obsolete
                         CertificateValidationCallback = _tlsParameters.CertificateValidationCallback,
 #pragma warning restore CS0618 // Type or member is obsolete
-
+#if NETCOREAPP3_1
+	                    ApplicationProtocols = _tlsParameters.ApplicationProtocols,
+#endif
                         CertificateValidationHandler = _tlsParameters.CertificateValidationHandler,
                         IgnoreCertificateChainErrors = _tlsParameters.IgnoreCertificateChainErrors,
                         IgnoreCertificateRevocationErrors = _tlsParameters.IgnoreCertificateRevocationErrors
diff --git a/Source/MQTTnet/Client/Options/MqttClientOptionsBuilderTlsParameters.cs b/Source/MQTTnet/Client/Options/MqttClientOptionsBuilderTlsParameters.cs
index fd9aad0..6f214eb 100644
--- a/Source/MQTTnet/Client/Options/MqttClientOptionsBuilderTlsParameters.cs
+++ b/Source/MQTTnet/Client/Options/MqttClientOptionsBuilderTlsParameters.cs
@@ -27,7 +27,11 @@ namespace MQTTnet.Client.Options
         public IEnumerable<X509Certificate> Certificates { get; set; }
 #endif
 
-        public bool AllowUntrustedCertificates { get; set; }
+#if NETCOREAPP3_1
+	    public List<SslApplicationProtocol> ApplicationProtocols { get;set; }
+#endif 
+
+	    public bool AllowUntrustedCertificates { get; set; }
 
         public bool IgnoreCertificateChainErrors { get; set; }
 
diff --git a/Source/MQTTnet/Client/Options/MqttClientTlsOptions.cs b/Source/MQTTnet/Client/Options/MqttClientTlsOptions.cs
index b1b3fe8..1675ded 100644
--- a/Source/MQTTnet/Client/Options/MqttClientTlsOptions.cs
+++ b/Source/MQTTnet/Client/Options/MqttClientTlsOptions.cs
@@ -22,6 +22,10 @@ namespace MQTTnet.Client.Options
         public List<X509Certificate> Certificates { get; set; }
 #endif
 
+#if NETCOREAPP3_1
+		public List<SslApplicationProtocol> ApplicationProtocols {get;set;}
+#endif
+
         public SslProtocols SslProtocol { get; set; } = SslProtocols.Tls12;
 
         [Obsolete("This property will be removed soon. Use CertificateValidationHandler instead.")]
diff --git a/Source/MQTTnet/Diagnostics/TargetFrameworkProvider.cs b/Source/MQTTnet/Diagnostics/TargetFrameworkProvider.cs
index ea408ca..82d133e 100644
--- a/Source/MQTTnet/Diagnostics/TargetFrameworkProvider.cs
+++ b/Source/MQTTnet/Diagnostics/TargetFrameworkProvider.cs
@@ -20,6 +20,8 @@
                 return "netstandard2.1";
 #elif WINDOWS_UWP
                 return "uap10.0";
+#elif NETCOREAPP3_1
+                return "netcoreapp3.1";
 #endif
             }
         }
diff --git a/Source/MQTTnet/Implementations/MqttTcpChannel.cs b/Source/MQTTnet/Implementations/MqttTcpChannel.cs
index 72c0e00..312d704 100644
--- a/Source/MQTTnet/Implementations/MqttTcpChannel.cs
+++ b/Source/MQTTnet/Implementations/MqttTcpChannel.cs
@@ -81,7 +81,22 @@ namespace MQTTnet.Implementations
                     var sslStream = new SslStream(networkStream, false, InternalUserCertificateValidationCallback);
                     try
                     {
-                        await sslStream.AuthenticateAsClientAsync(_options.Server, LoadCertificates(), _options.TlsOptions.SslProtocol, !_options.TlsOptions.IgnoreCertificateRevocationErrors).ConfigureAwait(false);
+                        
+#if NETCOREAPP3_1
+	                    var sslOptions = new SslClientAuthenticationOptions
+	                    {
+		                    ApplicationProtocols = _options.TlsOptions.ApplicationProtocols,
+		                    ClientCertificates = LoadCertificates(),
+		                    EnabledSslProtocols = _options.TlsOptions.SslProtocol,
+		                    CertificateRevocationCheckMode = _options.TlsOptions.IgnoreCertificateRevocationErrors ? X509RevocationMode.Online : X509RevocationMode.NoCheck,
+		                    TargetHost = _options.Server
+	                    };
+	                    await sslStream.AuthenticateAsClientAsync(sslOptions, cancellationToken).ConfigureAwait(false);
+#else 
+                        
+                        
+	                    await sslStream.AuthenticateAsClientAsync(_options.Server, LoadCertificates(), _options.TlsOptions.SslProtocol, !_options.TlsOptions.IgnoreCertificateRevocationErrors).ConfigureAwait(false);
+#endif
                     }
                     catch
                     {
diff --git a/Source/MQTTnet/MQTTnet.csproj b/Source/MQTTnet/MQTTnet.csproj
index eddb941..66b39fa 100644
--- a/Source/MQTTnet/MQTTnet.csproj
+++ b/Source/MQTTnet/MQTTnet.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard1.3;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>netstandard1.3;netstandard2.0;netstandard2.1;netcoreapp3.1</TargetFrameworks>
     <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' ">$(TargetFrameworks);net452;net461</TargetFrameworks>
     <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' AND '$(MSBuildRuntimeType)' != 'Core' AND '$(SolutionName)' != 'MQTTnet.noUWP' ">$(TargetFrameworks);uap10.0</TargetFrameworks>
     <AssemblyName>MQTTnet</AssemblyName>