diff --git a/src/Twilio/Http/SystemNetHttpClient.cs b/src/Twilio/Http/SystemNetHttpClient.cs
index 29762072f..117466f2d 100644
--- a/src/Twilio/Http/SystemNetHttpClient.cs
+++ b/src/Twilio/Http/SystemNetHttpClient.cs
@@ -15,8 +15,8 @@ namespace Twilio.Http
     /// </summary>
     public class SystemNetHttpClient : HttpClient
     {
-#if NET451
-        private string PlatVersion = ".NET Framework 4.5.1+";
+#if NET462
+        private string PlatVersion = ".NET Framework 4.6.2+";
 #else
         private string PlatVersion = RuntimeInformation.FrameworkDescription;
 #endif
@@ -125,7 +125,7 @@ private HttpRequestMessage BuildHttpRequest(Request request)
 #endif
 
             string osArch;
-#if !NET451
+#if !NET462
             osArch = RuntimeInformation.OSArchitecture.ToString();
 #else
             osArch = Environment.GetEnvironmentVariable("PROCESSOR_ARCHITECTURE") ?? "Unknown"; 
diff --git a/src/Twilio/Twilio.csproj b/src/Twilio/Twilio.csproj
index 10dd28869..9f03494a6 100644
--- a/src/Twilio/Twilio.csproj
+++ b/src/Twilio/Twilio.csproj
@@ -1,8 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup Label="NuGet">
-    <TargetFramework>net6.0</TargetFramework>
-    <OutputPath>bin/Release</OutputPath>
-    <Nullable>enable</Nullable>
+    <TargetFrameworks>net6.0;netstandard2.1;net462;net35</TargetFrameworks>
     <IsPackable>true</IsPackable>
     <PackageId>Twilio</PackageId>
     <Description>Twilio REST API helper library</Description>
@@ -24,12 +22,40 @@
     <RepositoryUrl>http://github.com/twilio/twilio-csharp</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
+    <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard2.1' ">2.1.0</NetStandardImplicitPackageVersion>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.IdentityModel.JsonWebTokens" Version="6.15.0" />
+    <Reference Include="System.Xml.Linq" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+  </ItemGroup>
+  <ItemGroup Condition=" '$(TargetFramework)' == 'net6.0' ">
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+    <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="6.15.0" />
+    <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.19.0" />
+    <PackageReference Include="System.Collections.Specialized" Version="4.3.0" />
+  </ItemGroup>
+  <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.1' ">
     <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
-    <PackageReference Include="NUnit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
     <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="6.15.0" />
+    <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.19.0" />
+    <PackageReference Include="System.Collections.Specialized" Version="4.3.0" />
+  </ItemGroup>
+  <ItemGroup Condition=" '$(TargetFramework)' == 'net35' ">
+    <Reference Include="System" />
+    <Reference Include="System.Web" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+    <PackageReference Include="JWT" Version="1.3.4" />
+  </ItemGroup>
+  <ItemGroup Condition=" '$(TargetFramework)' == 'net462' ">
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
+    <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="6.15.0" />
+    <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="6.19.0" />
+    <PackageReference Include="System.Collections.Specialized" Version="4.3.0" />
+    <Reference Include="System.Net" />
+    <Reference Include="System.Net.Http" />
+  </ItemGroup>
+  <ItemGroup Condition="($(TargetFramework.StartsWith('net3')) OR $(TargetFramework.StartsWith('net4'))) AND '$(MSBuildRuntimeType)' == 'Core' AND '$(OS)' != 'Windows_NT'">
+    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0" PrivateAssets="All" />
+    <PackageReference Include="jnm2.ReferenceAssemblies.net35" Version="1.0.1" PrivateAssets="All" />
   </ItemGroup>
 </Project>
\ No newline at end of file