diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7f6f11f..6223ec8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+## [4.0.0] - 2023-11-07
+- Update RestSharp to version 108.0.3
+- Update Newtonsoft.Json to version 13.0.3
+- Update target framework to netstandard2.0, and remove net452 as a target framework
+
 ## [3.3.2] - 2021-10-20
 - Update RestSharp to version 106.12.0
 
@@ -100,7 +105,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## [1.0.0] - 2016-09-20
 - Initial release
 
-[Unreleased]: https://github.com/taxjar/taxjar.net/compare/v3.3.2...HEAD
+[Unreleased]: https://github.com/taxjar/taxjar.net/compare/v4.0.0...HEAD
+[4.0.0]: https://github.com/taxjar/taxjar.net/compare/v3.3.2...v4.0.0
 [3.3.2]: https://github.com/taxjar/taxjar.net/compare/v3.3.1...v3.3.2
 [3.3.1]: https://github.com/taxjar/taxjar.net/compare/v3.3.0...v3.3.1
 [3.3.0]: https://github.com/taxjar/taxjar.net/compare/v3.2.1...v3.3.0
diff --git a/README.md b/README.md
index 28f365d..b1591fc 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ PM> Install-Package TaxJar
 
 ## Package Dependencies
 
-TaxJar.net comes with assemblies for **.NET 4.5.2** and **.NET Standard 2.0**. It requires the following dependencies:
+TaxJar.net comes with assemblies for **.NET Standard 2.0**. It requires the following dependencies:
 
 - [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json) Popular high-performance JSON framework for .NET
 - [RestSharp](https://github.com/restsharp/RestSharp) Simple REST and HTTP API Client for .NET
diff --git a/build/TaxJar.nuspec b/build/TaxJar.nuspec
index fb8c13a..66d24c1 100644
--- a/build/TaxJar.nuspec
+++ b/build/TaxJar.nuspec
@@ -3,7 +3,7 @@
   <metadata xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
     <id>TaxJar</id>
     <title>TaxJar</title>
-    <version>3.3.2</version>
+    <version>4.0.0</version>
     <authors>Jake Johnson</authors>
     <owners>TaxJar</owners>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
@@ -12,20 +12,21 @@
     <iconUrl>https://github.com/taxjar/taxjar.net/raw/master/build/taxjar-icon.png</iconUrl>
     <description>TaxJar makes sales tax filing easier for online sellers and merchants. See local jurisdictional tax reports, get payment reminders, and more. You can use our API to access TaxJar API endpoints, which can get information on sales tax rates, categories or upload transactions.</description>
     <releaseNotes>
-- Update RestSharp to version 106.12.0
+- Update RestSharp to 108.0.3
+- Update Newtonsoft.Json to 13.0.3
+- Update target framework to netstandard2.0 (remove net452)
     </releaseNotes>
     <language>en-US</language>
     <tags>sales tax taxes ecommerce</tags>
     <copyright>Copyright (c) 2019 TaxJar</copyright>
     <dependencies>
       <group>
-        <dependency id="Newtonsoft.Json" version="12.0.3" />
-        <dependency id="RestSharp" version="[106.12.0,107.0.0)" />
+        <dependency id="Newtonsoft.Json" version="13.0.3" />
+        <dependency id="RestSharp" version="108.0.3" />
       </group>
     </dependencies>
   </metadata>
   <files>
-    <file src="net452/TaxJar.dll" target="lib/net452" />
     <file src="netstandard2.0/TaxJar.dll" target="lib/netstandard2.0" />
   </files>
 </package>
diff --git a/src/Taxjar.Tests/TaxJar.Tests.csproj b/src/Taxjar.Tests/TaxJar.Tests.csproj
index 527680e..67d5b62 100644
--- a/src/Taxjar.Tests/TaxJar.Tests.csproj
+++ b/src/Taxjar.Tests/TaxJar.Tests.csproj
@@ -6,7 +6,7 @@
     <AssemblyName>TaxJar.Tests</AssemblyName>
     <IsPackable>false</IsPackable>
     <SignAssembly>true</SignAssembly>
-    <ReleaseVersion>3.3.2</ReleaseVersion>
+    <ReleaseVersion>4.0.0</ReleaseVersion>
     <OutputType>Library</OutputType>
   </PropertyGroup>
 
diff --git a/src/Taxjar.sln b/src/Taxjar.sln
index 4fdb16a..0bf8396 100644
--- a/src/Taxjar.sln
+++ b/src/Taxjar.sln
@@ -1,52 +1,52 @@
-
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 2012
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TaxJar", "TaxJar\TaxJar.csproj", "{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}"
-EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TaxJar.Tests", "TaxJar.Tests\TaxJar.Tests.csproj", "{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}"
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|Any CPU = Debug|Any CPU
-		Release|Any CPU = Release|Any CPU
-		Debug|x86 = Debug|x86
-		Release|x86 = Release|x86
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|x86.Build.0 = Debug|Any CPU
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|Any CPU.Build.0 = Release|Any CPU
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|x86.ActiveCfg = Release|Any CPU
-		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|x86.Build.0 = Release|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|Any CPU.Build.0 = Release|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|x86.Build.0 = Debug|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|x86.ActiveCfg = Release|Any CPU
-		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|x86.Build.0 = Release|Any CPU
-	EndGlobalSection
-	GlobalSection(MonoDevelopProperties) = preSolution
-		Policies = $0
-		$0.DotNetNamingPolicy = $1
-		$0.StandardHeader = $2
-		$0.NameConventionPolicy = $3
-		$3.Rules = $4
-		$4.NamingRule = $5
-		$5.Name = Type Parameters
-		$5.AffectedEntity = TypeParameter
-		$5.VisibilityMask = VisibilityMask
-		$5.NamingStyle = PascalCase
-		$5.IncludeInstanceMembers = True
-		$5.IncludeStaticEntities = True
-		$5.RequiredPrefixes = $6
-		$6.String = T
-		$5.RequiredSuffixes = $7
-		$7.String = Exception
-		version = 3.3.2
-	EndGlobalSection
-EndGlobal
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 2012
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TaxJar", "TaxJar\TaxJar.csproj", "{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TaxJar.Tests", "TaxJar.Tests\TaxJar.Tests.csproj", "{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+		Debug|x86 = Debug|x86
+		Release|x86 = Release|x86
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Debug|x86.Build.0 = Debug|Any CPU
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|x86.ActiveCfg = Release|Any CPU
+		{CE4FFA2A-801C-488A-BF28-0EAAB8877C2D}.Release|x86.Build.0 = Release|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|Any CPU.Build.0 = Release|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Debug|x86.Build.0 = Debug|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|x86.ActiveCfg = Release|Any CPU
+		{34AC1F7E-13AD-4EE2-8B1E-2AB71C85C246}.Release|x86.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(MonoDevelopProperties) = preSolution
+		Policies = $0
+		$0.DotNetNamingPolicy = $1
+		$0.StandardHeader = $2
+		$0.NameConventionPolicy = $3
+		$3.Rules = $4
+		$4.NamingRule = $5
+		$5.Name = Type Parameters
+		$5.AffectedEntity = TypeParameter
+		$5.VisibilityMask = VisibilityMask
+		$5.NamingStyle = PascalCase
+		$5.IncludeInstanceMembers = True
+		$5.IncludeStaticEntities = True
+		$5.RequiredPrefixes = $6
+		$6.String = T
+		$5.RequiredSuffixes = $7
+		$7.String = Exception
+		version = 4.0.0
+	EndGlobalSection
+EndGlobal
diff --git a/src/Taxjar/Taxjar.csproj b/src/Taxjar/Taxjar.csproj
index 25e8b3d..1a184fa 100644
--- a/src/Taxjar/Taxjar.csproj
+++ b/src/Taxjar/Taxjar.csproj
@@ -4,7 +4,7 @@
     <TargetFramework>netstandard2.0</TargetFramework>
     <Description>TaxJar makes sales tax filing easier for online sellers and merchants. See local jurisdictional tax reports, get payment reminders, and more. You can use our API to access TaxJar API endpoints, which can get information on sales tax rates, categories or upload transactions.</Description>
     <AssemblyTitle>TaxJar</AssemblyTitle>
-    <Version>3.3.2</Version>
+    <Version>4.0.0</Version>
     <Authors>Jake Johnson</Authors>
     <AssemblyName>TaxJar</AssemblyName>
     <PackageId>TaxJar</PackageId>
@@ -12,7 +12,7 @@
     <RootNamespace>Taxjar</RootNamespace>
     <PackageProjectUrl>https://github.com/taxjar/taxjar.net</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/taxjar/taxjar.net/blob/master/LICENSE.txt</PackageLicenseUrl>
-    <ReleaseVersion>3.3.2</ReleaseVersion>
+    <ReleaseVersion>4.0.0</ReleaseVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">