diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 8bd164487..6c731c1b0 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -19,10 +19,6 @@ jobs:
     - uses: actions/checkout@v4
       with:
         submodules: true
-    - name: Setup .NET Core 3.1
-      uses: actions/setup-dotnet@v4
-      with:
-        dotnet-version: '3.1.x'
     - name: Setup .NET 6.0
       uses: actions/setup-dotnet@v4
       with:
@@ -31,6 +27,10 @@ jobs:
       uses: actions/setup-dotnet@v4
       with:
         dotnet-version: '8.0.x'
+    - name: Setup .NET 9.0
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '9.0.x'
     - name: Version Information
       run: |
         dotnet --info
@@ -48,9 +48,6 @@ jobs:
     - name: Test (net462)
       run: ./make.ps1 -frameworks net462 test-all
       shell: pwsh
-    - name: Test (netcoreapp3.1)
-      run: ./make.ps1 -frameworks netcoreapp3.1 test-all
-      shell: pwsh
     - name: Test (net6.0)
       run: ./make.ps1 -frameworks net6.0 test-all
       shell: pwsh
diff --git a/Build/netcoreapp3.1.props b/Build/netcoreapp3.1.props
deleted file mode 100644
index 53b1e59f1..000000000
--- a/Build/netcoreapp3.1.props
+++ /dev/null
@@ -1,38 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <PropertyGroup>
-    <IsFullFramework>false</IsFullFramework>
-  </PropertyGroup>
-
-  <PropertyGroup>
-    <Features>$(Features);FEATURE_APARTMENTSTATE</Features>
-    <Features>$(Features);FEATURE_ASSEMBLY_GETFORWARDEDTYPES</Features>
-    <Features>$(Features);FEATURE_ASSEMBLY_RESOLVE</Features>
-    <Features>$(Features);FEATURE_ASSEMBLYBUILDER_DEFINEDYNAMICASSEMBLY</Features>
-    <Features>$(Features);FEATURE_CODEDOM</Features>
-    <Features>$(Features);FEATURE_COM</Features>
-    <Features>$(Features);FEATURE_CONFIGURATION</Features>
-    <Features>$(Features);FEATURE_CTYPES</Features>
-    <Features>$(Features);FEATURE_CUSTOM_TYPE_DESCRIPTOR</Features>
-    <Features>$(Features);FEATURE_EXCEPTION_STATE</Features>
-    <Features>$(Features);FEATURE_FILESYSTEM</Features>
-    <Features>$(Features);FEATURE_FULL_CRYPTO</Features>
-    <Features>$(Features);FEATURE_FULL_NET</Features>
-    <Features>$(Features);FEATURE_LCG</Features>
-    <Features>$(Features);FEATURE_LOADWITHPARTIALNAME</Features>
-    <Features>$(Features);FEATURE_METADATA_READER</Features>
-    <Features>$(Features);FEATURE_MMAP</Features>
-    <Features>$(Features);FEATURE_NATIVE</Features>
-    <Features>$(Features);FEATURE_PIPES</Features>
-    <Features>$(Features);FEATURE_PROCESS</Features>
-    <Features>$(Features);FEATURE_REFEMIT</Features>
-    <Features>$(Features);FEATURE_REGISTRY</Features>
-    <Features>$(Features);FEATURE_RUNTIMEINFORMATION</Features>
-    <Features>$(Features);FEATURE_SECURITY_RULES</Features>
-    <Features>$(Features);FEATURE_SERIALIZATION</Features>
-    <Features>$(Features);FEATURE_STACK_TRACE</Features>
-    <Features>$(Features);FEATURE_SYNC_SOCKETS</Features>
-    <Features>$(Features);FEATURE_THREAD</Features>
-    <Features>$(Features);FEATURE_XMLDOC</Features>
-  </PropertyGroup>
-</Project>
diff --git a/Build/steps.yml b/Build/steps.yml
index 12a52759c..5903af548 100644
--- a/Build/steps.yml
+++ b/Build/steps.yml
@@ -25,22 +25,22 @@ steps:
     displayName: Grab Package Version
 
   - task: UseDotNet@2
-    displayName: Install .NET Core 3.1 runtime for testing
+    displayName: Install .NET 6.0 runtime for testing
     inputs:
       packageType: 'runtime'
-      version: '3.1.x'
+      version: '6.0.x'
 
   - task: UseDotNet@2
-    displayName: Install .NET 6.0 runtime for testing
+    displayName: Install .NET 8.0 runtime for testing
     inputs:
       packageType: 'runtime'
-      version: '6.0.x'
+      version: '8.0.x'
 
   - task: UseDotNet@2
-    displayName: Install .NET 8.0 SDK for build
+    displayName: Install .NET 9.0 SDK for build
     inputs:
       packageType: 'sdk'
-      version: '8.0.x'
+      version: '9.0.x'
 
   # Set Mono version on macOS
   - ${{ if eq(parameters.os, 'macOS') }}:
diff --git a/IronPython.sln b/IronPython.sln
index 3de1c02d7..f7c936d83 100644
--- a/IronPython.sln
+++ b/IronPython.sln
@@ -41,7 +41,6 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Build", "Build", "{17737ACB
 		Build\net8.0.props = Build\net8.0.props
 		Build\net9.0-windows.props = Build\net9.0-windows.props
 		Build\net9.0.props = Build\net9.0.props
-		Build\netcoreapp3.1.props = Build\netcoreapp3.1.props
 		Build\netstandard2.0.props = Build\netstandard2.0.props
 		Build\steps.yml = Build\steps.yml
 		Build\Tasks.Targets = Build\Tasks.Targets
diff --git a/Package/nuget/IronPython.nuspec b/Package/nuget/IronPython.nuspec
index d2334abc2..491d14977 100644
--- a/Package/nuget/IronPython.nuspec
+++ b/Package/nuget/IronPython.nuspec
@@ -29,10 +29,6 @@ This package contains the IronPython interpreter engine.</description>
         <dependency id="Microsoft.Win32.Registry" version="4.7.0" />
         <dependency id="Mono.Unix" version="7.1.0-final.1.21458.1" />
       </group>
-      <group targetFramework="net6.0">
-        <dependency id="DynamicLanguageRuntime" version="1.3.5" />
-        <dependency id="Mono.Unix" version="7.1.0-final.1.21458.1" />
-      </group>
       <group targetFramework="net8.0">
         <dependency id="DynamicLanguageRuntime" version="1.3.5" />
         <dependency id="Mono.Unix" version="7.1.0-final.1.21458.1" />
@@ -40,9 +36,9 @@ This package contains the IronPython interpreter engine.</description>
     </dependencies>
   </metadata>
   <files>
-    <file src="**\IronPython*.dll" target="lib" exclude="**\IronPythonTest.dll;**\DLLs\*.dll;netcoreapp3.1\**\*;net9.0*\**\*" />
-    <file src="**\IronPython*.pdb" target="lib" exclude="**\IronPythonTest.pdb;**\DLLs\*.pdb;netcoreapp3.1\**\*;net9.0*\**\*" />
-    <file src="**\IronPython*.xml" target="lib" exclude="**\IronPythonTest.xml;**\DLLs\*.xml;netcoreapp3.1\**\*;net9.0*\**\*" />
+    <file src="**\IronPython*.dll" target="lib" exclude="**\IronPythonTest.dll;**\DLLs\*.dll;net6.0\**\*;net9.0*\**\*" />
+    <file src="**\IronPython*.pdb" target="lib" exclude="**\IronPythonTest.pdb;**\DLLs\*.pdb;net6.0\**\*;net9.0*\**\*" />
+    <file src="**\IronPython*.xml" target="lib" exclude="**\IronPythonTest.xml;**\DLLs\*.xml;net6.0\**\*;net9.0*\**\*" />
     <file src="LICENSE" />
     <file src="..\..\..\nuget\README.md" target="" />
     <file src="..\..\..\..\Documentation\logo.png" target="" />
diff --git a/Package/zip/Zip.Packaging.targets b/Package/zip/Zip.Packaging.targets
index bec14c1fa..cb5db9c81 100644
--- a/Package/zip/Zip.Packaging.targets
+++ b/Package/zip/Zip.Packaging.targets
@@ -4,7 +4,7 @@
     <MakeDir Directories="$(PackageDir)" Condition="!Exists('$(PackageDir)')"/>
 
     <ItemGroup>
-      <ZipFiles Include="$(StageDir)\**\*.*" Exclude="$(StageDir)\README.md;$(StageDir)\**\*.pdb;$(StageDir)\netstandard2.0\**\*;$(StageDir)\netcoreapp3.1\**\*;$(StageDir)\net9.0*\**\*" />
+      <ZipFiles Include="$(StageDir)\**\*.*" Exclude="$(StageDir)\README.md;$(StageDir)\**\*.pdb;$(StageDir)\netstandard2.0\**\*;$(StageDir)\net6.0\**\*;$(StageDir)\net9.0*\**\*" />
       <ZipFiles Include="README.md" Link="$(MSBuildThisFileDirectory)README.md" />
       <ZipFiles Include="scripts/Enter-IronPythonEnvironment.ps1" Link="$(RootDir)Src\Scripts\Enter-IronPythonEnvironment.ps1" />
       <ZipFiles Include="scripts/Install-IronPython.ps1" Link="$(RootDir)Src\Scripts\Install-IronPython.ps1" />
diff --git a/Src/DLR b/Src/DLR
index 7e887d984..6e2f41a27 160000
--- a/Src/DLR
+++ b/Src/DLR
@@ -1 +1 @@
-Subproject commit 7e887d9848dbfeca268814aeb237c83dc1244c8a
+Subproject commit 6e2f41a27a74978026d869507f404b3d8575e3b8
diff --git a/Src/IronPythonConsole/IronPythonConsole.csproj b/Src/IronPythonConsole/IronPythonConsole.csproj
index a933ddd3f..a66fcd7a3 100644
--- a/Src/IronPythonConsole/IronPythonConsole.csproj
+++ b/Src/IronPythonConsole/IronPythonConsole.csproj
@@ -1,9 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0</TargetFrameworks>
-    <!-- EOL netcoreapp3.1 is used to test netstandard2.0 assemblies -->
-    <CheckEolTargetFramework>false</CheckEolTargetFramework>
+    <TargetFrameworks>net462;net6.0;net8.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <RootNamespace>IronPythonConsole</RootNamespace>
     <AssemblyName>ipy</AssemblyName>
@@ -20,12 +18,6 @@
       <OutputItemType>Content</OutputItemType>
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </ProjectReference>
-    <!-- add reference so it gets copied to the netcoreapp3.1 folder for testing -->
-    <ProjectReference Include="..\IronPython.SQLite\IronPython.SQLite.csproj" Condition="$(TargetFramework) == 'netcoreapp3.1'">
-      <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
-      <OutputItemType>Content</OutputItemType>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-    </ProjectReference>
   </ItemGroup>
 
   <ItemGroup Condition=" '$(IsFullFramework)' == 'true' AND !$([MSBuild]::IsOSPlatform('WINDOWS')) ">
diff --git a/Src/IronPythonTest/IronPythonTest.csproj b/Src/IronPythonTest/IronPythonTest.csproj
index 95d56194d..4a76e9f88 100644
--- a/Src/IronPythonTest/IronPythonTest.csproj
+++ b/Src/IronPythonTest/IronPythonTest.csproj
@@ -1,9 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0</TargetFrameworks>
-    <!-- EOL netcoreapp3.1 is used to test netstandard2.0 assemblies -->
-    <CheckEolTargetFramework>false</CheckEolTargetFramework>
+    <TargetFrameworks>net462;net6.0;net8.0</TargetFrameworks>
     <PreventStaging>true</PreventStaging>
   </PropertyGroup>
 
diff --git a/make.ps1 b/make.ps1
index 32786dd37..e4575bee7 100755
--- a/make.ps1
+++ b/make.ps1
@@ -4,7 +4,7 @@ Param(
     [Parameter(Position=1)]
     [String] $target = "build",
     [String] $configuration = "Release",
-    [String[]] $frameworks=@('net462','netcoreapp3.1','net6.0','net8.0'),
+    [String[]] $frameworks=@('net462','net6.0','net8.0'),
     [String] $platform = $null,  # auto-detect
     [switch] $runIgnored,
     [int] $jobs = [System.Environment]::ProcessorCount