diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index a1c1fdfc..8de3acbf 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,10 +14,6 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - 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:
@@ -30,7 +26,6 @@ jobs:
       uses: actions/setup-dotnet@v4
       with:
         dotnet-version: '9.0.x'
-        include-prerelease: true
     - name: Build
       run: pwsh make.ps1
     - name: Package
@@ -42,9 +37,6 @@ 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.proj b/Build.proj
index fda60715..91d14d63 100644
--- a/Build.proj
+++ b/Build.proj
@@ -108,7 +108,7 @@
           Outputs="$(PackageDir)\DynamicLanguageRuntime.$(PackageVersion).zip">
     <ItemGroup>
       <ZipFiles Include="$(StageDir)\**\*.dll;$(StageDir)\**\*.xml;$(StageDir)\README.md;$(StageDir)\LICENSE"
-                Exclude="$(StageDir)\netcoreapp3.1\*;$(StageDir)\net9.0*\*" />
+                Exclude="$(StageDir)\net6.0\*;$(StageDir)\net9.0*\*" />
     </ItemGroup>
     <Message Text="$(ZipFiles)" />
     <Zip Files="@(ZipFiles)" ZipFileName="$(PackageDir)\DynamicLanguageRuntime.$(PackageVersion).zip" WorkingDirectory="$(StageDir)"/>
diff --git a/Build/steps.yml b/Build/steps.yml
index 9eed332a..5403a31e 100644
--- a/Build/steps.yml
+++ b/Build/steps.yml
@@ -21,12 +21,6 @@ steps:
      Write-Host ("##vso[task.setvariable variable=PackageVersion;isSecret=false;isOutput=true;]$PackageVersion")
     displayName: Grab Package Version
 
-  - task: UseDotNet@2
-    displayName: Install .NET Core 3.1 runtime for testing
-    inputs:
-      packageType: 'runtime'
-      version: '3.1.x'
-
   - task: UseDotNet@2
     displayName: Install .NET 6.0 runtime for testing
     inputs:
@@ -34,9 +28,9 @@ steps:
       version: '6.0.x'
 
   - task: UseDotNet@2
-    displayName: Install .NET 8.0 SDK for build
+    displayName: Install .NET 8.0 runtime for testing
     inputs:
-      packageType: 'sdk'
+      packageType: 'runtime'
       version: '8.0.x'
 
   - task: UseDotNet@2
@@ -44,7 +38,6 @@ steps:
     inputs:
       packageType: 'sdk'
       version: '9.0.x'
-      includePreviewVersions: true
 
   # Set Mono version on macOS
   - ${{ if eq(parameters.os, 'macOS') }}:
diff --git a/Package/nuget/DynamicLanguageRuntime.nuspec b/Package/nuget/DynamicLanguageRuntime.nuspec
index 77128c48..4ec745d3 100644
--- a/Package/nuget/DynamicLanguageRuntime.nuspec
+++ b/Package/nuget/DynamicLanguageRuntime.nuspec
@@ -23,18 +23,15 @@
         <dependency id="System.Reflection.Emit" version="4.7.0" />
         <dependency id="System.Reflection.Emit.Lightweight" version="4.7.0" />
       </group>
-      <group targetFramework="net6.0">
-        <dependency id="System.CodeDom" version="6.0.0" />
-      </group>
       <group targetFramework="net8.0">
         <dependency id="System.CodeDom" version="8.0.0" />
       </group>
     </dependencies>
   </metadata>
   <files>
-    <file src="**\*.dll" target="lib" exclude="netcoreapp3.1\*;net9.0*\*" />
-    <file src="**\*.pdb" target="lib" exclude="netcoreapp3.1\*;net9.0*\*" />
-    <file src="**\*.xml" target="lib" exclude="netcoreapp3.1\*;net9.0*\*" />
+    <file src="**\*.dll" target="lib" exclude="net6.0\*;net9.0*\*" />
+    <file src="**\*.pdb" target="lib" exclude="net6.0\*;net9.0*\*" />
+    <file src="**\*.xml" target="lib" exclude="net6.0\*;net9.0*\*" />
     <file src="README.md;LICENSE" />
   </files>
 </package>
diff --git a/Tests/Metadata/Metadata.csproj b/Tests/Metadata/Metadata.csproj
index 009de736..98c11bd0 100644
--- a/Tests/Metadata/Metadata.csproj
+++ b/Tests/Metadata/Metadata.csproj
@@ -1,9 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0;net9.0</TargetFrameworks>
-    <!-- EOL netcoreapp3.1 is used to test netstandard2.0 assemblies -->
-    <CheckEolTargetFramework>false</CheckEolTargetFramework>
+    <TargetFrameworks>net462;net6.0;net8.0;net9.0</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <DefineConstants>$(DefineConstants);CCI</DefineConstants>
diff --git a/Tests/Microsoft.Dynamic.Test/Microsoft.Dynamic.Test.csproj b/Tests/Microsoft.Dynamic.Test/Microsoft.Dynamic.Test.csproj
index 1fa19c51..d640ebc4 100644
--- a/Tests/Microsoft.Dynamic.Test/Microsoft.Dynamic.Test.csproj
+++ b/Tests/Microsoft.Dynamic.Test/Microsoft.Dynamic.Test.csproj
@@ -1,9 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0;net9.0</TargetFrameworks>
-    <!-- EOL netcoreapp3.1 is used to test netstandard2.0 assemblies -->
-    <CheckEolTargetFramework>false</CheckEolTargetFramework>
+    <TargetFrameworks>net462;net6.0;net8.0;net9.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/Tests/Microsoft.Scripting.Test/Microsoft.Scripting.Test.csproj b/Tests/Microsoft.Scripting.Test/Microsoft.Scripting.Test.csproj
index 616b0f04..133922dd 100644
--- a/Tests/Microsoft.Scripting.Test/Microsoft.Scripting.Test.csproj
+++ b/Tests/Microsoft.Scripting.Test/Microsoft.Scripting.Test.csproj
@@ -1,9 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0;net8.0;net9.0</TargetFrameworks>
-    <!-- EOL netcoreapp3.1 is used to test netstandard2.0 assemblies -->
-    <CheckEolTargetFramework>false</CheckEolTargetFramework>
+    <TargetFrameworks>net462;net6.0;net8.0;net9.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/make.ps1 b/make.ps1
index 8a97f4bf..4e67a6d6 100755
--- a/make.ps1
+++ b/make.ps1
@@ -4,7 +4,7 @@ Param(
     [Parameter(Position=1)]
     [String] $target = "release",
     [String] $configuration = "Release",
-    [String[]] $frameworks=@('net462','netcoreapp3.1','net6.0','net8.0','net9.0'),
+    [String[]] $frameworks=@('net462','net6.0','net8.0','net9.0'),
     [String] $platform = "x64",
     [switch] $runIgnored
 )