diff --git a/Directory.Build.props b/Directory.Build.props
index 6799dfb80..3defbbef9 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -7,7 +7,7 @@
     <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)\cecil.snk</AssemblyOriginatorKeyFile>
-    <DefineConstants Condition=" '$(TargetFramework)' == 'netstandard2.0' OR '$(TargetFramework)' == 'netcoreapp2.1' ">$(DefineConstants);NET_CORE</DefineConstants>
+    <DefineConstants Condition=" '$(TargetFramework)' == 'netstandard2.0' OR '$(TargetFramework)' == 'netcoreapp3.1' ">$(DefineConstants);NET_CORE</DefineConstants>
     <RootNamespace></RootNamespace>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(TargetFramework)' == 'net40' ">
diff --git a/Test/Mono.Cecil.Tests.csproj b/Test/Mono.Cecil.Tests.csproj
index 2d3d8e446..f7762e3f0 100644
--- a/Test/Mono.Cecil.Tests.csproj
+++ b/Test/Mono.Cecil.Tests.csproj
@@ -1,9 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
-  <ItemGroup Condition=" '$(TargetFramework)' == 'netcoreapp2.1' ">
+  <ItemGroup Condition=" '$(TargetFramework)' == 'netcoreapp3.1' ">
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp">
       <Version>2.10.0</Version>
     </PackageReference>
diff --git a/rocks/Test/Mono.Cecil.Rocks.Tests.csproj b/rocks/Test/Mono.Cecil.Rocks.Tests.csproj
index 5bab17633..a15fce183 100644
--- a/rocks/Test/Mono.Cecil.Rocks.Tests.csproj
+++ b/rocks/Test/Mono.Cecil.Rocks.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\Mono.Cecil.csproj">
diff --git a/symbols/mdb/Test/Mono.Cecil.Mdb.Tests.csproj b/symbols/mdb/Test/Mono.Cecil.Mdb.Tests.csproj
index 8475ec4c1..92da7f5ca 100644
--- a/symbols/mdb/Test/Mono.Cecil.Mdb.Tests.csproj
+++ b/symbols/mdb/Test/Mono.Cecil.Mdb.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\..\..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\Mono.Cecil.csproj">
diff --git a/symbols/pdb/Test/Mono.Cecil.Pdb.Tests.csproj b/symbols/pdb/Test/Mono.Cecil.Pdb.Tests.csproj
index 38112e21a..8baa446e8 100644
--- a/symbols/pdb/Test/Mono.Cecil.Pdb.Tests.csproj
+++ b/symbols/pdb/Test/Mono.Cecil.Pdb.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="Current">
   <Import Project="..\..\..\Mono.Cecil.Tests.props" />
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.1;net40</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net40</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\..\Mono.Cecil.csproj">