diff --git a/src/OpenIddict.Core/OpenIddict.Core.csproj b/src/OpenIddict.Core/OpenIddict.Core.csproj
index f412e23d..b331eba0 100644
--- a/src/OpenIddict.Core/OpenIddict.Core.csproj
+++ b/src/OpenIddict.Core/OpenIddict.Core.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;net472;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net461;net472;netcoreapp2.1;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
   </PropertyGroup>
 
   <PropertyGroup>
diff --git a/src/OpenIddict.EntityFrameworkCore/OpenIddict.EntityFrameworkCore.csproj b/src/OpenIddict.EntityFrameworkCore/OpenIddict.EntityFrameworkCore.csproj
index 32e7cd2a..64c8840d 100644
--- a/src/OpenIddict.EntityFrameworkCore/OpenIddict.EntityFrameworkCore.csproj
+++ b/src/OpenIddict.EntityFrameworkCore/OpenIddict.EntityFrameworkCore.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net461;netcoreapp2.1;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
   </PropertyGroup>
 
   <PropertyGroup>
diff --git a/src/OpenIddict.MongoDb/OpenIddict.MongoDb.csproj b/src/OpenIddict.MongoDb/OpenIddict.MongoDb.csproj
index 212319a1..189920ca 100644
--- a/src/OpenIddict.MongoDb/OpenIddict.MongoDb.csproj
+++ b/src/OpenIddict.MongoDb/OpenIddict.MongoDb.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net461;netcoreapp2.1;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
     <SignAssembly>false</SignAssembly>
     <PublicSign>false</PublicSign>
   </PropertyGroup>
diff --git a/src/OpenIddict.Server.DataProtection/OpenIddict.Server.DataProtection.csproj b/src/OpenIddict.Server.DataProtection/OpenIddict.Server.DataProtection.csproj
index 78d4be56..22f92d23 100644
--- a/src/OpenIddict.Server.DataProtection/OpenIddict.Server.DataProtection.csproj
+++ b/src/OpenIddict.Server.DataProtection/OpenIddict.Server.DataProtection.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net461;netcoreapp2.1;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
   </PropertyGroup>
 
   <PropertyGroup>
diff --git a/src/OpenIddict/OpenIddict.csproj b/src/OpenIddict/OpenIddict.csproj
index 206513bd..eb913676 100644
--- a/src/OpenIddict/OpenIddict.csproj
+++ b/src/OpenIddict/OpenIddict.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net461;netcoreapp2.1;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
     <IncludeBuildOutput>false</IncludeBuildOutput>
     <IncludeSymbols>false</IncludeSymbols>
   </PropertyGroup>