diff --git a/Directory.Build.props b/Directory.Build.props
index 04381d36..5548005c 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -51,37 +51,9 @@
   <ItemGroup>
     <PackageReference Include="JetBrains.Annotations" PrivateAssets="All" />
     <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" PrivateAssets="All" />
-    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Condition=" '$(OS)' != 'Windows_NT' " PrivateAssets="All" />
+    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" PrivateAssets="All" />
   </ItemGroup>
 
-  <PropertyGroup Condition=" '$(TargetFramework)' != 'net461' ">
-    <DefineConstants>$(DefineConstants);SUPPORTS_ECDSA</DefineConstants>
-  </PropertyGroup>
-
-  <PropertyGroup Condition=" '$(TargetFramework)' != 'net461' And '$(TargetFramework)' != 'netstandard2.0' ">
-    <DefineConstants>$(DefineConstants);SUPPORTS_CERTIFICATE_GENERATION</DefineConstants>
-    <DefineConstants>$(DefineConstants);SUPPORTS_DIRECT_KEY_CREATION_WITH_SPECIFIED_SIZE</DefineConstants>
-    <DefineConstants>$(DefineConstants);SUPPORTS_EPHEMERAL_KEY_SETS</DefineConstants>
-    <DefineConstants>$(DefineConstants);SUPPORTS_KEY_DERIVATION_WITH_SPECIFIED_HASH_ALGORITHM</DefineConstants>
-  </PropertyGroup>
-
-  <PropertyGroup Condition=" '$(TargetFramework)' != 'net461' And
-                             '$(TargetFramework)' != 'net472' And
-                             '$(TargetFramework)' != 'netstandard2.0' ">
-    <DefineConstants>$(DefineConstants);SUPPORTS_BASE64_SPAN_CONVERSION</DefineConstants>
-    <DefineConstants>$(DefineConstants);SUPPORTS_STATIC_RANDOM_NUMBER_GENERATOR_METHODS</DefineConstants>
-    <DefineConstants>$(DefineConstants);SUPPORTS_TIME_CONSTANT_COMPARISONS</DefineConstants>
-  </PropertyGroup>
-
-  <PropertyGroup Condition=" '$(TargetFramework)' != 'net461' And
-                             '$(TargetFramework)' != 'net472' And
-                             '$(TargetFramework)' != 'netcoreapp2.1' And
-                             '$(TargetFramework)' != 'netstandard2.0' ">
-    <DefineConstants>$(DefineConstants);SUPPORTS_BCL_ASYNC_ENUMERABLE</DefineConstants>
-    <DefineConstants>$(DefineConstants);SUPPORTS_GENERIC_HOST</DefineConstants>
-    <DefineConstants>$(DefineConstants);SUPPORTS_SERVICE_PROVIDER_IN_HTTP_MESSAGE_HANDLER_BUILDER</DefineConstants>
-  </PropertyGroup>
-
   <ItemGroup>
     <ProjectCapability Include="DynamicDependentFile" />
     <ProjectCapability Include="DynamicFileNesting" />
diff --git a/Directory.Build.targets b/Directory.Build.targets
index af60f0fe..0af844a1 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -15,6 +15,59 @@
     <PublicSign>false</PublicSign>
   </PropertyGroup>
 
+  <PropertyGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETCoreApp' Or
+                            ('$(TargetFrameworkIdentifier)' == '.NETFramework' And
+                              $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '4.7'))) Or
+                            ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                              $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '1.6'))) ">
+    <DefineConstants>$(DefineConstants);SUPPORTS_ECDSA</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.0'))) Or
+                             ('$(TargetFrameworkIdentifier)' == '.NETFramework' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '4.7.2'))) Or
+                             ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) ">
+    <DefineConstants>$(DefineConstants);SUPPORTS_CERTIFICATE_GENERATION</DefineConstants>
+    <DefineConstants>$(DefineConstants);SUPPORTS_DIRECT_KEY_CREATION_WITH_SPECIFIED_SIZE</DefineConstants>
+    <DefineConstants>$(DefineConstants);SUPPORTS_EPHEMERAL_KEY_SETS</DefineConstants>
+    <DefineConstants>$(DefineConstants);SUPPORTS_KEY_DERIVATION_WITH_SPECIFIED_HASH_ALGORITHM</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) Or
+                             ('$(TargetFrameworkIdentifier)' == '.NETFramework' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '4.8'))) Or
+                             ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) ">
+    <DefineConstants>$(DefineConstants);SUPPORTS_CERTIFICATE_HASHING_WITH_SPECIFIED_ALGORITHM</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) Or
+                             ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) ">
+    <DefineConstants>$(DefineConstants);SUPPORTS_BASE64_SPAN_CONVERSION</DefineConstants>
+    <DefineConstants>$(DefineConstants);SUPPORTS_STATIC_RANDOM_NUMBER_GENERATOR_METHODS</DefineConstants>
+    <DefineConstants>$(DefineConstants);SUPPORTS_TIME_CONSTANT_COMPARISONS</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.2'))) Or
+                             ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) ">
+    <DefineConstants>$(DefineConstants);SUPPORTS_GENERIC_HOST</DefineConstants>
+    <DefineConstants>$(DefineConstants);SUPPORTS_SERVICE_PROVIDER_IN_HTTP_MESSAGE_HANDLER_BUILDER</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition=" ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '3.0'))) Or
+                             ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                               $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) ">
+    <DefineConstants>$(DefineConstants);SUPPORTS_BCL_ASYNC_ENUMERABLE</DefineConstants>
+  </PropertyGroup>
+
   <!--
     Note: Entity Framework Core 2.x references System.Interactive.Async 3.x, that includes
     its own IAsyncEnumerable. To work around collisions between this type and the new type
diff --git a/Directory.Packages.props b/Directory.Packages.props
index e5bbd452..8ef272ab 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -24,8 +24,12 @@
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or
-                         '$(TargetFramework)' == 'netstandard2.0' Or
-                         '$(TargetFramework)' == 'netcoreapp2.1'">
+                        ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And
+                          $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.0')) And
+                          $([MSBuild]::VersionLessThan($(TargetFrameworkVersion), '3.0'))) Or
+                        ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                          $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.0')) And
+                          $([MSBuild]::VersionLessThan($(TargetFrameworkVersion), '2.1'))) ">
     <PackageVersion Include="Microsoft.AspNetCore.Authentication" Version="2.1.0" />
     <PackageVersion Include="Microsoft.AspNetCore.Authentication.OpenIdConnect" Version="2.1.0" />
     <PackageVersion Include="Microsoft.AspNetCore.DataProtection" Version="2.1.0" />
@@ -45,7 +49,11 @@
     <PackageVersion Include="Microsoft.Extensions.WebEncoders" Version="2.1.0" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.1' Or '$(TargetFramework)' == 'netcoreapp3.1' ">
+  <ItemGroup Condition=" ('$(TargetFrameworkIdentifier)' == '.NETCoreApp' And
+                           $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '3.0')) And
+                           $([MSBuild]::VersionLessThan($(TargetFrameworkVersion), '5.0'))) Or
+                         ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                           $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '2.1'))) ">
     <PackageVersion Include="Microsoft.AspNetCore.Authentication.OpenIdConnect" Version="3.1.0" />
     <PackageVersion Include="Microsoft.AspNetCore.DataProtection" Version="3.1.0" />
     <PackageVersion Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="3.1.0" />
diff --git a/src/OpenIddict.Abstractions/OpenIddict.Abstractions.csproj b/src/OpenIddict.Abstractions/OpenIddict.Abstractions.csproj
index 0e312257..ec978afb 100644
--- a/src/OpenIddict.Abstractions/OpenIddict.Abstractions.csproj
+++ b/src/OpenIddict.Abstractions/OpenIddict.Abstractions.csproj
@@ -15,7 +15,9 @@
     <PackageReference Include="System.Text.Json" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or '$(TargetFramework)' == 'netstandard2.0' ">
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or
+                        ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                          $([MSBuild]::VersionLessThan($(TargetFrameworkVersion), '2.1'))) ">
     <PackageReference Include="Microsoft.Bcl.HashCode" />
   </ItemGroup>
 
diff --git a/src/OpenIddict.Core/OpenIddict.Core.csproj b/src/OpenIddict.Core/OpenIddict.Core.csproj
index b331eba0..96733c4b 100644
--- a/src/OpenIddict.Core/OpenIddict.Core.csproj
+++ b/src/OpenIddict.Core/OpenIddict.Core.csproj
@@ -23,7 +23,9 @@
     <Reference Include="System.ComponentModel.DataAnnotations" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or '$(TargetFramework)' == 'netstandard2.0' ">
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or
+                        ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                          $([MSBuild]::VersionLessThan($(TargetFrameworkVersion), '2.1'))) ">
     <PackageReference Include="Portable.BouncyCastle" />
   </ItemGroup>
 
diff --git a/src/OpenIddict.Server/OpenIddict.Server.csproj b/src/OpenIddict.Server/OpenIddict.Server.csproj
index ad8f04ec..e3d1e528 100644
--- a/src/OpenIddict.Server/OpenIddict.Server.csproj
+++ b/src/OpenIddict.Server/OpenIddict.Server.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;net472;netcoreapp2.1;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>net461;net472;net48;netcoreapp2.1;netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
   </PropertyGroup>
 
   <PropertyGroup>
@@ -21,9 +21,9 @@ To use the server feature on ASP.NET Core or OWIN/Katana, reference the OpenIddi
     <PackageReference Include="Microsoft.IdentityModel.JsonWebTokens" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net461' Or
-                         '$(TargetFramework)' == 'net472' Or
-                         '$(TargetFramework)' == 'netstandard2.0' ">
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' Or
+                        ('$(TargetFrameworkIdentifier)' == '.NETStandard' And
+                          $([MSBuild]::VersionLessThan($(TargetFrameworkVersion), '2.1'))) ">
     <PackageReference Include="Portable.BouncyCastle" />
   </ItemGroup>
 
diff --git a/test/OpenIddict.Server.AspNetCore.IntegrationTests/OpenIddict.Server.AspNetCore.IntegrationTests.csproj b/test/OpenIddict.Server.AspNetCore.IntegrationTests/OpenIddict.Server.AspNetCore.IntegrationTests.csproj
index d3c3eff0..f7e49984 100644
--- a/test/OpenIddict.Server.AspNetCore.IntegrationTests/OpenIddict.Server.AspNetCore.IntegrationTests.csproj
+++ b/test/OpenIddict.Server.AspNetCore.IntegrationTests/OpenIddict.Server.AspNetCore.IntegrationTests.csproj
@@ -1,13 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;net472;netcoreapp2.1;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>net461;net472;net48;netcoreapp2.1;netcoreapp3.1</TargetFrameworks>
   </PropertyGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'netcoreapp3.1' ">
-    <FrameworkReference Include="Microsoft.AspNetCore.App" />
-  </ItemGroup>
-
   <ItemGroup>
     <ProjectReference Include="..\..\src\OpenIddict.Server.AspNetCore\OpenIddict.Server.AspNetCore.csproj" />
     <ProjectReference Include="..\OpenIddict.Server.IntegrationTests\OpenIddict.Server.IntegrationTests.csproj" />
@@ -17,7 +13,7 @@
     <PackageReference Include="Microsoft.AspNetCore.TestHost" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net472' ">
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' ">
     <Reference Include="System.Net.Http" />
   </ItemGroup>
 
diff --git a/test/OpenIddict.Server.IntegrationTests/OpenIddict.Server.IntegrationTests.csproj b/test/OpenIddict.Server.IntegrationTests/OpenIddict.Server.IntegrationTests.csproj
index a0a5f824..fbc6a480 100644
--- a/test/OpenIddict.Server.IntegrationTests/OpenIddict.Server.IntegrationTests.csproj
+++ b/test/OpenIddict.Server.IntegrationTests/OpenIddict.Server.IntegrationTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;net472;netcoreapp2.1;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>net461;net472;net48;netcoreapp2.1;netcoreapp3.1</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
@@ -22,7 +22,7 @@
     <PackageReference Include="System.Linq.Async" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net472' ">
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' ">
     <Reference Include="System.Net.Http" />
   </ItemGroup>
 
diff --git a/test/OpenIddict.Server.Owin.IntegrationTests/OpenIddict.Server.Owin.IntegrationTests.csproj b/test/OpenIddict.Server.Owin.IntegrationTests/OpenIddict.Server.Owin.IntegrationTests.csproj
index e28bcb71..9e0afed0 100644
--- a/test/OpenIddict.Server.Owin.IntegrationTests/OpenIddict.Server.Owin.IntegrationTests.csproj
+++ b/test/OpenIddict.Server.Owin.IntegrationTests/OpenIddict.Server.Owin.IntegrationTests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net461;net472</TargetFrameworks>
+    <TargetFrameworks>net461;net472;net48</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>
@@ -13,7 +13,7 @@
     <PackageReference Include="Microsoft.Owin.Testing" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net472' ">
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' ">
     <Reference Include="System.Net.Http" />
   </ItemGroup>
 
diff --git a/test/OpenIddict.Server.Tests/OpenIddict.Server.Tests.csproj b/test/OpenIddict.Server.Tests/OpenIddict.Server.Tests.csproj
index f2179c04..ab1a88d0 100644
--- a/test/OpenIddict.Server.Tests/OpenIddict.Server.Tests.csproj
+++ b/test/OpenIddict.Server.Tests/OpenIddict.Server.Tests.csproj
@@ -18,7 +18,7 @@
     <ProjectReference Include="..\..\src\OpenIddict.Server\OpenIddict.Server.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net472' Or '$(TargetFramework)' == 'net461' ">
+  <ItemGroup Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' ">
     <Reference Include="System.Net.Http" />
   </ItemGroup>