diff --git a/Directory.Build.targets b/Directory.Build.targets
index 212c9878c2b45173ae726bb6aeba3577fa57f29f..2486a20a85efccf0c24fbd11170f3c0b08aa426e 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -81,9 +81,12 @@
 
   <ItemGroup>
     <KnownFrameworkReference Update="Microsoft.NETCore.App">
-      <LatestRuntimeFrameworkVersion>$(MicrosoftNETCoreAppPackageVersion)</LatestRuntimeFrameworkVersion>
-      <DefaultRuntimeFrameworkVersion Condition="'$(IsServicingBuild)' != 'true'">$(MicrosoftNETCoreAppPackageVersion)</DefaultRuntimeFrameworkVersion>
-      <TargetingPackVersion Condition="'$(IsServicingBuild)' != 'true'">$(MicrosoftNETCoreAppPackageVersion)</TargetingPackVersion>
+      <!-- Always update the 'latest version', whether the repo is servicing or not. -->
+      <LatestRuntimeFrameworkVersion Condition="'%(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">$(MicrosoftNETCoreAppPackageVersion)</LatestRuntimeFrameworkVersion>
+      <!-- Only update the default runtime version for preview builds. -->
+      <DefaultRuntimeFrameworkVersion Condition="'%(TargetFramework)' == '$(DefaultNetCoreTargetFramework)' and '$(IsServicingBuild)' != 'true'">$(MicrosoftNETCoreAppPackageVersion)</DefaultRuntimeFrameworkVersion>
+      <!-- Only update the targeting pack version for preview builds. -->
+      <TargetingPackVersion Condition="'%(TargetFramework)' == '$(DefaultNetCoreTargetFramework)' and '$(IsServicingBuild)' != 'true'">$(MicrosoftNETCoreAppPackageVersion)</TargetingPackVersion>
     </KnownFrameworkReference>
 
     <KnownFrameworkReference Condition="'$(UseAspNetCoreSharedRuntime)' != 'true'" Remove="Microsoft.AspNetCore.App" />
@@ -95,6 +98,10 @@
       <TargetingPackVersion Condition="'$(IsServicingBuild)' != 'true'">$(SharedFxVersion)</TargetingPackVersion>
     </KnownFrameworkReference>
 
+    <KnownFrameworkReference Update="NETStandard.Library">
+      <TargetingPackVersion Condition="'%(TargetFramework)' == 'netstandard2.1' and '$(IsServicingBuild)' != 'true'">$(NETStandardLibraryRefPackageVersion)</TargetingPackVersion>
+    </KnownFrameworkReference>
+
   </ItemGroup>
 
   <!-- Copied from https://github.com/dotnet/arcade/blob/9d0fd805448082c8d55e2434607b481bca70a146/src/Microsoft.DotNet.Arcade.Sdk/tools/RepositoryInfo.targets#L12-L38 -->
diff --git a/eng/SharedFramework.External.props b/eng/SharedFramework.External.props
index d735b0764f92f7db9a27e7a5a0611a74495f6f88..e894b2f988c6780bf2cc7218351ddc844f7d21cd 100644
--- a/eng/SharedFramework.External.props
+++ b/eng/SharedFramework.External.props
@@ -83,7 +83,7 @@
     These compilation references are necessary to compile netstandard2.0 assemblies which are in the shared framework.
     This references are part of Microsoft.NETCore.App, so are listed here as references to be used during compilation only.
   -->
-  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'netstandard2.1'">
     <_CompilationOnlyReference Include="System.Buffers" />
     <_CompilationOnlyReference Include="System.ComponentModel.Annotations" />
     <_CompilationOnlyReference Include="System.Runtime.CompilerServices.Unsafe" />
diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 45a9967926009d771ca1b56b0ce0f59be3ab6e3c..5971f3367b1c9ed74cdea329ce5def1a437cb9c0 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -377,6 +377,10 @@
       <Uri>https://github.com/dotnet/core-setup</Uri>
       <Sha>20426e8c486d8715337cb6438ec70bc3619a514d</Sha>
     </Dependency>
+    <Dependency Name="NETStandard.Library.Ref" Version="2.1.0-preview6-27723-08" CoherentParentDependency="Microsoft.Extensions.Logging">
+      <Uri>https://github.com/dotnet/core-setup</Uri>
+      <Sha>20426e8c486d8715337cb6438ec70bc3619a514d</Sha>
+    </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
     <!-- Listed explicitly to workaround https://github.com/dotnet/cli/issues/10528 -->
diff --git a/eng/Versions.props b/eng/Versions.props
index 557ca946e5ec66e29cb473525ac769c3d74b2c36..553e0d4c7f9aca979e7fffe0a9840e0a1c220687 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -25,6 +25,7 @@
     <!-- Packages from dotnet/core-setup -->
     <MicrosoftExtensionsDependencyModelPackageVersion>3.0.0-preview6-27723-08</MicrosoftExtensionsDependencyModelPackageVersion>
     <MicrosoftNETCoreAppPackageVersion>3.0.0-preview6-27723-08</MicrosoftNETCoreAppPackageVersion>
+    <NETStandardLibraryRefPackageVersion>2.1.0-preview6-27723-08</NETStandardLibraryRefPackageVersion>
     <!-- Packages from dotnet/corefx -->
     <MicrosoftCSharpPackageVersion>4.6.0-preview6.19273.5</MicrosoftCSharpPackageVersion>
     <MicrosoftWin32RegistryPackageVersion>4.6.0-preview6.19273.5</MicrosoftWin32RegistryPackageVersion>