diff --git a/src/libraries/Microsoft.Extensions.Caching.Abstractions/ref/Microsoft.Extensions.Caching.Abstractions.csproj b/src/libraries/Microsoft.Extensions.Caching.Abstractions/ref/Microsoft.Extensions.Caching.Abstractions.csproj
index 50eab405b2874..5a386d5714d4a 100644
--- a/src/libraries/Microsoft.Extensions.Caching.Abstractions/ref/Microsoft.Extensions.Caching.Abstractions.csproj
+++ b/src/libraries/Microsoft.Extensions.Caching.Abstractions/ref/Microsoft.Extensions.Caching.Abstractions.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Caching.Abstractions.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Primitives"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Caching.Abstractions.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Primitives"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Caching.Memory/ref/Microsoft.Extensions.Caching.Memory.csproj b/src/libraries/Microsoft.Extensions.Caching.Memory/ref/Microsoft.Extensions.Caching.Memory.csproj
index 68812807eb947..ea36e245c17e1 100644
--- a/src/libraries/Microsoft.Extensions.Caching.Memory/ref/Microsoft.Extensions.Caching.Memory.csproj
+++ b/src/libraries/Microsoft.Extensions.Caching.Memory/ref/Microsoft.Extensions.Caching.Memory.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Caching.Memory.netstandard2.0.cs" />
@@ -10,7 +10,7 @@
     <Reference Include="Microsoft.Extensions.Logging.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Caching.Memory.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Caching.Abstractions"  />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Abstractions/ref/Microsoft.Extensions.Configuration.Abstractions.csproj b/src/libraries/Microsoft.Extensions.Configuration.Abstractions/ref/Microsoft.Extensions.Configuration.Abstractions.csproj
index cb4bf8226c47c..0e2f639e04641 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.Abstractions/ref/Microsoft.Extensions.Configuration.Abstractions.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.Abstractions/ref/Microsoft.Extensions.Configuration.Abstractions.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.Abstractions.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Primitives"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.Abstractions.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Primitives"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Binder/ref/Microsoft.Extensions.Configuration.Binder.csproj b/src/libraries/Microsoft.Extensions.Configuration.Binder/ref/Microsoft.Extensions.Configuration.Binder.csproj
index fe971910fa594..e01485dcda49a 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.Binder/ref/Microsoft.Extensions.Configuration.Binder.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.Binder/ref/Microsoft.Extensions.Configuration.Binder.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.Binder.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.Binder.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Configuration.CommandLine/ref/Microsoft.Extensions.Configuration.CommandLine.csproj b/src/libraries/Microsoft.Extensions.Configuration.CommandLine/ref/Microsoft.Extensions.Configuration.CommandLine.csproj
index fde3620e6886f..074f010a38679 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.CommandLine/ref/Microsoft.Extensions.Configuration.CommandLine.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.CommandLine/ref/Microsoft.Extensions.Configuration.CommandLine.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.CommandLine.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.CommandLine.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Configuration.EnvironmentVariables/ref/Microsoft.Extensions.Configuration.EnvironmentVariables.csproj b/src/libraries/Microsoft.Extensions.Configuration.EnvironmentVariables/ref/Microsoft.Extensions.Configuration.EnvironmentVariables.csproj
index 7bf045d908d51..1612df673e398 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.EnvironmentVariables/ref/Microsoft.Extensions.Configuration.EnvironmentVariables.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.EnvironmentVariables/ref/Microsoft.Extensions.Configuration.EnvironmentVariables.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.EnvironmentVariables.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.EnvironmentVariables.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Configuration.FileExtensions/ref/Microsoft.Extensions.Configuration.FileExtensions.csproj b/src/libraries/Microsoft.Extensions.Configuration.FileExtensions/ref/Microsoft.Extensions.Configuration.FileExtensions.csproj
index 1f674584666c3..094350e4afdf2 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.FileExtensions/ref/Microsoft.Extensions.Configuration.FileExtensions.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.FileExtensions/ref/Microsoft.Extensions.Configuration.FileExtensions.csproj
@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.FileExtensions.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.FileProviders.Physical"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.FileExtensions.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.FileProviders.Physical"  />
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Ini/ref/Microsoft.Extensions.Configuration.Ini.csproj b/src/libraries/Microsoft.Extensions.Configuration.Ini/ref/Microsoft.Extensions.Configuration.Ini.csproj
index 8e3d6896f3c11..6e40290afd8b4 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.Ini/ref/Microsoft.Extensions.Configuration.Ini.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.Ini/ref/Microsoft.Extensions.Configuration.Ini.csproj
@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.Ini.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.Configuration.FileExtensions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.Ini.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.Configuration.FileExtensions"  />
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Json/ref/Microsoft.Extensions.Configuration.Json.csproj b/src/libraries/Microsoft.Extensions.Configuration.Json/ref/Microsoft.Extensions.Configuration.Json.csproj
index 488418fa9fc58..addd1ffd218b8 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.Json/ref/Microsoft.Extensions.Configuration.Json.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.Json/ref/Microsoft.Extensions.Configuration.Json.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.Json.netstandard2.0.cs" />
@@ -10,7 +10,7 @@
     <Reference Include="System.Text.Json"  />
     <Reference Include="System.Threading.Tasks.Extensions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.Json.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.Configuration.FileExtensions"  />
diff --git a/src/libraries/Microsoft.Extensions.Configuration.UserSecrets/ref/Microsoft.Extensions.Configuration.UserSecrets.csproj b/src/libraries/Microsoft.Extensions.Configuration.UserSecrets/ref/Microsoft.Extensions.Configuration.UserSecrets.csproj
index aaa946ccd2b7c..8c31f90dcd55e 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.UserSecrets/ref/Microsoft.Extensions.Configuration.UserSecrets.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.UserSecrets/ref/Microsoft.Extensions.Configuration.UserSecrets.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.UserSecrets.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Json"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.UserSecrets.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Json"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Configuration.Xml/ref/Microsoft.Extensions.Configuration.Xml.csproj b/src/libraries/Microsoft.Extensions.Configuration.Xml/ref/Microsoft.Extensions.Configuration.Xml.csproj
index 81dca84962eeb..9f706c9429bb2 100644
--- a/src/libraries/Microsoft.Extensions.Configuration.Xml/ref/Microsoft.Extensions.Configuration.Xml.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration.Xml/ref/Microsoft.Extensions.Configuration.Xml.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.Xml.netstandard2.0.cs" />
@@ -9,7 +9,7 @@
     <Reference Include="Microsoft.Extensions.Configuration.FileExtensions"  />
     <Reference Include="System.Security.Cryptography.Xml"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.Xml.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration"  />
     <Reference Include="Microsoft.Extensions.Configuration.FileExtensions"  />
diff --git a/src/libraries/Microsoft.Extensions.Configuration/ref/Microsoft.Extensions.Configuration.csproj b/src/libraries/Microsoft.Extensions.Configuration/ref/Microsoft.Extensions.Configuration.csproj
index 05ed80b364a26..6defcaaf6a33e 100644
--- a/src/libraries/Microsoft.Extensions.Configuration/ref/Microsoft.Extensions.Configuration.csproj
+++ b/src/libraries/Microsoft.Extensions.Configuration/ref/Microsoft.Extensions.Configuration.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Configuration.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Abstractions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Configuration.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Abstractions"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.DependencyInjection/ref/Microsoft.Extensions.DependencyInjection.csproj b/src/libraries/Microsoft.Extensions.DependencyInjection/ref/Microsoft.Extensions.DependencyInjection.csproj
index d0f4865cccb20..dc39334b96f06 100644
--- a/src/libraries/Microsoft.Extensions.DependencyInjection/ref/Microsoft.Extensions.DependencyInjection.csproj
+++ b/src/libraries/Microsoft.Extensions.DependencyInjection/ref/Microsoft.Extensions.DependencyInjection.csproj
@@ -1,9 +1,9 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp3.1;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks>$(DefaultNetCoreTargetFramework);netstandard2.0;netstandard2.1</TargetFrameworks>
   </PropertyGroup>
-  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+  <ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.DependencyInjection.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.FileProviders.Abstractions/ref/Microsoft.Extensions.FileProviders.Abstractions.csproj b/src/libraries/Microsoft.Extensions.FileProviders.Abstractions/ref/Microsoft.Extensions.FileProviders.Abstractions.csproj
index 5a9634f812d5b..cd3104535d987 100644
--- a/src/libraries/Microsoft.Extensions.FileProviders.Abstractions/ref/Microsoft.Extensions.FileProviders.Abstractions.csproj
+++ b/src/libraries/Microsoft.Extensions.FileProviders.Abstractions/ref/Microsoft.Extensions.FileProviders.Abstractions.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.FileProviders.Abstractions.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Primitives"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.FileProviders.Abstractions.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Primitives"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.FileProviders.Composite/ref/Microsoft.Extensions.FileProviders.Composite.csproj b/src/libraries/Microsoft.Extensions.FileProviders.Composite/ref/Microsoft.Extensions.FileProviders.Composite.csproj
index 3a84bbc1903d6..46f117717c008 100644
--- a/src/libraries/Microsoft.Extensions.FileProviders.Composite/ref/Microsoft.Extensions.FileProviders.Composite.csproj
+++ b/src/libraries/Microsoft.Extensions.FileProviders.Composite/ref/Microsoft.Extensions.FileProviders.Composite.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.FileProviders.Composite.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.FileProviders.Abstractions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.FileProviders.Composite.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.FileProviders.Abstractions"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.FileProviders.Physical/ref/Microsoft.Extensions.FileProviders.Physical.csproj b/src/libraries/Microsoft.Extensions.FileProviders.Physical/ref/Microsoft.Extensions.FileProviders.Physical.csproj
index 911986bd25e7a..c662e57343e52 100644
--- a/src/libraries/Microsoft.Extensions.FileProviders.Physical/ref/Microsoft.Extensions.FileProviders.Physical.csproj
+++ b/src/libraries/Microsoft.Extensions.FileProviders.Physical/ref/Microsoft.Extensions.FileProviders.Physical.csproj
@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.FileProviders.Physical.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.FileProviders.Abstractions"  />
     <Reference Include="Microsoft.Extensions.FileSystemGlobbing"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.FileProviders.Physical.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.FileProviders.Abstractions"  />
     <Reference Include="Microsoft.Extensions.FileSystemGlobbing"  />
diff --git a/src/libraries/Microsoft.Extensions.Hosting.Abstractions/ref/Microsoft.Extensions.Hosting.Abstractions.csproj b/src/libraries/Microsoft.Extensions.Hosting.Abstractions/ref/Microsoft.Extensions.Hosting.Abstractions.csproj
index b779045c5c8e6..a0f842ac44061 100644
--- a/src/libraries/Microsoft.Extensions.Hosting.Abstractions/ref/Microsoft.Extensions.Hosting.Abstractions.csproj
+++ b/src/libraries/Microsoft.Extensions.Hosting.Abstractions/ref/Microsoft.Extensions.Hosting.Abstractions.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Hosting.Abstractions.netstandard2.0.cs" />
@@ -11,7 +11,7 @@
     <Reference Include="Microsoft.Extensions.Logging.Abstractions"  />
     <Reference Include="Microsoft.Bcl.AsyncInterfaces"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Hosting.Abstractions.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Abstractions"  />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
diff --git a/src/libraries/Microsoft.Extensions.Hosting/ref/Microsoft.Extensions.Hosting.csproj b/src/libraries/Microsoft.Extensions.Hosting/ref/Microsoft.Extensions.Hosting.csproj
index b5cdd31165974..e75cb1125e05f 100644
--- a/src/libraries/Microsoft.Extensions.Hosting/ref/Microsoft.Extensions.Hosting.csproj
+++ b/src/libraries/Microsoft.Extensions.Hosting/ref/Microsoft.Extensions.Hosting.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netstandard2.1;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Hosting.netstandard2.0.cs" />
@@ -34,7 +34,7 @@
     <Reference Include="Microsoft.Extensions.Logging.EventSource"  />
     <Reference Include="Microsoft.Extensions.Logging.EventLog"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Hosting.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Hosting.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Configuration"  />
diff --git a/src/libraries/Microsoft.Extensions.Http/ref/Microsoft.Extensions.Http.csproj b/src/libraries/Microsoft.Extensions.Http/ref/Microsoft.Extensions.Http.csproj
index 4b1d7520e8014..097173637ff1c 100644
--- a/src/libraries/Microsoft.Extensions.Http/ref/Microsoft.Extensions.Http.csproj
+++ b/src/libraries/Microsoft.Extensions.Http/ref/Microsoft.Extensions.Http.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Http.netstandard2.0.cs" />
@@ -9,7 +9,7 @@
     <Reference Include="Microsoft.Extensions.Logging"  />
     <Reference Include="Microsoft.Extensions.Options"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Http.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Logging"  />
diff --git a/src/libraries/Microsoft.Extensions.Logging.Configuration/ref/Microsoft.Extensions.Logging.Configuration.csproj b/src/libraries/Microsoft.Extensions.Logging.Configuration/ref/Microsoft.Extensions.Logging.Configuration.csproj
index df24ac1b52ba8..7071343de5b6b 100644
--- a/src/libraries/Microsoft.Extensions.Logging.Configuration/ref/Microsoft.Extensions.Logging.Configuration.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.Configuration/ref/Microsoft.Extensions.Logging.Configuration.csproj
@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Logging.Configuration.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
     <Reference Include="Microsoft.Extensions.Options.ConfigurationExtensions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Logging.Configuration.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
     <Reference Include="Microsoft.Extensions.Options.ConfigurationExtensions"  />
diff --git a/src/libraries/Microsoft.Extensions.Logging.Console/ref/Microsoft.Extensions.Logging.Console.csproj b/src/libraries/Microsoft.Extensions.Logging.Console/ref/Microsoft.Extensions.Logging.Console.csproj
index 1bcb18fb2f32a..b82bf7ebde2fa 100644
--- a/src/libraries/Microsoft.Extensions.Logging.Console/ref/Microsoft.Extensions.Logging.Console.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.Console/ref/Microsoft.Extensions.Logging.Console.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Logging.Console.netstandard2.0.cs" />
@@ -9,7 +9,7 @@
     <Reference Include="Microsoft.Extensions.Logging.Configuration"  />
     <Reference Include="Microsoft.Extensions.Logging"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Logging.Console.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Logging.Configuration"  />
diff --git a/src/libraries/Microsoft.Extensions.Logging.Debug/ref/Microsoft.Extensions.Logging.Debug.csproj b/src/libraries/Microsoft.Extensions.Logging.Debug/ref/Microsoft.Extensions.Logging.Debug.csproj
index 9d20b2a46be13..b35fb8a34f998 100644
--- a/src/libraries/Microsoft.Extensions.Logging.Debug/ref/Microsoft.Extensions.Logging.Debug.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.Debug/ref/Microsoft.Extensions.Logging.Debug.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Logging.Debug.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Logging.Debug.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Logging.EventLog/ref/Microsoft.Extensions.Logging.EventLog.csproj b/src/libraries/Microsoft.Extensions.Logging.EventLog/ref/Microsoft.Extensions.Logging.EventLog.csproj
index d74fe72a311c3..19e726785b991 100644
--- a/src/libraries/Microsoft.Extensions.Logging.EventLog/ref/Microsoft.Extensions.Logging.EventLog.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.EventLog/ref/Microsoft.Extensions.Logging.EventLog.csproj
@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Logging.EventLog.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
     <Reference Include="System.Diagnostics.EventLog"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Logging.EventLog.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
     <Reference Include="System.Diagnostics.EventLog"  />
diff --git a/src/libraries/Microsoft.Extensions.Logging.EventSource/ref/Microsoft.Extensions.Logging.EventSource.csproj b/src/libraries/Microsoft.Extensions.Logging.EventSource/ref/Microsoft.Extensions.Logging.EventSource.csproj
index f03cb415975f4..eb007ac3b436c 100644
--- a/src/libraries/Microsoft.Extensions.Logging.EventSource/ref/Microsoft.Extensions.Logging.EventSource.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.EventSource/ref/Microsoft.Extensions.Logging.EventSource.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Logging.EventSource.netstandard2.0.cs" />
@@ -9,7 +9,7 @@
     <Reference Include="System.Text.Json"  />
     <Reference Include="System.Threading.Tasks.Extensions"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Logging.EventSource.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Logging.TraceSource/ref/Microsoft.Extensions.Logging.TraceSource.csproj b/src/libraries/Microsoft.Extensions.Logging.TraceSource/ref/Microsoft.Extensions.Logging.TraceSource.csproj
index 630139f805356..780246fa7a0ef 100644
--- a/src/libraries/Microsoft.Extensions.Logging.TraceSource/ref/Microsoft.Extensions.Logging.TraceSource.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging.TraceSource/ref/Microsoft.Extensions.Logging.TraceSource.csproj
@@ -1,13 +1,13 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Logging.TraceSource.netstandard2.0.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Logging.TraceSource.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Logging"  />
   </ItemGroup>
diff --git a/src/libraries/Microsoft.Extensions.Logging/ref/Microsoft.Extensions.Logging.csproj b/src/libraries/Microsoft.Extensions.Logging/ref/Microsoft.Extensions.Logging.csproj
index 2a3bde701789c..0a6d562eb3c11 100644
--- a/src/libraries/Microsoft.Extensions.Logging/ref/Microsoft.Extensions.Logging.csproj
+++ b/src/libraries/Microsoft.Extensions.Logging/ref/Microsoft.Extensions.Logging.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Logging.netstandard2.0.cs" />
@@ -10,7 +10,7 @@
     <Reference Include="Microsoft.Extensions.Logging.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Logging.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Binder"  />
     <Reference Include="Microsoft.Extensions.DependencyInjection"  />
diff --git a/src/libraries/Microsoft.Extensions.Options.ConfigurationExtensions/ref/Microsoft.Extensions.Options.ConfigurationExtensions.csproj b/src/libraries/Microsoft.Extensions.Options.ConfigurationExtensions/ref/Microsoft.Extensions.Options.ConfigurationExtensions.csproj
index 1127c3ff30ccf..3b29d61c46766 100644
--- a/src/libraries/Microsoft.Extensions.Options.ConfigurationExtensions/ref/Microsoft.Extensions.Options.ConfigurationExtensions.csproj
+++ b/src/libraries/Microsoft.Extensions.Options.ConfigurationExtensions/ref/Microsoft.Extensions.Options.ConfigurationExtensions.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Options.ConfigurationExtensions.netstandard2.0.cs" />
@@ -10,7 +10,7 @@
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Options.ConfigurationExtensions.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.Configuration.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Configuration.Binder"  />
diff --git a/src/libraries/Microsoft.Extensions.Options.DataAnnotations/ref/Microsoft.Extensions.Options.DataAnnotations.csproj b/src/libraries/Microsoft.Extensions.Options.DataAnnotations/ref/Microsoft.Extensions.Options.DataAnnotations.csproj
index 0c4b98069be9a..a7d7979ae8669 100644
--- a/src/libraries/Microsoft.Extensions.Options.DataAnnotations/ref/Microsoft.Extensions.Options.DataAnnotations.csproj
+++ b/src/libraries/Microsoft.Extensions.Options.DataAnnotations/ref/Microsoft.Extensions.Options.DataAnnotations.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Options.DataAnnotations.netstandard2.0.cs" />
@@ -9,7 +9,7 @@
     <Reference Include="Microsoft.Extensions.Options"  />
     <Reference Include="System.ComponentModel.Annotations"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Options.DataAnnotations.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Options"  />
diff --git a/src/libraries/Microsoft.Extensions.Options/ref/Microsoft.Extensions.Options.csproj b/src/libraries/Microsoft.Extensions.Options/ref/Microsoft.Extensions.Options.csproj
index 65eb954f83cfd..8358f43d531a6 100644
--- a/src/libraries/Microsoft.Extensions.Options/ref/Microsoft.Extensions.Options.csproj
+++ b/src/libraries/Microsoft.Extensions.Options/ref/Microsoft.Extensions.Options.csproj
@@ -1,7 +1,7 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Options.netstandard2.0.cs" />
@@ -9,7 +9,7 @@
     <Reference Include="Microsoft.Extensions.Primitives"  />
     <Reference Include="System.ComponentModel.Annotations"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Options.netcoreapp.cs" />
     <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions"  />
     <Reference Include="Microsoft.Extensions.Primitives"  />
diff --git a/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.csproj b/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.csproj
index 76b14f997cf9a..9623f02f73388 100644
--- a/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.csproj
+++ b/src/libraries/Microsoft.Extensions.Primitives/ref/Microsoft.Extensions.Primitives.csproj
@@ -1,14 +1,14 @@
 <!-- This file is automatically generated. -->
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;$(DefaultNetCoreTargetFramework)</TargetFrameworks>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <Compile Include="Microsoft.Extensions.Primitives.netstandard2.0.cs" />
     <Reference Include="System.Memory"  />
     <Reference Include="System.Runtime.CompilerServices.Unsafe"  />
   </ItemGroup>
-<ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+<ItemGroup Condition="'$(TargetFramework)' == '$(DefaultNetCoreTargetFramework)'">
     <Compile Include="Microsoft.Extensions.Primitives.netcoreapp.cs" />
     
   </ItemGroup>