diff --git a/Source/Csla.Analyzers/Csla.Analyzers/Csla.Analyzers.csproj b/Source/Csla.Analyzers/Csla.Analyzers/Csla.Analyzers.csproj
index 5c1432c4a9..0bca505501 100644
--- a/Source/Csla.Analyzers/Csla.Analyzers/Csla.Analyzers.csproj
+++ b/Source/Csla.Analyzers/Csla.Analyzers/Csla.Analyzers.csproj
@@ -16,7 +16,6 @@
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.10.0" PrivateAssets="all" />
     <PackageReference Update="NETStandard.Library" PrivateAssets="all" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All" />
-    <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
   </ItemGroup>
 
   <ItemGroup>
@@ -39,4 +38,11 @@
     </EmbeddedResource>
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
+    <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
+    <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
+    <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
+  </ItemGroup>
+
 </Project>
diff --git a/Source/Csla.Channels.RabbitMq/Csla.Channels.RabbitMq.csproj b/Source/Csla.Channels.RabbitMq/Csla.Channels.RabbitMq.csproj
index 3265bf7a8b..1fa9a16afe 100644
--- a/Source/Csla.Channels.RabbitMq/Csla.Channels.RabbitMq.csproj
+++ b/Source/Csla.Channels.RabbitMq/Csla.Channels.RabbitMq.csproj
@@ -23,4 +23,11 @@
     <ProjectReference Include="..\Csla\Csla.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
+    <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
+    <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
+    <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
+  </ItemGroup>
+
 </Project>
diff --git a/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.Attributes.CSharp/Csla.Generator.AutoImplementProperties.Attributes.CSharp.csproj b/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.Attributes.CSharp/Csla.Generator.AutoImplementProperties.Attributes.CSharp.csproj
index ee2b7a3b8c..b8d3e1ebc0 100644
--- a/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.Attributes.CSharp/Csla.Generator.AutoImplementProperties.Attributes.CSharp.csproj
+++ b/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.Attributes.CSharp/Csla.Generator.AutoImplementProperties.Attributes.CSharp.csproj
@@ -19,5 +19,8 @@
 
   <ItemGroup>
     <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
+    <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
+    <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
+    <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
   </ItemGroup>
 </Project>
diff --git a/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.CSharp/Csla.Generator.AutoImplementProperties.CSharp.csproj b/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.CSharp/Csla.Generator.AutoImplementProperties.CSharp.csproj
index 7c36767d40..bc1580d18d 100644
--- a/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.CSharp/Csla.Generator.AutoImplementProperties.CSharp.csproj
+++ b/Source/Csla.Generators/cs/AutoImplementProperties/Csla.Generator.AutoImplementProperties.CSharp/Csla.Generator.AutoImplementProperties.CSharp.csproj
@@ -33,7 +33,6 @@
     <PackageReference Include="Microsoft.Bcl.HashCode" Version="6.0.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.Common" Version="4.9.2" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.9.2" PrivateAssets="all" />
-     <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
    </ItemGroup>
 
   <ItemGroup>
@@ -46,4 +45,11 @@
                       PrivateAssets="All"/>
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
+    <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
+    <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
+    <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
+  </ItemGroup>
+
 </Project>
diff --git a/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.Attributes.CSharp/Csla.Generator.AutoSerialization.Attributes.CSharp.csproj b/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.Attributes.CSharp/Csla.Generator.AutoSerialization.Attributes.CSharp.csproj
index 4e2ea6e99f..dbca9c7753 100644
--- a/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.Attributes.CSharp/Csla.Generator.AutoSerialization.Attributes.CSharp.csproj
+++ b/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.Attributes.CSharp/Csla.Generator.AutoSerialization.Attributes.CSharp.csproj
@@ -18,5 +18,8 @@
 
   <ItemGroup>
     <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
+    <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
+    <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
+    <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
   </ItemGroup>
 </Project>
diff --git a/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.CSharp/Csla.Generator.AutoSerialization.CSharp.csproj b/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.CSharp/Csla.Generator.AutoSerialization.CSharp.csproj
index 23e232ca23..571c839960 100644
--- a/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.CSharp/Csla.Generator.AutoSerialization.CSharp.csproj
+++ b/Source/Csla.Generators/cs/AutoSerialization/Csla.Generator.AutoSerialization.CSharp/Csla.Generator.AutoSerialization.CSharp.csproj
@@ -32,7 +32,6 @@
    <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.Common" Version="4.9.2" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.9.2" PrivateAssets="all" />
-     <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
    </ItemGroup>
 
   <ItemGroup>
@@ -44,5 +43,12 @@
     <ProjectReference Include="..\Csla.Generator.AutoSerialization.Attributes.CSharp\Csla.Generator.AutoSerialization.Attributes.CSharp.csproj" 
                       PrivateAssets="All" />
   </ItemGroup>
+  
+  <ItemGroup>
+    <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />    
+    <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
+    <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
+    <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
+  </ItemGroup>
 
 </Project>
diff --git a/Source/Csla/Csla.csproj b/Source/Csla/Csla.csproj
index b504a7afe6..5d8651608e 100644
--- a/Source/Csla/Csla.csproj
+++ b/Source/Csla/Csla.csproj
@@ -102,7 +102,6 @@
     <PackageReference Include="System.Text.Json" Version="8.0.5" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All" />
     <PackageReference Include="System.Text.RegularExpressions" Version="4.3.1" />
-    <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />
   </ItemGroup>
   <ItemGroup>
     <None Include="..\..\bin\Release\netstandard2.0\Csla.Analyzers.dll">
@@ -123,5 +122,11 @@
       <LastGenOutput>Resources.Designer.cs</LastGenOutput>
     </EmbeddedResource>
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Backport.System.Threading.Lock" Version="3.1.0" />    
+    <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
+    <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
+    <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
+  </ItemGroup>
 
 </Project>
diff --git a/Source/Directory.Build.props b/Source/Directory.Build.props
index ed9cb0edda..00a74b74d4 100644
--- a/Source/Directory.Build.props
+++ b/Source/Directory.Build.props
@@ -20,9 +20,4 @@
    <NeutralLanguage>en-US</NeutralLanguage>
    <DefaultLanguage>en-US</DefaultLanguage>
  </PropertyGroup>
- <ItemGroup>
-  <Using Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="System.Threading.Lock" />
-  <Using Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Alias="Lock" Include="Backport.System.Threading.Lock" />
-  <Using Alias="LockFactory" Include="Backport.System.Threading.LockFactory" />
- </ItemGroup>
 </Project>
\ No newline at end of file