diff --git a/Rx.NET/Source/tests/Tests.System.Reactive.ApiApprovals/Tests.System.Reactive.ApiApprovals.csproj b/Rx.NET/Source/tests/Tests.System.Reactive.ApiApprovals/Tests.System.Reactive.ApiApprovals.csproj
index 5374d7d390..dc026bc74d 100644
--- a/Rx.NET/Source/tests/Tests.System.Reactive.ApiApprovals/Tests.System.Reactive.ApiApprovals.csproj
+++ b/Rx.NET/Source/tests/Tests.System.Reactive.ApiApprovals/Tests.System.Reactive.ApiApprovals.csproj
@@ -28,7 +28,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.3.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
     <PackageReference Include="ApprovalTests" Version="4.3.0" />
diff --git a/Rx.NET/Source/tests/Tests.System.Reactive/Tests.System.Reactive.csproj b/Rx.NET/Source/tests/Tests.System.Reactive/Tests.System.Reactive.csproj
index 3a5c00374d..446609372a 100644
--- a/Rx.NET/Source/tests/Tests.System.Reactive/Tests.System.Reactive.csproj
+++ b/Rx.NET/Source/tests/Tests.System.Reactive/Tests.System.Reactive.csproj
@@ -17,7 +17,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.3.0" />    
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />    
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.1" />
     <ProjectReference Include="..\..\src\System.Reactive\System.Reactive.csproj" />