diff --git a/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/Microsoft.CodeAnalysis.Analyzer.Testing.csproj b/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/Microsoft.CodeAnalysis.Analyzer.Testing.csproj
index ca9f2396e..f35cd45d1 100644
--- a/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/Microsoft.CodeAnalysis.Analyzer.Testing.csproj
+++ b/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/Microsoft.CodeAnalysis.Analyzer.Testing.csproj
@@ -21,17 +21,18 @@
     </When>
     <When Condition="'$(TargetFramework)' == 'net46'">
       <PropertyGroup>
-        <NuGetApiVersion>4.9.6</NuGetApiVersion>
+        <NuGetApiVersion>4.5.3</NuGetApiVersion>
       </PropertyGroup>
     </When>
     <When Condition="'$(TargetFramework)' == 'netstandard1.6'">
       <PropertyGroup>
-        <NuGetApiVersion>4.9.6</NuGetApiVersion>
+        <NuGetApiVersion>4.5.3</NuGetApiVersion>
       </PropertyGroup>
     </When>
     <Otherwise>
       <PropertyGroup>
-        <NuGetApiVersion>6.3.3</NuGetApiVersion>
+        <NuGetApiVersion>6.3.4</NuGetApiVersion>
+        <DefineConstants>$(DefineConstants);NUGET_SIGNING</DefineConstants>
       </PropertyGroup>
     </Otherwise>
   </Choose>
diff --git a/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/ReferenceAssemblies.cs b/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/ReferenceAssemblies.cs
index 187ec4de1..8ae3bcf2c 100644
--- a/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/ReferenceAssemblies.cs
+++ b/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/ReferenceAssemblies.cs
@@ -19,7 +19,7 @@
 using NuGet.Protocol.Core.Types;
 using NuGet.Resolver;
 
-#if NET46 || NET472 || NETSTANDARD || NETCOREAPP3_1
+#if NUGET_SIGNING
 using NuGet.Packaging.Signing;
 #endif
 
@@ -274,13 +274,13 @@ private async Task<ImmutableArray<MetadataReference>> ResolveCoreAsync(string la
 
                 var globalPathResolver = new PackagePathResolver(SettingsUtility.GetGlobalPackagesFolder(settings));
                 var localPathResolver = new PackagePathResolver(temporaryPackagesFolder);
-#if NET452
+#if NET452 || NET46 || NETSTANDARD1_6
                 var packageExtractionContext = new PackageExtractionContext(logger)
                 {
                     PackageSaveMode = PackageSaveMode.Defaultv3,
                     XmlDocFileSaveMode = XmlDocFileSaveMode.None,
                 };
-#elif NET46 || NET472 || NETSTANDARD1_6 || NETSTANDARD2_0 || NETCOREAPP3_1
+#elif NUGET_SIGNING
                 var packageExtractionContext = new PackageExtractionContext(
                     PackageSaveMode.Defaultv3,
                     XmlDocFileSaveMode.None,
@@ -350,7 +350,7 @@ private async Task<ImmutableArray<MetadataReference>> ResolveCoreAsync(string la
                         if (downloadResult.Status == DownloadResourceResultStatus.AvailableWithoutStream)
                         {
                             await PackageExtractor.ExtractPackageAsync(
-#if !NET452
+#if NUGET_SIGNING
 #pragma warning disable SA1114 // Parameter list should follow declaration
                                 downloadResult.PackageSource,
 #pragma warning restore SA1114 // Parameter list should follow declaration
@@ -364,7 +364,7 @@ await PackageExtractor.ExtractPackageAsync(
                         {
                             Debug.Assert(downloadResult.PackageStream != null, "PackageStream should not be null if download result status != DownloadResourceResultStatus.AvailableWithoutStream");
                             await PackageExtractor.ExtractPackageAsync(
-#if !NET452
+#if NUGET_SIGNING
 #pragma warning disable SA1114 // Parameter list should follow declaration
                                 downloadResult.PackageSource,
 #pragma warning restore SA1114 // Parameter list should follow declaration
@@ -562,7 +562,7 @@ private static async Task GetPackageDependenciesAsync(
                 var dependencyInfo = await dependencyInfoResource.ResolvePackage(
                     packageIdentity,
                     targetFramework,
-#if !NET452
+#if NUGET_SIGNING
                     cacheContext,
 #endif
                     logger,