diff --git a/.github/workflows/dotnetcore.yml b/.github/workflows/dotnetcore.yml
index c3fcae48db..67bfd6f41f 100644
--- a/.github/workflows/dotnetcore.yml
+++ b/.github/workflows/dotnetcore.yml
@@ -39,7 +39,7 @@ jobs:
     - name: Setup .NET 9.0.x
       uses: actions/setup-dotnet@v4.0.0
       with:
-        dotnet-version: 9.0.100-preview.2.24157.14
+        dotnet-version: 9.0.100-preview.4.24267.66
 
     - name: Run the tests
       run: dotnet test Wilson.sln
diff --git a/build/template-Build-run-tests-sign.yml b/build/template-Build-run-tests-sign.yml
index 4bb46aa90b..1dd091a0e7 100644
--- a/build/template-Build-run-tests-sign.yml
+++ b/build/template-Build-run-tests-sign.yml
@@ -28,7 +28,7 @@ steps:
 - task: UseDotNet@2
   displayName: 'Use .Net Core SDK 9.x'
   inputs:
-    version: 9.0.100-preview.2.24157.14
+    version: 9.0.100-preview.4.24267.66
     includePreviewVersions: true
   condition: eq(variables['TargetNet9'], 'True')
 
diff --git a/src/Microsoft.IdentityModel.Tokens/AsymmetricSignatureProvider.cs b/src/Microsoft.IdentityModel.Tokens/AsymmetricSignatureProvider.cs
index 586465d9c8..682314e625 100644
--- a/src/Microsoft.IdentityModel.Tokens/AsymmetricSignatureProvider.cs
+++ b/src/Microsoft.IdentityModel.Tokens/AsymmetricSignatureProvider.cs
@@ -198,7 +198,7 @@ internal bool ValidKeySize()
         /// <inheritdoc/>
         public override bool Sign(ReadOnlySpan<byte> input, Span<byte> signature, out int bytesWritten)
         {
-            if (input == null || input.Length == 0)
+            if (input.Length == 0)
                 throw LogHelper.LogArgumentNullException(nameof(input));
 
             if (_disposed)
diff --git a/src/Microsoft.IdentityModel.Tokens/SymmetricSignatureProvider.cs b/src/Microsoft.IdentityModel.Tokens/SymmetricSignatureProvider.cs
index 6bd809a768..e066b57f48 100644
--- a/src/Microsoft.IdentityModel.Tokens/SymmetricSignatureProvider.cs
+++ b/src/Microsoft.IdentityModel.Tokens/SymmetricSignatureProvider.cs
@@ -207,7 +207,7 @@ public override byte[] Sign(byte[] input)
         /// <inheritdoc/>
         public override bool Sign(ReadOnlySpan<byte> input, Span<byte> signature, out int bytesWritten)
         {
-            if (input == null || input.Length == 0)
+            if (input.Length == 0)
                 throw LogHelper.LogArgumentNullException(nameof(input));
 
             if (_disposed)