diff --git a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
old mode 100755
new mode 100644
index 9be77c8875dba..14467c5f14518
--- a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
+++ b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
@@ -17,7 +17,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Newtonsoft.Json" Version="9.0.1" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="NUnit" Version="3.6.0" />
     <PackageReference Include="NUnitLite" Version="3.6.0" />
     <PackageReference Include="NUnit.ConsoleRunner" Version="3.6.0" />