diff --git a/Test/DurableTask.Core.Tests/ExceptionHandlingIntegrationTests.cs b/Test/DurableTask.Core.Tests/ExceptionHandlingIntegrationTests.cs
index 6c2e051d1..9e8042254 100644
--- a/Test/DurableTask.Core.Tests/ExceptionHandlingIntegrationTests.cs
+++ b/Test/DurableTask.Core.Tests/ExceptionHandlingIntegrationTests.cs
@@ -61,16 +61,16 @@ await this.worker
             if (mode == ErrorPropagationMode.SerializeExceptions)
             {
                 // The exception should be deserializable
-                InvalidOperationException e = JsonConvert.DeserializeObject<InvalidOperationException>(state.Output);
+                InvalidOperationException? e = JsonConvert.DeserializeObject<InvalidOperationException>(state.Output);
                 Assert.IsNotNull(e);
-                Assert.AreEqual("This is a test exception", e.Message);
+                Assert.AreEqual("This is a test exception", e!.Message);
             }
             else if (mode == ErrorPropagationMode.UseFailureDetails)
             {
                 // The failure details should contain the relevant exception metadata
-                FailureDetails details = JsonConvert.DeserializeObject<FailureDetails>(state.Output);
+                FailureDetails? details = JsonConvert.DeserializeObject<FailureDetails>(state.Output);
                 Assert.IsNotNull(details);
-                Assert.AreEqual(typeof(InvalidOperationException).FullName, details.ErrorType);
+                Assert.AreEqual(typeof(InvalidOperationException).FullName, details!.ErrorType);
                 Assert.IsTrue(details.IsCausedBy<InvalidOperationException>());
                 Assert.IsTrue(details.IsCausedBy<Exception>()); // check that base types work too
                 Assert.AreEqual("This is a test exception", details.ErrorMessage);
diff --git a/src/DurableTask.Emulator/DurableTask.Emulator.csproj b/src/DurableTask.Emulator/DurableTask.Emulator.csproj
index 9e5383468..e165bbe31 100644
--- a/src/DurableTask.Emulator/DurableTask.Emulator.csproj
+++ b/src/DurableTask.Emulator/DurableTask.Emulator.csproj
@@ -13,7 +13,7 @@
   </ItemGroup>
   
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
-    <PackageReference Include="Newtonsoft.Json" version="11.0.2" />
+    <PackageReference Include="Newtonsoft.Json" version="13.0.1" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/test/DurableTask.AzureStorage.Tests/DurableTask.AzureStorage.Tests.csproj b/test/DurableTask.AzureStorage.Tests/DurableTask.AzureStorage.Tests.csproj
index 0f133e4ce..71f294b75 100644
--- a/test/DurableTask.AzureStorage.Tests/DurableTask.AzureStorage.Tests.csproj
+++ b/test/DurableTask.AzureStorage.Tests/DurableTask.AzureStorage.Tests.csproj
@@ -16,7 +16,7 @@
   <ItemGroup Condition="'$(TargetFramework)' != 'net462'">
     <PackageReference Include="System.Configuration.ConfigurationManager" Version="4.5.0" />
     <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.6" />
-    <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
     <PackageReference Include="WindowsAzure.Storage" version="9.3.3" />
   </ItemGroup>
 
diff --git a/test/DurableTask.Core.Tests/DurableTask.Core.Tests.csproj b/test/DurableTask.Core.Tests/DurableTask.Core.Tests.csproj
index 061e20f2a..3800b3898 100644
--- a/test/DurableTask.Core.Tests/DurableTask.Core.Tests.csproj
+++ b/test/DurableTask.Core.Tests/DurableTask.Core.Tests.csproj
@@ -18,7 +18,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.9.0" />
     <PackageReference Include="MSTest.TestAdapter" Version="1.4.0" />
     <PackageReference Include="MSTest.TestFramework" Version="1.4.0" />
-    <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/test/DurableTask.Test.Orchestrations/DurableTask.Test.Orchestrations.csproj b/test/DurableTask.Test.Orchestrations/DurableTask.Test.Orchestrations.csproj
index 0e1784357..e2e94505d 100644
--- a/test/DurableTask.Test.Orchestrations/DurableTask.Test.Orchestrations.csproj
+++ b/test/DurableTask.Test.Orchestrations/DurableTask.Test.Orchestrations.csproj
@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
-    <PackageReference Include="Newtonsoft.Json" version="11.0.2" />
+    <PackageReference Include="Newtonsoft.Json" version="13.0.1" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net462'">