diff --git a/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs b/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs
index 5f15fbdc1..d465f0765 100644
--- a/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs
+++ b/src/modules/Elsa.Workflows.Management/Entities/WorkflowDefinition.cs
@@ -12,7 +12,7 @@ public class WorkflowDefinition : VersionedEntity
     /// <summary>
     /// The logical ID of the workflow. This ID is the same across versions. 
     /// </summary>
-    public string DefinitionId { get; set; } = default!;
+    public string DefinitionId { get; set; } = null!;
     
     /// <summary>
     /// The name of the workflow.
@@ -67,17 +67,17 @@ public class WorkflowDefinition : VersionedEntity
     /// <summary>
     /// The name of the workflow materializer to interpret the <see cref="StringData"/> or <see cref="BinaryData"/>.
     /// </summary>
-    public string MaterializerName { get; set; } = default!;
+    public string MaterializerName { get; set; } = null!;
 
     /// <summary>
     /// Provider-specific data.
     /// </summary>
     public string? MaterializerContext { get; set; }
-    
+
     /// <summary>
     /// A textual representation of the workflow. The data is to be interpreted by the configured materializer.
     /// </summary>
-    public string? StringData { get; set; }
+    public string StringData { get; set; } = null!;
     
     /// <summary>
     /// A binary representation of the workflow. The data is to be interpreted by the configured materializer.
diff --git a/src/modules/Elsa.Workflows.Management/Services/WorkflowDefinitionPublisher.cs b/src/modules/Elsa.Workflows.Management/Services/WorkflowDefinitionPublisher.cs
index 75a20e2d4..0cdc9491e 100644
--- a/src/modules/Elsa.Workflows.Management/Services/WorkflowDefinitionPublisher.cs
+++ b/src/modules/Elsa.Workflows.Management/Services/WorkflowDefinitionPublisher.cs
@@ -46,7 +46,7 @@ public class WorkflowDefinitionPublisher : IWorkflowDefinitionPublisher
     }
 
     /// <inheritdoc />
-    public WorkflowDefinition New(IActivity? root = default)
+    public WorkflowDefinition New(IActivity? root = null)
     {
         root ??= new Sequence();
         var id = _identityGenerator.GenerateId();
diff --git a/test/integration/Elsa.Workflows.IntegrationTests/Scenarios/Serialization/Tests.cs b/test/integration/Elsa.Workflows.IntegrationTests/Scenarios/Serialization/Tests.cs
new file mode 100644
index 000000000..786c7a8ba
--- /dev/null
+++ b/test/integration/Elsa.Workflows.IntegrationTests/Scenarios/Serialization/Tests.cs
@@ -0,0 +1,31 @@
+using Elsa.Testing.Shared;
+using Elsa.Workflows.Management;
+using Microsoft.Extensions.DependencyInjection;
+using Xunit.Abstractions;
+
+namespace Elsa.Workflows.IntegrationTests.Scenarios.Serialization;
+
+public class Tests
+{
+    private readonly CapturingTextWriter _capturingTextWriter = new();
+    private readonly IServiceProvider _services;
+    private readonly IWorkflowDefinitionPublisher _publisher;
+    private readonly IActivitySerializer _serializer;
+
+    public Tests(ITestOutputHelper testOutputHelper)
+    {
+        _services = new TestApplicationBuilder(testOutputHelper).WithCapturingTextWriter(_capturingTextWriter).Build();
+        _services.GetRequiredService<IWorkflowBuilderFactory>();
+        _publisher = _services.GetRequiredService<IWorkflowDefinitionPublisher>();
+        _serializer = _services.GetRequiredService<IActivitySerializer>();
+    }
+
+    [Fact(DisplayName = "Can serialize newly created workflow definition")]
+    public async Task Test1()
+    {
+        await _services.PopulateRegistriesAsync();
+        var workflowDefinition = _publisher.New();
+        var root = _serializer.Deserialize(workflowDefinition.StringData);
+        Assert.NotNull(root);
+    }
+}
\ No newline at end of file