diff --git a/src/WireMock.Org.Abstractions/MappingsResponse.cs b/src/WireMock.Org.Abstractions/MappingsResponse.cs
index d95b2dd1..e64fc4eb 100644
--- a/src/WireMock.Org.Abstractions/MappingsResponse.cs
+++ b/src/WireMock.Org.Abstractions/MappingsResponse.cs
@@ -62,7 +62,7 @@ namespace WireMock.Org.Abstractions
         /// <summary>
         /// Read-only flag indicating false if this was the default, unmatched response. Not present otherwise.
         /// </summary>
-        public bool FromConfiguredStub { get; set; }
+        public bool? FromConfiguredStub { get; set; }
 
         /// <summary>
         /// The base URL of the target to proxy matching requests to.
diff --git a/src/WireMock.Org.Abstractions/Response.cs b/src/WireMock.Org.Abstractions/Response.cs
index 7f835b33..f0dd9268 100644
--- a/src/WireMock.Org.Abstractions/Response.cs
+++ b/src/WireMock.Org.Abstractions/Response.cs
@@ -62,7 +62,7 @@ namespace WireMock.Org.Abstractions
         /// <summary>
         /// Read-only flag indicating false if this was the default, unmatched response. Not present otherwise.
         /// </summary>
-        public bool FromConfiguredStub { get; set; }
+        public bool? FromConfiguredStub { get; set; }
 
         /// <summary>
         /// The base URL of the target to proxy matching requests to.