diff --git a/uSync.Core/Extensions/JsonTextExtensions.cs b/uSync.Core/Extensions/JsonTextExtensions.cs
index 8f8a04129..b67e1d01c 100644
--- a/uSync.Core/Extensions/JsonTextExtensions.cs
+++ b/uSync.Core/Extensions/JsonTextExtensions.cs
@@ -31,6 +31,8 @@ public static class JsonTextExtensions
             new JsonUdiRangeConverter(),
             new JsonBooleanConverter(),
             new JsonXElementConverter(),
+            new JsonBlockListLayoutItemConverter(),
+            new JsonBlockGridLayoutItemConverter()
         }
     };
 
diff --git a/uSync.Core/Json/JsonBlockItemConverters.cs b/uSync.Core/Json/JsonBlockItemConverters.cs
new file mode 100644
index 000000000..529b65d87
--- /dev/null
+++ b/uSync.Core/Json/JsonBlockItemConverters.cs
@@ -0,0 +1,78 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+using Umbraco.Cms.Core.Models.Blocks;
+
+namespace uSync.Core.Json;
+
+/// <summary>
+/// in v16 the BlockLayoutItem(s) have obsolete properties that are sometimes set and sometimes not
+/// this leads to false positive's when looking for changes. 
+/// 
+///  these two custom converters write those properties out as null, so they never change. causing
+///  the serialized json to be consistent. 
+/// </summary>
+
+public abstract class JsonBlockItemConverterBase<T> : JsonConverter<T>
+    where T : BlockLayoutItemBase, new()
+{
+    public override T? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        if (reader.TokenType != JsonTokenType.StartObject)
+            throw new JsonException("Invalid JSON expecting start object");
+
+        var item = new T();
+
+        while (reader.Read())
+        {
+            if (reader.TokenType == JsonTokenType.EndObject)
+                return item;
+
+            if (reader.TokenType != JsonTokenType.PropertyName)
+                throw new JsonException("Expecting property name");
+
+            var propertyName = reader.GetString();
+            reader.Read();
+
+            switch (propertyName)
+            {
+                case "contentKey":
+                    var contentKey = reader.GetString();
+                    if (contentKey != null && Guid.TryParse(contentKey, out var contentGuid))
+                        item.ContentKey = contentGuid;
+                    break;
+                case "settingsKey":
+                    var settingsKey = reader.GetString();
+                    if (settingsKey != null && Guid.TryParse(settingsKey, out var settingsGuid))
+                        item.SettingsKey = settingsGuid;
+                    break;
+                default:
+                    // we don't care about the obsolete properties here...
+                    break;
+            }
+        }
+
+        throw new JsonException("Unexpected end of JSON");
+    }
+
+    public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
+    {
+        // we could just not write out the obsolete properties, but they will appear as null it 
+        // lots of people's existing exports , so we can write them out as null to keep things consistent.
+        writer.WriteStartObject();
+        writer.WriteString("contentKey", value.ContentKey.ToString());
+        writer.WriteNull("contentUdi");
+
+        if (value.SettingsKey.HasValue && value.SettingsKey != Guid.Empty)
+            writer.WriteString("settingsKey", value.SettingsKey.ToString());
+        else
+            writer.WriteNull("settingsKey");
+
+        writer.WriteNull("settingsUdi");
+        writer.WriteEndObject();
+    }
+}
+
+public class JsonBlockListLayoutItemConverter : JsonBlockItemConverterBase<BlockListLayoutItem> { }
+
+public class JsonBlockGridLayoutItemConverter : JsonBlockItemConverterBase<BlockGridLayoutItem> { }
diff --git a/uSync.Core/Json/XElementJsonConverter.cs b/uSync.Core/Json/XElementJsonConverter.cs
index 22b2a392b..23959e33e 100644
--- a/uSync.Core/Json/XElementJsonConverter.cs
+++ b/uSync.Core/Json/XElementJsonConverter.cs
@@ -16,3 +16,4 @@ public override void Write(Utf8JsonWriter writer, XElement value, JsonSerializer
         writer.WriteStringValue(value.ToString());
     }
 }
+