Update custom-deserializer.md

added retirement

Author: enkrumah

articles/stream-analytics/custom-deserializer.md

@@ -6,11 +6,14 @@ ms.author: anboisve
 ms.service: stream-analytics
 ms.custom: devx-track-dotnet
 ms.topic: tutorial
-ms.date: 01/12/2023
+ms.date: 02/26/2024
 ---
 
 # Custom .NET deserializers for Azure Stream Analytics in Visual Studio (Preview)
 
+> [!IMPORTANT]
+> Custom .net deserializer for Azure Stream Analytics will be retired on 30th September 2024. After that date, it won't be possible to use the feature. Please transition to a [JSON, AVRO, or CSV built-in deserializer](./stream-analytics-parsing-json.md) by that date.
+
 Azure Stream Analytics has [built-in support for three data formats](stream-analytics-parsing-json.md): JSON, CSV, and Avro. With custom .NET deserializers, you can read data from other formats such as [Protocol Buffer](https://developers.google.com/protocol-buffers/), [Bond](https://github.com/Microsoft/bond) and other user defined formats for both cloud and edge jobs.
 
 This tutorial demonstrates how to create a custom .NET deserializer for an Azure Stream Analytics cloud job using Visual Studio. To learn how to create .NET deserializers in Visual Studio Code, see [Create .NET deserializers for Azure Stream Analytics jobs in Visual Studio Code](visual-studio-code-custom-deserializer.md).