add deprecation for template gallery

Author: tfitzmac

articles/azure-resource-manager/templates/template-spec-convert.md

@@ -2,7 +2,7 @@
 title: Convert portal template to template spec
 description: Describes how to convert an existing template in the Azure portal gallery to a template specs.
 ms.topic: conceptual
-ms.date: 02/04/2021
+ms.date: 05/25/2022
 ms.author: tomfitz
 author: tfitzmac
 ---
@@ -12,6 +12,10 @@ The Azure portal provides a way to store Azure Resource Manager templates (ARM t
 
 To see if you have any templates to convert, view the [template gallery in the portal](https://portal.azure.com/#blade/HubsExtension/BrowseResourceBlade/resourceType/Microsoft.Gallery%2Fmyareas%2Fgalleryitems). These templates have the resource type `Microsoft.Gallery/myareas/galleryitems`.
 
+## Deprecation of portal feature
+
+**The template gallery in the portal is being deprecated on March 31, 2025**. To continue using a template in the template gallery, you need to migrate it to a template spec. Use one of the methods shown in this article to migrate the template.
+
 ## Convert with PowerShell script
 
 To simplify converting templates in the template gallery, use a PowerShell script from the Azure Quickstart Templates repo. When you run the script, you can either create a new template spec for each template or download a template that creates the template spec. The script doesn't delete the template from the template gallery.