From 136e7b9d80273033f9aa6c939c63a9ab172f4d52 Mon Sep 17 00:00:00 2001
From: Quinn Tracy <142489060+quinntracy@users.noreply.github.com>
Date: Thu, 3 Sep 2026 10:55:33 +0200
Subject: [PATCH] Add C# Extensibility warning box

---
 .../apidocs/studio-pro-10/extensibility-api/csharp/_index.md  | 4 ++--
 .../csharp/extensibility-api-howtos/add-menu.md               | 4 ++++
 .../extensibility-api-howtos/build-todo-example-extension.md  | 4 ++++
 .../csharp/extensibility-api-howtos/create-context-menu.md    | 4 ++++
 .../csharp/extensibility-api-howtos/create-dockable-pane.md   | 4 ++++
 .../csharp/extensibility-api-howtos/create-menu-extension.md  | 4 ++++
 .../extensibility-api-howtos/create-microflow-service.md      | 4 ++++
 .../create-microflows-calculations.md                         | 4 ++++
 .../csharp/extensibility-api-howtos/create-modal-web-view.md  | 4 ++++
 .../csharp/extensibility-api-howtos/export-an-extension.md    | 4 ++++
 .../extensibility-api-howtos/interact-with-model-api.md       | 4 ++++
 .../csharp/extensibility-api-howtos/untyped-model-api.md      | 4 ++++
 .../extensibility-api-reference-guide/extension-points.md     | 4 ++++
 .../csharp/extensibility-api-reference-guide/services.md      | 4 ++++
 .../csharp/extensibility-api-reference-guide/web-view.md      | 4 ++++
 .../studio-pro-10/extensibility-api/csharp/get-started.md     | 4 ++++
 .../apidocs/studio-pro-11/extensibility-api/csharp/_index.md  | 4 ++--
 .../csharp/extensibility-api-howtos/add-menu.md               | 4 ++++
 .../extensibility-api-howtos/build-todo-example-extension.md  | 4 ++++
 .../csharp/extensibility-api-howtos/create-context-menu.md    | 4 ++++
 .../csharp/extensibility-api-howtos/create-dockable-pane.md   | 4 ++++
 .../csharp/extensibility-api-howtos/create-menu-extension.md  | 4 ++++
 .../extensibility-api-howtos/create-microflow-service.md      | 4 ++++
 .../create-microflows-calculations.md                         | 4 ++++
 .../csharp/extensibility-api-howtos/create-modal-web-view.md  | 4 ++++
 .../csharp/extensibility-api-howtos/export-an-extension.md    | 4 ++++
 .../extensibility-api-howtos/interact-with-model-api.md       | 4 ++++
 .../csharp/extensibility-api-howtos/untyped-model-api.md      | 4 ++++
 .../extensibility-api-reference-guide/extension-points.md     | 4 ++++
 .../csharp/extensibility-api-reference-guide/services.md      | 4 ++++
 .../csharp/extensibility-api-reference-guide/web-view.md      | 4 ++++
 .../studio-pro-11/extensibility-api/csharp/get-started.md     | 4 ++++
 32 files changed, 124 insertions(+), 4 deletions(-)

diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/_index.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/_index.md
index cab3a4c55ab..54f3589c887 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/_index.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/_index.md
@@ -12,8 +12,8 @@ aliases:
 This feature is in beta. For more information, see [Release Status](/releasenotes/release-status/).
 {{% /alert %}}
 
-{{% alert color="info" %}}
-For information on new releases of the Extensibility API, see [Extensibility: C# API Release Notes](/releasenotes/studio-pro/csharp-extensibility-api/).
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
 {{% /alert %}}
 
 ## Introduction
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/add-menu.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/add-menu.md
index 3362f4abefc..8877ae9a127 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/add-menu.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/add-menu.md
@@ -7,6 +7,10 @@ weight: 15
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 This how-to describes how to add a menu that contains sub-menus, some of which also contain sub-menus of their own. 
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md
index 4322aec8249..7faea939cc6 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md
@@ -7,6 +7,10 @@ weight: 20
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 This document describes how to build a simple to-do list extension for Studio Pro.
 
 The extension allows you to add new to-do items to a list, which integrate with Studio Pro's main menu. You will also create a user interface for the extension using a dockable pane and web content.
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md
index 0a2e573e443..5e19a1f4c0b 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md
@@ -7,6 +7,10 @@ weight: 6
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 You can add a context menu to an `IEntity` in Studio Pro or to a `IDocument`, such as microflows and pages. These context menus will appear under a menu named after the extension that contains them (for example, `MyExtension`) and can modify the items they relate to. This is achieved by specifying the type when creating the extension.
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md
index b9fe87b390d..32f478128ab 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md
@@ -7,6 +7,10 @@ weight: 5
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 This how-to describes how to add a custom dockable web pane window to Studio Pro. 
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md
index 76a420b77ef..b0e1ee8dded 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md
@@ -7,6 +7,10 @@ weight: 4
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 This how-to describes how to create an extension that adds an item to Studio Pro menu from scratch.
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md
index 7bac2affcae..efd9b7b1fdd 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md
@@ -7,6 +7,10 @@ weight: 14
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
  This how-to describes how to create a new microflow and add activities to it. The `IMicroflowService` is used to perform actions related to microflows.
 
 ## Creating and Initializing a Microflow Using `Initialize`
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md
index d4c263157ee..2e6912dada3 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md
@@ -7,6 +7,10 @@ weight: 8
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 This how-to describes how to create microflows that perform calculations and return the result.
 
 You can download the example in this how-to from [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md
index b8225e8c1ac..059246cad55 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md
@@ -7,6 +7,10 @@ weight: 7
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 This how-to describes how to create a new web view hosted inside a modal dialog, and how to open the modal from a new menu item.
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples)
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md
index 411dc96ea28..f3b5aa5a8c3 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md
@@ -7,6 +7,10 @@ weight: 99
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 This how-to describes how to export an extension so you can publish it in the Marketplace or share it directly with other Mendix developers.
 
 ## Prerequisites
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md
index 6a6f21de9c8..d01876114af 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md
@@ -7,6 +7,10 @@ weight: 11
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 Once you have created basic extensions, you may want to interact with the Studio Pro model to make changes to your app. The Model API enables this functionality and is exposed via the`Mendix.StudioPro.ExtensionsAPI.Model` namespace.
 
 ## Gaining Access to the Mendix Model SDK
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md
index c4e4fa2d639..183bcdd5a3b 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md
@@ -7,6 +7,10 @@ weight: 24
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 The Untyped Model Access API is designed for advanced users familiar with the internals of the Mendix platform. It allows access to the rich data of model elements.
 
 * For model elements, units, and property names, see the [Mendix Model SDK](https://apidocs.rnd.mendix.com/modelsdk/latest/index.html). 
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md
index b4f89b2518f..8f9daf5cad5 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md
@@ -7,6 +7,10 @@ weight: 9
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 Extension points allow you to hook functionality into various areas of the Studio Pro IDE. `ExtensionPoint` is a base class that extension developers can inherit from. Once inherited, your functionality will be loaded by Studio Pro. These classes all have the `*Extension` suffix, inherit from the [`ExtensionBase`](https://github.com/mendix/ExtensionAPI-Samples/blob/main/API%20Reference/Mendix.StudioPro.ExtensionsAPI/ExtensionBase.md) base class, and contain a few virtual or abstract members.
 
 `ExtensionPoint` is the only way you can add a custom behavior to Studio Pro. All other APIs provided solely to support the implementation or expression of these behaviors.
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/services.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/services.md
index 9387125047b..5cc49909a4b 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/services.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/services.md
@@ -7,6 +7,10 @@ weight: 10
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 A Studio Pro service is an interface that exposes some core Studio Pro functionality to extensions. These interfaces are named `I*Service` and can be found in `Mendix.StudioPro.ExtensionsAPI.Services` or `Mendix.StudioPro.ExtensionsAPI.UI.Services` namespaces. It can be injected using the Microsoft Extensions Framework, also referred to as MEF. For more information about MEF and how to use it, refer to the official [Microsoft documentation](https://learn.microsoft.com/en-us/dotnet/framework/mef/).
 
 {{% alert color="info" %}}You should not implement these interfaces in your production code, although it is possible to make sense to do so for unit testing purposes.{{% /alert %}}
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md
index 01cfa7ab2ad..64a871f4d51 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md
@@ -7,6 +7,10 @@ weight: 12
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 Wherever the Studio Pro Extensibility API allows you to add custom UI, you can implement it using web technologies.
 
 Studio Pro includes a built-in web view for displaying your web-based UI. It also provides a built-in web server that can be used to serve both the web UI and the data it requires.
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/get-started.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/get-started.md
index 3876f4ee2dd..a47afe3c82a 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/get-started.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-10/extensibility-api/csharp/get-started.md
@@ -9,6 +9,10 @@ weight: 2
 
 This document describes how to set up a basic development environment for building extensions.
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-10/) instead.
+{{% /alert %}}
+
 ## Development Setup
 
 {{% alert color="info" %}}
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/_index.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/_index.md
index edd73c4c4a7..c1079273b65 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/_index.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/_index.md
@@ -12,8 +12,8 @@ aliases:
 This feature is in beta. For more information, see [Release Status](/releasenotes/release-status/).
 {{% /alert %}}
 
-{{% alert color="info" %}}
-For information on new releases of the Extensibility API, see [Extensibility: C# API Release Notes](/releasenotes/studio-pro/csharp-extensibility-api/).
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
 {{% /alert %}}
 
 ## Introduction
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/add-menu.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/add-menu.md
index 0af69755116..a6c963b0a81 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/add-menu.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/add-menu.md
@@ -7,6 +7,10 @@ weight: 15
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 This how-to describes how to add a menu that contains sub-menus, some of which also contain sub-menus of their own. 
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md
index 8dfa7fdddad..1326992b01b 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/build-todo-example-extension.md
@@ -7,6 +7,10 @@ weight: 20
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 This document describes how to build a simple to-do list extension for Studio Pro. 
 
 The extension allows you to add new to-do items to a list, which integrate with Studio Pro's main menu. You will also create a user interface for the extension using a dockable pane and web content. 
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md
index 60d03d1bb0a..5aaf0a26d8c 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-context-menu.md
@@ -7,6 +7,10 @@ weight: 6
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 You can add a context menu to an `IEntity` in Studio Pro or to a `IDocument`, such as microflows and pages. These context menus will appear under a menu named after the extension that contains them (for example, `MyExtension`) and can modify the items they relate to. This is achieved by specifying the type when creating the extension.
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md
index 1b4b837427c..a67c60c9879 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-dockable-pane.md
@@ -7,6 +7,10 @@ weight: 5
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 This how-to describes how to add a custom dockable web pane window to Studio Pro. 
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md
index a6ff0900480..f13d2dafd15 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-menu-extension.md
@@ -7,6 +7,10 @@ weight: 4
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 This how-to describes how to create an extension that adds an item to Studio Pro menu from scratch.
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md
index 56d3247d6a2..a445b4077ac 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflow-service.md
@@ -7,6 +7,10 @@ weight: 14
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
  This how-to describes how to create a new microflow and add activities to it. The `IMicroflowService` is used to perform actions related to microflows.
 
 ## Creating and Initializing a Microflow Using `Initialize`
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md
index 5cead61ed41..394cba70ebe 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-microflows-calculations.md
@@ -7,6 +7,10 @@ weight: 8
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 This how-to describes how to create microflows that perform calculations and return the result.
 
 You can download the example in this how-to from [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md
index 682baf0f877..18ea218dbd8 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/create-modal-web-view.md
@@ -7,6 +7,10 @@ weight: 7
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 This how-to describes how to create a new web view hosted inside a modal dialog, and how to open the modal from a new menu item.
 
 You can download the example in this how-to in [this GitHub repository](https://github.com/mendix/ExtensionAPI-Samples)
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md
index e2746b7d9ca..1fc575d9fca 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/export-an-extension.md
@@ -7,6 +7,10 @@ weight: 99
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 This how-to describes how to export an extension so you can publish it in the Marketplace or share it directly with other Mendix developers.
 
 ## Prerequisites
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md
index 6e465471466..e37b70dd294 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/interact-with-model-api.md
@@ -7,6 +7,10 @@ weight: 11
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 Once you have created basic extensions, you may want to interact with the Studio Pro model to make changes to your app. The Model API enables this functionality and is exposed via the `Mendix.StudioPro.ExtensionsAPI.Model` namespace.
 
 ## Gaining Access to the Mendix Model SDK
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md
index 6d2b654bd85..ccb5edba399 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-howtos/untyped-model-api.md
@@ -7,6 +7,10 @@ weight: 24
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 The Untyped Model Access API is designed for advanced users familiar with the internals of the Mendix platform. It allows access to the rich data of model elements.
 
 * For model elements, units, and property names, see the [Mendix Model SDK](https://apidocs.rnd.mendix.com/modelsdk/latest/index.html).
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md
index b3fb7488bee..39c07ccd5bb 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/extension-points.md
@@ -7,6 +7,10 @@ weight: 9
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 Extension points allow you to hook functionality into various areas of the Studio Pro IDE. `ExtensionPoint` is a base class that extension developers can inherit from. Once inherited, your functionality will be loaded by Studio Pro. These classes all have the `*Extension` suffix, inherit from the [`ExtensionBase`](https://github.com/mendix/ExtensionAPI-Samples/blob/main/API%20Reference/Mendix.StudioPro.ExtensionsAPI/ExtensionBase.md) base class, and include a few virtual or abstract members.
 
 `ExtensionPoint` is the only way to add custom behavior to Studio Pro. All other APIs provided solely to support the implementation or expression of these behaviors.
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/services.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/services.md
index 97c6269ecfc..77897520ec3 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/services.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/services.md
@@ -7,6 +7,10 @@ weight: 10
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 A Studio Pro service is an interface that exposes some core Studio Pro functionality to extensions. These interfaces are named `I*Service` and can be found in `Mendix.StudioPro.ExtensionsAPI.Services` or `Mendix.StudioPro.ExtensionsAPI.UI.Services` namespaces. It can be injected using the Microsoft Extensions Framework, also referred to as MEF. For more information about MEF and how to use it, refer to the official [Microsoft documentation](https://learn.microsoft.com/en-us/dotnet/framework/mef/)
 
 {{% alert color="info" %}}You should not implement these interfaces in your production code, although it is possible to make sense to do so for unit testing purposes.{{% /alert %}}
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md
index 19473649c07..de980762474 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/extensibility-api-reference-guide/web-view.md
@@ -7,6 +7,10 @@ weight: 12
 
 ## Introduction
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 Wherever the Studio Pro Extensibility API allows you to add custom UI, you can implement it using web technologies.
 
 Studio Pro includes a built-in web view for displaying your web-based UI. It also provides a built-in web server that can be used to serve both the web UI and the data it requires.
diff --git a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/get-started.md b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/get-started.md
index 6f519c989e6..196f7a0b21e 100644
--- a/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/get-started.md
+++ b/content/en/docs/apidocs-mxsdk/apidocs/studio-pro-11/extensibility-api/csharp/get-started.md
@@ -9,6 +9,10 @@ weight: 2
 
 This document describes how to set up a basic development environment for building extensions.
 
+{{% alert color="warning" %}}
+C# Extensibility is no longer being actively developed and will receive only critical fixes going forward. For new, modern extensions, use the TypeScript [Web Extensibility APIs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/) instead.
+{{% /alert %}}
+
 ## Development Setup
 
 {{% alert color="info" %}}