Implement windows.UpdateTask in WinUI3.0 by registering it in package.appxmanifest file

Hi @Rajendra Rajput ,

I would like to distinguish the specific windows.updateTask deployment task from a regular WinUI 3 background task.

Microsoft documents windows.updateTask as a deployment task that is invoked by the operating system after the package is updated. It does not require a BackgroundTaskBuilder.Register() call. However, declaring the extension alone is not sufficient: its EntryPoint must reference a Windows Runtime component included in the same MSIX package, and that component must implement IBackgroundTask.

For a packaged WinUI 3 application, the closest Microsoft-documented architecture is:

1. Keep the main application as WinUI 3.
2. Add or retain an out-of-process WinRT component that implements IBackgroundTask.
3. Package the component together with the WinUI 3 application in the same MSIX package.
4. Declare the component using the specific windows.updateTask extension in Package.appxmanifest.

<Extension

    Category="windows.updateTask"

    EntryPoint="BackgroundTasks.UpdateTask" />

Therefore, this is not a UWP foreground application combined with a separate WinUI 3 application. It is one WinUI 3 application with an auxiliary WinRT background-task component packaged with it.

If the trigger you registered in code is ServicingComplete, please note that it is not identical to windows.updateTask. A ServicingComplete task must first be registered by running the application. In contrast, Microsoft states that windows.updateTask can be invoked after an update even when the application has never been launched.

For regular Windows App SDK full-trust COM background tasks, the documented model uses Microsoft.Windows.ApplicationModel.Background.BackgroundTaskBuilder, with registration performed in code. Microsoft does not currently document a manifest-only windows.updateTask implementation that uses only a WinUI 3/full-trust COM component.

Microsoft documentation:

• Run a background task when your UWP app is updated
• Background task migration strategy
• Using background tasks in Windows apps

Since Microsoft does not currently provide an end-to-end WinUI 3 sample specifically for windows.updateTask, I recommend validating this architecture with an MSIX update test before relying on it in production.

If you found my response helpful or informative, I would greatly appreciate it if you could provide feedback by interacting with the system or leaving a comment below.

Thank you.

Hi @Rajendra Rajput ,

Following up on my previous comment about the windows.updateTask extension and the WinRT background task component packaged together with your WinUI 3 app. I have not seen an update from you since then, so I would like to check whether the guidance worked on your side.

If I do not hear back by tomorrow, I will post a final summary and close this thread. That does not block you in any way: you can always reply here later, or open a new question, and we will pick it up again.

If the answer resolved your question, please click "Yes" on "Was this answer helpful?" so other developers with the same scenario can find it. If something is still not working, share the details and I am happy to continue supporting you.

Hi Jay,

Referring to your Point No 2. Add or retain an out-of-process WinRT component that implements IBackgroundTask.

WinUI3 does not have WinRT component, are you talking about the WinUI class library here?

And if it is a WinUI class library then it will create just a .dll (Not .winmd file) which needs to be packaged together with the WinUI 3 application in the same MSIX package.

Thanks & Regards,

Rajendra

Hi @Rajendra Rajput ,

Thank you for the clarification. You are correct that a regular WinUI Class Library produces only a managed .dll.

The component I referred to is not a separate UWP foreground application, nor is it a regular WinUI Class Library. For a C# WinUI 3 application on .NET 6 or later, Microsoft documents using C#/WinRT authoring support to create a Windows Runtime Component from a Class Library project. This requires the Microsoft.Windows.CsWinRT package and the following project property:

<PropertyGroup>

  <CsWinRTComponent>true</CsWinRTComponent>

</PropertyGroup>

With this configuration, the build generates the component assembly together with Windows Runtime metadata (.winmd). The component can contain a public sealed class that implements IBackgroundTask, and it can be packaged with the WinUI 3 application in the same MSIX package.

Microsoft documents this approach for out-of-process background tasks in WinUI 3 and other desktop applications:

• Create and register an out-of-process background task
• Create a C#/WinRT Windows Runtime Component

However, I would like to clarify one limitation: the dedicated windows.updateTask documentation is written specifically for UWP, and Microsoft currently does not provide an end-to-end WinUI 3 sample confirming this manifest-only scenario. Therefore, the MSIX update flow should be validated with a minimal test application before relying on it in production.

Since this thread has become quite long and the remaining question now concerns the exact WinUI 3/C#/WinRT project structure and MSIX validation, would you be able to post a new question specifically for that implementation issue? Please share the new question link here, and I will handle it directly and help you work through the project setup and validation.