.NET on Azure Functions – March 2024 roadmap update

(Edit May 2024: We have shared new updates regarding the in-process model option for .NET 8 in the tracking thread on GitHub. Please continue checking there for the most up-to-date status.)

Our last roadmap update was in August 2023, in which we discussed the parity milestone for the isolated worker model and our overall plans for .NET 8. In that post, we outlined a plan to stagger the .NET 8 releases, with support first coming to the isolated worker model, and the in-process model option coming a bit later. This is still the plan, and in this post, we wanted to discuss a bit more about how things will work once the option is available.

How the in-process model option for .NET 8 will work

One key difference between this and previous .NET version changes for the in-process model is that it will be an update solely focused on enabling .NET 8 support. There will be no additional Functions-specific breaking changes from the latest host version for .NET 6 that your project would need to handle. And as we release any fixes or updates to the in-process model for .NET 6, those same updates will be available as part of the in-process model for .NET 8. The only changes you’ll need to make to your project will be to address any system dependencies you may have moving from .NET 6 versions to .NET 8 versions, as you would in any .NET project.

On the function app resource in Azure, you’ll need to change the configuration specifying the .NET version that the system should load, as you normally would. For this new support, you’ll also add a new application setting that acts as an enablement flag.

This means that the expected update process will be to:

1. Update your local version of the Azure Functions Core Tools to latest
2. Change the target framework of your project, and update any system dependencies as needed
3. Test however you normally would
4. Update the function app configuration in Azure to add the app setting and change the .NET version
5. Publish your code changes to the app

The process should therefore be one of the simpler version updates for the in-process model, and it will be a great option for getting to .NET 8 should you not wish to move to the isolated worker model quite yet.

Availability plans

The in-process model option for .NET 8 is a top priority for the Functions team, and we hope to communicate a timeline for release soon. We still expect to give plenty of time to execute the steps outlined above, well in advance of the end of support for .NET 6. If you’re interested in following developments on this, the first place where we’ll signal the availability of the in-process model option for .NET 8 is this tracking thread on GitHub.

Reminders about version support

Per the .NET Official Support Policy, .NET 7 reaches end of support on May 14, 2024, and .NET 6 reaches end of support on November 12, 2024. You’ll want to update any applications targeting those versions to .NET 8 before the end of support. If you’re using .NET 7 on Azure Functions, you’re already using the isolated worker model, and you should update your apps on the isolated worker model to .NET 8. The same instructions apply for .NET 6 on the isolated worker model.

For apps using .NET 6 on the in-process model, your options depend on when you want to migrate to .NET 8. If you were to attempt to migrate at the time of this posting, this would also mean moving to the isolated worker model in the same activity. Many teams have already chosen to do so, but some teams may not be well positioned to perform this migration at this time. The other option is to wait for the in-process model option for .NET 8, which will offer a simpler path to .NET 8.

Planning your migrations

Even if you choose to leverage the in-process option for .NET 8 once it’s available, you should still start planning on a migration to the isolated worker model during the .NET 8 support window. New features will only be added to the isolated worker model, which already provides several advantages over the in-process model.

To help plan these activities, please see the migration guide. And if you encounter any issues with the process or with the isolated worker model itself, please let us know through a migration feedback issue on our GitHub repository.

Closing thoughts

We’re excited to get more apps over to .NET 8, and we appreciate your patience as we make that available for the in-process model. As always, we thank the community for sharing your experiences and helping us make .NET on Azure Functions ever better.

- The Azure Functions team