With the in-process programming model and Azure Functions 4.0, you can write .NET 6 function apps that take advantage of advanced features such as Durable Functions. See the documentation to learn more:
.NET 6 is also supported in Azure Functions 4.0 using the isolated process programming model. The isolated model gives you full control over the language worker startup configuration and provides useful features like dependency injection and middleware. Currently, you can use the command line to create and deploy your .NET 6 isolated apps. .NET 6 isolated process support is coming soon to Visual Studio and Visual Studio Code.
While the new runtime is currently in preview, you won't have to wait long to run .NET 6 function apps in production. Azure Functions 4.0 is expected to be generally available when .NET 6 LTS is released in early November.
Migrating your apps to Azure Functions 4.0 preview
The Azure Functions host and language workers will continue to evolve during the preview period. There's a list of planned breaking changes. You'll also want to make sure to subscribe to App Service Announcements for notifications on breaking changes and how to mitigate them.
September 22, 2021 22:41UTC – Added "Staying up-to-date" section
November 16, 2021 23:00UTC – Adding link to GA announcement