Retirement: Support for .NET 8 and .NET 9 on Static Web Apps is ending November 10, 2026

Support for .NET 8 and .NET 9 will end on November 10, 2026. Please transition your managed Functions APIs to .NET 10 by that date. 

Your apps will continue to operate, but security updates will no longer be provided and support for .NET 8 and .NET 9 on Azure Functions will end. Running apps on an unsupported runtime or language version might lead to security and performance issues. 

Upgrade to .NET 10 before November 10, 2026 to remain on a supported version. Learn more about the .NET support policy and the Azure Functions language support policy. 

Recommended action 

To avoid potential security vulnerabilities, minimize risk for your Azure Static Web Apps managed Functions APIs, and take advantage of the latest features, act based on your current configuration. 

If your API currently uses the in-process model  

Follow the .NET 10 steps in Migrate C# apps from the in-process model to the isolated worker model to update the API project, packages, startup code, function code, and configuration for the isolated worker model.  

If your API is already using the isolated worker model  

Follow the C# steps in Update language versions in Azure Functions to update the API project to target net10.0.  

For both configurations  

1. Confirm that the API project targets net10.0, and update the Functions SDK and worker packages to meet the .NET 10 isolated worker project and package requirements. Build and test the API locally before continuing.  
   

1. Set the API runtime in staticwebapp.config.json:   

{
  "platform": {
    "apiRuntime": "dotnet-isolated:10.0"
  }
}  

The API project's TargetFramework and the platform.apiRuntime value in staticwebapp.config.json must describe the same runtime. 

1. Redeploy your static web app so Azure Static Web Apps rebuilds and publishes the managed API on .NET 10. 
   

Complete all required upgrades and ensure your API has moved off the in-process model before November 10, 2026.  

Upcoming change  

In November 2026, the default .NET runtime for Azure Static Web Apps managed Functions APIs will be updated to .NET 10. The explicit apiRuntime setting in the steps above ensures your app builds and runs on the intended runtime. See Supported languages and runtimes in Azure Static Web Apps.  

Linked (bring-your-own) Function Apps have a separate deployment lifecycle and must be upgraded and deployed separately.  

Learn more.