Azure Static Web Apps: .NET 8 and .NET 9 end of support

After the end of support date, Azure Static Web Apps managed Functions APIs on .NET 8 or .NET 9 continue to operate, but security updates are no longer provided and support for .NET 8 and .NET 9 on Azure Functions ends. Microsoft states that running apps on an unsupported runtime or language version might lead to security and performance issues. Microsoft also states that the default .NET runtime for Azure Static Web Apps managed Functions APIs is updated to .NET 10 in the same month, and that an explicit apiRuntime setting in staticwebapp.config.json ensures the app builds and runs on the intended runtime. Linked (bring-your-own) Function Apps have a separate deployment lifecycle and must be upgraded and deployed separately.

1. If the API 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.
2. If the API already uses the isolated worker model, follow the C# steps in Update language versions in Azure Functions to target net10.0.
3. 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.
4. Set platform.apiRuntime to dotnet-isolated:10.0 in staticwebapp.config.json. It must describe the same runtime as the API project's TargetFramework.
5. Redeploy the static web app so that the managed API is rebuilt and published on .NET 10. Complete all required upgrades and confirm the API has moved off the in-process model before 10 Nov 2026.
6. Linked (bring-your-own) Function Apps have a separate deployment lifecycle. Upgrade and deploy them separately. Learn more.