Platform upgrade from Azure Functions runtime V2 to V3

In order to keep all elements of the Azure Functions service patched and maintained with security updates moving forward, we will be rolling out a platform upgrade in October 2020 for V2 applications.

For more information on the upgrade, please refer to the GitHub announcement.

Azure Functions V2 apps will be upgraded to run on the V3 runtime. Azure Functions V3 is highly compatible with V2 and the vast majority of apps will be upgraded seamlessly.

Some .NET apps currently running in Azure Functions runtime V2 may be incompatible with V3. For each affected app, you can either choose to opt-out of the platform upgrade, meaning the underlying runtime for your app will continue to run but no longer receive security updates, or make changes to your app to be compatible with the changes.

Upgrading a .NET function app from runtime V2 to V3

Azure Functions V2 apps target .NET Core 2.1 or 2.2, and V3 apps target .NET Core 3.1. If you are using any APIs that have changed in .NET Core 3.1, you will need to make modifications to your app. The steps required to upgrade your application can be found in our documentation.

Opting out of the upgrade (remain on Azure Functions V2)

If you do not upgrade your app to Azure Functions runtime V3, you may “pin” your app to Azure Functions V2.

To pin your app to Azure Functions V2, update the application setting FUNCTIONS_EXTENSION_VERSION to ~2.0.