Azure Functions: Avoid unstable runtime version references

[fabiocav]

Note: this announcement is a reminder for announcements made in 2017 (#34) and 2018 (#135)

We have identified a small number of customers with incorrectly configured Azure Functions 2.0 Apps. Those Function Apps are using an unstable version reference by specifying the FUNCTIONS_EXTENSION_VERSION value of latest, which may lead to unintended adoption of new, potentially breaking, functionality.

We are taking action to update configuration where possible, but user action is required to ensure no further deployments (the impacted applications are typically deployed using ARM templates using an outdated configuration) apply that configuration value.

In the coming days, latest will start redirecting to a new version that may introduce compatibility issues for customers using this version reference.

Take Action

Function Apps use the FUNCTIONS_EXTENSION_VERSION app setting to control which version of functions the app runs on. A V2 Function App should have this setting set to ~2.

You can find this information using the Azure Functions portal (under Function App Settings).

An incorrectly configured Function App will have the following information (with latest as the referenced version):

If that is the case for your application, please take action by clicking on the ~2 button.

The site configuration should look like this:

ARM Template Deployments

If you deploy your application using ARM templates, please ensure your templates are updated to reference ~2 for the FUNCTIONS_EXTENSION_VERSION app setting.