title: Cannot Upgrade with Existing Functions
body: <p>Create a new Azure Function App from the Azure Portal.  Add a new function to it. You will be presented with a warning icon with the following text:</p>
  
  <blockquote>
    <h2>Cannot Upgrade with Existing Functions</h2>
    
    <p>Major version upgrades can introduce breaking changes to languages and bindings. When upgrading major versions of the runtime, consider creating a new function app and migrate your functions to this new app.</p>
  </blockquote>
  
  <p>My question is what action is required?  Is it simply a warning that a future upgrade might cause issues? Perhaps is it related to <a href="https://github.com/Azure/Azure-Functions/issues/640" rel="nofollow noreferrer">the GitHub commentary about new template versions in Visual Studio</a> </p>
  
  <p>Note: deleting the all functions from the function app, causes the issue to disappear.</p>