title: Is it possible to upgrade a Heroku app's buildpack after the app has been created?
body: <p>I have an existing node.js app on heroku and I want to upgrade the node.js version by supplying a 0.6.7 buildpack. </p>
  
  <p>Is it possible to update the buildpack a Heroku app is assigned?</p>
  
  <p>If not, what is the suggested path for upgrading the builpack an app uses? </p>
  
  <p>If I have to deploy a new app, how do I made sure the addons don't die?</p>
  
  <p>Thanks,</p>
  
  <p>Matt</p>