The node.js buildpack has good instructions for how to upgrade it yourself if needed: https://github.com/heroku/heroku-buildpack-nodejs (and the buildpack docs are now public since Heroku's Cedar stack became the official default)
I meant when will they update it so that you can use the new version of Node without hacking the buildpack.
>To change the vendored binaries for Node.js, NPM, and SCons, use the helper scripts in the support/ subdirectory. You'll need an S3-enabled AWS account and a bucket to store your binaries in.
I don't want to mess with that, I'd rather wait for Heroku to update so I can change one line in my package.json.
I'm beginning to wonder if Heroku is going to bother with this any time soon. The default version is _still_ 0.4.7 [1] and personally I'm starting to feel the pressure to update, especially considering recent performance improvements.