iPhone prompt to update
===

I am currently working on an API for an iPhone app, which is for the version 2 of the app.
(APIs were developed in Padrino)

So I still have the old API for version 1 iPhone app.

What I wanted to do is to prompt the iPhone app user (if possible) to download the latest version of the app and iPhone user will not be able to access the iPhone app version 1 anymore.

any inputs will be appreciated.

thanks!