Android versioned updater

We are delivering an application to customers that they can install at their own server. We also have an android client wich communicates with the server over hessian. The problem width puttng that app in android market is that the interface can be different from the server if the client does not upgrade their server. The project is to write a simple andoid application that acts as a wrapper. it should save one setting and that is the adress of the server to check the version of. Get the version of the server, Next if not installed download the correct version of the Client app. Launch the application. It very understandable and a common problem. We figure there are people that have build this or know how to do this. Message to the end user are considered acceptable.