Native iPhone App using for non-wp-blog?

Is it possible to use the native iPhone App for a blogging system other then WordPress? This blogging system ‘knows’ metaweblog, movable type, blogger, so I gues it shouldn’t be a problem to blog, since the app uses metaweblog commands.
But when I try to connect, it gives back ‘Sorry, you appear to be running an older version of WordPress that is not supported by this app.’.
Any idea what answer the app wants to receive when connecting?