iOS - updating user flow without app update

I'm looking at designing and building out a system that would allow A/B testing of different f开发者_运维知识库lows in an iOS app (e.g. registration flow, log-in flow, purchasing flow).

A system that comes to mind initially looks like:

1. app pings server, server responds giving list of resources (which could include some links to xib files)
2. if the user does not have those xibs on disk, download them and save them to disk
3. when the view controller is presented, load from the xib if it has been downloaded (else default to the one the app was shipped with)

Does anyone have any thoughts on this idea or any insights on this system?

NOTE: I am not trying to implement a system where I can add new features. Right now, I'm focusing on changing flows, like the text and views a user will see. I'm not looking into a discussion of whether this violates the App Store rules, but if you would like to do so - go for it!

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This is possible, but I don't know if I would download XIBs to the device. Seems a little risky to me.

Apple did a talk at WWDC 2010 where they address this exact issue, and they recommend building the interface using (more or less) Plists or JSON to describe the UI elements and their functions, and building up the views dynamically. It's well worth watching as it brings up a lot of smaller issues that aren't immediately obvious, but it requires a developer account to access it).

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This would be an interesting system to use. I wonder if one could write a shell script to replace the old binary of an app with a new one. I know it would probably be more complicated then just that, but it would be cool to do. I would definitely use this for in house apps, or personal tools. Its to bad the apple wouldn't allow it, unless someone could secretly slip it past them :-)

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I say go for it. You seem to have a pretty good idea of what you want to do and how you want to do it. Changing the UI based on responses from a server isn't uncommon, but I guess downloading xib files from the server is. I don't see why it wouldn't work though and I don't think it would be rejected by Apple, but you never know.