iOS My App Update is crashing downloaders, any tips?

So here's the deal, I am reposting because I figure this might be a little more clear.

I recently released a v1.1 of my software. When installed direct, it works fine. But when installed as an update to v1.0 through the app store, it seems to crash quite a few people.

When they uninstall completely, and then re-install...they seem to be fine.

Is there a way to setup my app to completely uninstall or erase any remnants of the previous installation? My worry is there is something in there that doesn't get erased, causing the crashes.

Hard to debug!

Thanks!

Basem