iOS New app crashing when starting

I received a 1 star review today from a lady saying she has "yet been able to open the app" and "it has crashed every single time". She appears to be the only one affected. I can understand an error when performing a certain task in the app, but not ever being able to open the app leads me to believe it's an environment issue.

The app uses the 2.1 SDK. Is it possible to install an app on a 2.0 device? This is my current hypothesis. Has anyone else heard of a similar problem as hers?

This is a distribution build and the user downloaded the app from the store. I do restore state when the app loads, similar to the DrillDownSave example from Apple. But there should be no state to load since it's a fresh install.

In addition to my testing before launch, Apple must have tested installing and launching the app as well.