I'm working on an iPhone app and about to release version 2. We'll be changing the core data model and I'd like to simulate the upgrade process in the simulator before releasing it to users and potentially causing data loss for them. There doesn't seem to be any real good doucumentation on how to do this in a sandbox before releasing it.
The process I've used in the past has been to wipe any working version from the Simulator, check out the previous version of my application from my repository, compile and install that, work with it for a bit, then compile and install the new version of the application. The installation of the new version should simulate the upgrade process, where you can test your data migration to your new model.
I also repeat this process on the device to make sure no problems are encountered there either.
there are some cases that cannot be simulated in Xcode. Look at this Apple page: https://developer.apple.com/library/ios/technotes/tn2285/_index.html
You have to create IPA file and simulate update via iTunes.
I agree with Brad's overall approach. To save a little time, I would just save the sample set of data that you create with the older version of your app. This way you won't have to keep recreating the sample data set if things don't go right. You will just simply copy the sample data set back into your app's directory in the Simulator.
Your app's directory is located at ~/Library/Application Support/iPhone Simulator/User/Applications/A GUID for your App on your development machine.
来源：https://stackoverflow.com/questions/2375807/how-can-simulate-the-iphone-app-upgrade-process-in-the-sdk-simulator