My scenario is that I have been developing an iOS app under my personal AppleID and provisioning a bunch of test devices to involve others in the testing. As we are close to rolling out this app, we plan on publishing it using a corporate AppleID. So when the app certificates are be created in the provisioning portal, they will necessarily be under a new AppID.
So the question is: when I rebuild my app with this new AppID and deploy it to existing testers, will they have access to the documents on their device that had been created by the previously-built app? If not, then how do I go about migrating them to the new app without forcing them to re-enter stuff they would have preferred to keep?
check out this basic file system overview
If they are two different app ids, they are two different apps and so cannot access each other’s application home files. You would have needed a cloud based storage solution to facilitate this.
You can also check out this link which has some other options depending on how much data you need to transfer and whether or not you can update the existing app in market before releasing under the new app id.