Если все сохранять в локальную пользовательскую директорию Documents - то она бэкапится в iCloud и сохраняется после обновления приложения.
system.DocumentsDirectory: This directory is intended for files that the app cannot regenerate on its own, for example user-specific data, "app state" data, or anything that the app generates post-installation. Files in this directory will persist for the lifetime of the app — that is, until the app is explicitly removed from the device. On iOS, files in this location are backed up by syncing unless you specify otherwise.
https://docs.coronalabs.com/api/library/system/Doc...