My game uses cocos2d-x and will be published on iOS platform first, later on Android. I save a lot of things with CCUserDefault (scores, which level was completed, number of coins taken, etc...). But now I have a big doubt.

What will happen when the game will receive its first update?

CCUserDefault uses an XML file stored somewhere in the app storage space. This file is created and retained until one uninstalls the app. I am wondering what happens when the app is updated. Will the old XML file be maintained?

Because if not, how should I handle app updates (updates in the sense that 2, 3 or more new level packages will be added, but the informations about the old ones, like scores, which level was finished and which not, number of coins, etc., need absolutely not to be lost)?