iOS updating an app in app store - what data survives, what not

[drivefast]

you release an app in the app store. the app stores some preferences (using CFPreferences) and also creates and maintains some files under its own sandboxed "Documents" directory. at one point you create an update of the app and upload it in the app store. when the user updates your app, are the preferences and the files under "Documents" preserved? i've been looking for this in the sdk documents and couldnt find anything related to it.

 

[admanimal]

Technically prefs and the Documents directory should be left alone. In practice this does not always happen and users lose their data.

 

[drivefast]

thanks admanimal. maybe the instability in this area was only present in the early days of the app store, or in the early 2.x versions, and will have to get fixed. is what you're saying documented as such?