Which folder will be cleanup when an iOS app has been upgraded

We know that iOS has 开发者_运维问答NSDocumentDirectory, NSCachesDirectory, and NSTemporaryDirectory(), so which folder will be cleanup when an iOS app is upgraded to a newer version? the cache folder, or the temporary folder? and will the temporary folder be cleanup when the app exits?

From docs:

*When a user downloads an application update, iTunes installs the update in a new application directory. It then moves the user’s data files from the old installation over to the new application directory before deleting the old installation. Files in the following directories are guaranteed to be preserved during the update process:

Application_Home/Documents

Application_Home/Library

Although files in other user directories may also be moved over, you should not rely on them being present after an update.*

I recommend you to read The Application Runtime Environment