Does updating iOS apps delete library directory files?

Question

I keep save files in a private directory in my iPad app, namely the one returned when I use:

paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
documentsDirectory = [paths objectAtIndex:0];
documentsDirectory = [documentsDirectory stringByAppendingPathComponent:@"Private Documents"]; 

Notice that I also append a subdirectory to it. When I update the app, users are telling me that their progress in the app is getting destroyed. Are files in this NSLibraryDirectory destroyed every time I update the app? If so, should I be using NSDocumentDirectory instead?

Additionally, is there no way to make a further update to my app to remedy this without destroying all my my current users' save files? It doesn't seem like there is.

Answer 1

When a user downloads an app update, iTunes installs the update in a new app directory. It then moves the user’s data files from the old installation over to the new app 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.

This is provided by apple officially. See this link : iOS Developer Library - File Saved During App Updates