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.