The following applies miserably:
Files Saved During App Updates
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:
Although files in other user directories may also be moved over, you should not rely on them being present after an update.
So basically, use relative paths, instead of absolute ones.