In my iPhone app I\'m caching the raw data of some compressed files to save loading time. But those files may change in an update.
Will iOS clear /Library/Caches for me
It's up to you! Quote from Apple's documentation:
Use this directory to write any application-specific support files that you want to persist between launches of the application or during application updates. Your application is generally responsible for adding and removing these files. It should also be able to re-create these files as needed because iTunes removes them during a full restoration of the device. In iOS 2.2 and later, the contents of this directory are not backed up by iTunes.