Hopefully a easy(-ish) one, but I'm just wondering if it's possible to update an ad-hoc over-the-air installed iOS app (deployed using the standard $99 developer license), hence ensuring that any data stored within the app's document sandbox is still available.
Additionally if iOS 4.x file protection is used (i.e.: the NSFileProtectionComplete encrypt attribute is set on the files, etc.) will an updated app still be able to read the files?
Whilst there are some existing questions that touch on this (such as Updating enterprise iOS apps while retaining some files of the current app bundle), these don't answer this specific query and (potentially) pre-date the newer style of ad-hoc distribution.
You can definitely update an ad hoc over-the-air-installed iOS app and retain the current app data -- it appears to work identically to normal update installation.
Because it works the same way as a normal update, file protection should work the same as well, though I don't have first-hand experience.