Can iOS and Android apps (who store user data locally) be updated without losing pre-existing data?

Question

I've seen a number of similar questions posed but for the sake of specificity — is possible to do an update to an existing app without losing the end users existing information?

The scope of the existing app is: - Available on iOS and Android - Stores user data in the app, locally - The app does not require an internet connection at all

The changes to this app would be: - Re-skinning - Fixing technical debt/bugs - Maybe adding some functionality (such as notifications)

If it can be possible to do an update without losing local data, would the original source code be required? (I'm assuming the answer is "DUH")

Unfortunately I can't share the name of this exact (client request).

Thanks!

Answer 1

is possible to do an update to an existing app without losing the end users existing information?

If you are the developer of the original app, yes. Otherwise, no, at least on Android (and I assume that holds true for iOS as well), for obvious security reasons.

would the original source code be required?

Usually, though presumably you are welcome to reimplement the entire app from scratch if you prefer. The bigger thing — again, on Android at least — is that you need the signing key that was used to digitally sign the original application. You can only update the app if the signing key is the same.