What happens to old app data written in another language when you release a new version of the App written in Flutter?

Question

So I have my app released which was written in another older framework (non flutter).

I've since rewritten the app from scratch in Flutter. The app, while functionally about the same, its a total rewrite, including the way data is stored and images are stored, using flutter packages.

Now I want to release my shiny new app written in flutter, as a version update. Before it was version 2.0, now the flutter version will be 3.0.

But I'm wondering what happens to all the stored data from the old App. I'm wondering if it gets orphaned somewhere as it is not really accessible by the Flutter version of the app as the upgrade happens?

If that is really what happens, is there anything that can be done to clear all that data before this new flutter version is installed?

Ideally I would want users to delete the old app before installing this new version, but realistically, people won't do that. They will just update from the play/app store and not think twice about it and just think the app was reskinned.

This app change will be happening for both Android and iOS. Incase there are differences between the two platforms pertaining to these questions

Thanks!

Answer 1

When the new (flutter) version of the app runs, just look for the directories / files where the old data was stored. If they exist, delete them.