IOS: save a csv o txt file when I delete an app

I'm creating an app and when a person use this app, lot informations are recorded in a txt file; If I want to make changes at this app, I must delete app from device. Then, how can I save the txt file before I delete the application? Is there a way to 开发者_开发技巧do this?

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Instead of deleting the app to make changes, install an updated app with the old app in place to preverve the content of the Documents folder (NSDocumentDirectory).

You could also save the data in the cloud whenever the app exits.