Downloaded files disappearing on update

I have an app that downloads several pdfs and images. It all work perfectly fine, I store information of those files in core data. My problem comes when I send out updates of the app, all the information in core data is transferred to the new version correctly but the files are nowhere to be found.

I guess I can write a routine to run when users up开发者_StackOverflowdate the app and download the files all over again. I just believe there is a better way to go by preserving the files.

Has anybody experience on this?

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You could store the files in the Documents dir, there they will be not deleted unless you remove the app from the device.