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?

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