Is it possible to make a paid issue become free? Will it cause any problems for people that have paid for it, if it is now free? Do I just remove the in app purchase then change the folio to free?
Yes, you can modify paid content to free, i've just "switch off" the in-app purchase item in iTunes Connect and updatet folio in Folio Producer as free and it worked as a charm.
I think that you can convert free to paid, but i didn't tested this personaly (i will appreciate your experience, because we will do this in few months for one project)
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