I've seen many times "you can choose to preserve pricing for past subscribers" but no where does it say what I need to do to choose this. I have a price increase ready to press go on but I want to ensure that my past subscribers are locked in at the price they joined at and they aren't charged more next month.

Hi! We are wanting to do this too but the person who is helping us with our app says this isn't possible. How do we preserve the old members prices?