Apple is expanding the capability of its In-App Purchase framework with a new retention messaging API. This means, for the first time, developers will be able to show offers to users when they go to cancel a subscription in the global Subscriptions screen inside the Settings app. Apps will be able to show a simple static message, display dynamic progress based on the user’s app state, or present a special offer to try and dissuade the user from cancelling their payment altogether. more…