No, under the current pricing structure, Chronos Planner is being offered as a one-time Universal Purchase, meaning you will only have to purchase the app once on any of your devices and you will be able to continue to use it without any additional costs. All future updates to the app will be included at no further cost to you.
It is possible that we may introduce a premium subscription in the future for features we would like to include but would incur a monthly recurring operating cost. In this case, all existing features already included in the Chronos Planner app will be unaffected, and you will not need to subscribe in order to access existing functionality. Details of a premium subscription will be shared with our newsletter subscribers closer to the launch date.