Then no matter what the app is offering, I doubt you'll be able to purchase it and activate it.... But if you did want to try, then I'd buy it now. The first thing they do in the event of a claim is check the flight data so if you try and purchase it after you crash, they'll decline it rregardless... But as said, I doubt youl'll get it activated anyway given how long you've had it flying.
Cheers
Ian