We store all your flashcards on our servers where we keep them safe, serve them mojitos and tapas, and let them rest before your next review session! Basically, you do not need to download your cards, if you have an active subscription you can always review them in the app.
If you are a retail subscriber (versus a backer from one of our two crowdfunding campaigns) and you have decided to switch your language, at this point, it is not possible to download your previous language's flashcards, however, we are considering implementing an option to export data in the future.