Build a simple app, using either ReactJS or React Native, which retrieves address and transaction information from the BTC blockchain. It also allows a user to subscribe for changes to specific hashes. Each subscribed hash should generate a notification on the UI. Furthermore, the user should be able to select in which currency the values should be displayed (USD, EUR or BTC).
Bonus points will be awarded for the implementation of a functionality that retrieves the top 5 searched addresses and transactions.