The app has always required an account before using it. It's easy to forget because most of the time the app logs you in automatically. You may have used your Apple or Facebook or one of your other emails.
Please make sure you don't create a new account when you've been using the app for a while. If you do this your existing data will NOT load. This is because your data is associated with your original account.
When you create an account or login, your session is saved for you. If you get logged out or access the app from a new phone you'll need to know how you originally logged in.
If you need help finding your existing account please open a chat with me.