Descriptive Alerts is now Wyze Stories.
If you were using Descriptive Alerts, your cameras carry over automatically and you'll now see Wyze Stories in the Events tab and under Wyze Intelligence in your account. There is nothing you need to buy or set up.
If some of your cameras had Descriptive Alerts turned off, those cameras stay off. The app will show you which cameras are eligible so you can turn them on whenever you like.