Drops topics have been organized under Learning Units to offer a more seamless learning experience within the app. To access the Units, please log into your account and tap on the Explore button. You will be presented with the list of the available Categories that include the related Topics.
Since some words and phrases have been moved to different topics, topic progress will change. The good news is that none of your progress disappears, it's just added to the topic where the word you've learned or mastered now belongs.