[infensus]

To me it seems like Duolingo is doing a lot of A/B testing, but in a really weird manner. I was also annoyed by not having access to language tips in the mobile app, while they were available in the browser. I also have a friend, for whom the whole app changed after reinstalling: they didn't have the heart system before, now it was on; the gem system changed to gem of a different value, while prices in the store stayed the same. They always had notes on every platform in every language though.