The last update on the mobile app included several challenges that were updated. Most noticeably a lot of the "bet max" challenges have disappeared and were replaced with others. There were a couple of challenges that I had previously given up on, but after the update a couple of them stated in the description "challenge complete". After making one bet on that challenge (lowest possible), the screen popped up saying challenge complete, and I collected the chips. So glad to see they are updating the game based on feedback and history.