We've added (and fixed for those who previously updated) a new feature to the game:
Daily and Weekly Quests.

Check out new Quests menu hidden behind the pin icon. Completing each one will reward you with Bolts, and if you have enough Bolts the task progress bar will fill up and you will receive rewards for reaching new milestones. When the time runs out your progress and rewards will be reset and you'll be able to complete new ones again in the following days.