Just went to their facts page..looks like another new feature: masteries (or did i miss something before?

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The Masteries are unlocked at level 15. When any of the production buildings is tapped you will see 3 empty star slots above the building’s name. Each star is based on total production time (measured in hours). As an example - to get the first star in the Bakery, you need to have produced 100hrs worth of products from that machine. The next star requires even more usage of the production building. The reward for collecting each star is a permanent increase in the products attributes - 1 star: products from the machine worth x-amount % more coins in car orders, 2 stars: products from the machine worth x-amount % more XP in car orders, 3 stars: building produces products x-amount % faster + a visual reward to the building. You are also able to pay diamonds to reach the next star faster. The price of the skip is based on how many hours are left to collect the next star.
GC: *joyc* (including stars) - level 42