We've pushed this update out to the app stores! To see it in action, please get the update and install it.
The Grand Chest now uses controlled random, or "pity mechanics," which improve chances of high value rewards until they happen. (We are also adding another level to the Grand Chest. Level 12 will now be the first time the Grand Chest upgrades (rares are removed from the possible options in the Grand Chest at that point). Hero level 28 will be the next time the chest odds undergo a change to weight the results more toward Legendary and Mythicals.)
We will start everyone off on this new Grand Chest system by using the “pity mechanics” -- as if you had opened twenty chests without getting any Mythicals. So, for example, if you are over hero level 12, you will see a +2% improvement to your base chances to get Mythicals (for a total of 5%).
In addition to improving your chances per rarity as you open chests, you will also see improving chances to unlock the bigger piles of Legendary and Mythical gems, if your first pile is the small one. These two pity boosts are separate, so if you get the second to smallest possible pile of Mythicals, your chance to _get_ them will be reset to the base chance, but you’ll still have an improved chance to get a bigger stack of them.
As with many things in Solgard, this will make much more sense when you look at the chest in the game