Nintendo will be adding a new character to Super Mario Run on September 29th as Princess Daisy will join the game's roster to run through the game's levels with. The iTunes App Store showed a preview of a new level and a new mode in which the red-headed princess is front and center. Daisy will come with a new special double jump ability, which will make old levels new again as you can probably speed run them faster with her powers and get ahold of coins that some players just haven't been able to snag.
But Daisy is not an automatic character. You'll need to rescue her in the new mode "Remix 10", which has you completing a series of mini-levels created out of already existing levels within Super Mario Run, and you'll need to do them under the clock. According to IGN, you'll have multiple levels of completion based on a rainbow color scale, which we're guessing will go from green to yellow so you can unlock Daisy when you have yellow across the board. The update itself will include a new world with various new enemies you'll need to contend with, but of course, you'll need to unlock those as well by beating all of World 1-6.