Another titbit of exciting news has just been announced today. For the first time of the history of 3DS, you will be able to personalise your Home Menu!
— Nintendo UK (@NintendoUK) August 29, 2014
You can change the appearance using different themes which change the backgrounds and folder icons, and you can also add sound effects and music. All this will be available through a system update this October!
That is currently all we know at this point, but will post updates once a detail explanation is available!