From the announcement:
The new dice are one of the new surprises in the upcoming starter sets.
Dust dice no longer have blanks on them, though you can still use the old dice instead of the new ones. We did not want blank sides on the dice. What does this mean in the game? Each die now has three symbols: a faction symbol, a shield symbol and a target symbol. Your unit symbol always is a success when rolling no matter what.
The other symbols are come into play when the rules would have you rolling for blanks. Instead of rolling for blanks with the new dice you now roll your faction symbol plus one of the other symbols depending on what you are rolling for, if you are rolling in a defensive situation then you add the shield and for attacking situations you add the targets.
Both the new and the old dice are covered in the new rule book so don’t worry- your old dust dice are still perfectly valid.