Next February, the U.S. treasury will issue a new style $100 bill.
The reason for this 3 years overdue, high tech bill, is to thwart counterfeiters, like North Korea.
There's 6.5 billion $100 bills currently in circulation and 66% are out of the country.
Fortunately the old bills are still good, so I won't have to lug all those cardboard boxes in the attic to the bank.
link