That may be true in the US, and there may be legal ways to get the US government or US banks to exchange old notes for new notes, but good luck outside of the U

That may be true in the US, and there may be legal ways to get the US government or US banks to exchange old notes for new notes, but good luck outside of the US finding someone who will trade old US currency for something of value today, or tomorrow for that matter. For instance, I live outside the US and I have roughly $300 in older US $100 bills that was given to me and my wife as a gift for our wedding. No over-the-counter currency exchange or bank will accept the notes. I could probably find someone here to trade me something for the notes, but the effort/hassle is probably not worth it for such a low number of bills.