Have never had a problem with new design US bills in Costa Rica. They seem to be very aware of changes in US currency and accept them as easily as the old design.
I must temper that by saying the only time I deal in US currency is when I am changing the monthly amount required to maintain my residency so it is done at a bank. All my transactions with merchants is done in colones.
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Pura Vida

Only Irish coffee provides in a single glass all four
essential food groups:
alcohol, caffeine, sugar and fat.
Alex Levine
