Anyone millennial-aged or older is likely able to remember a whole spate of different  Canadian bank notes as they have evolved over the years, but apparently, some past iterations are so dated and rare that younger generations can't believe they're real.

One customer at a coffee shop in Sudbury was taken aback when she learned this lesson this week after, per the CBC, a staff member very closely examined an older bill she used to pay for her drink before eventually refusing to take it.

The note in question was a classic $5 from the Birds of Canada series that most millennials will remember from childhood — and for those who don't, the fiver is shades of royal blue with the face of Sir Wilfrid Laurier on the front and a belted kingfisher on the back.

The series, which was the last to include $2 and $1,000 bills (which are no longer legal tender), started circulation in 1986, and it wasn't until 2001 that a new design, the Canadian Journey Series, came out.

While the old currency type is still legal tender, the staff member was clearly unfamiliar with the bill given its age and theirs.

And, though the CBC reported that the mistake was corrected the next day when an older manager confirmed the cafe should have accepted the bill, businesses are actually within their right to turn down any older notes — or any type of currency generally — if they so choose.

"It is up to the seller to determine the method of payment accepted for transactions. No law requires anyone to accept bank notes or any other form of payment to settle a commercial transaction," a representative from the Bank of Canada confirmed to blogTO on Tuesday.

They also clarified that though all bills are referred to as "legal tender," this is a technical term simply meaning that it is "the money approved in our country for paying debts" and does not force anyone to accept that form of payment.

"How you pay for a good or service (by cash, credit card, or in some other manner) is a matter of private agreement between you and the seller, and must be acceptable to both," they continued.

the kingfisher $5 in the Birds of Canada series was the best banknote canada has ever produced and will never be improved upon@bankofcanada https://t.co/uyCAOx4dkZ pic.twitter.com/urxAwdPQcZ

— Lukas Neville (@lukasneville) January 9, 2020

Over the pandemic, for example, many businesses chose to go cashless and have continued that way for the benefits, which include not having to worry about the safety issues that come with holding large amounts of cash on site, and not having to maintain enough change or a float.

But kids not recognizing bills that came before the nation's new plastic money is indeed a new reason that is bound to make many feel pretty darn old if and when it happens to us.

You can always take older bills to a bank or send them to the Bank 0f Canada to have them swapped for new ones.