Yes, this is normal. Old series of banknotes are routinely withdrawn from circulation at the direction of the Bank of Canada. This is done for several reasons. When the banknotes in circulation are more-or-less all the same current series, it keeps things simple for banknote users. It is also important in the constant fight against counterfeiters.

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BWJM
Member of CPMS, RCNA, ONA, ANA, IBNS, WCS.
President, IBNS Ontario Chapter.
Treasurer, Waterloo Coin Society.
Show Chair, Cambridge Coin Show.
Fellow of the Ontario Numismatic Association.