In 1982, the coins went from a round edge to a 12 sided edge. The composition of the coins has changed a lot over the years, with steel replacing copper as the primary metal.
The portrait of the Queen would change several times over this time period. In 2003, there were two different portraits of the Queen - one a continuation of the previous series, and a new, modern portrait where she has no tiara in her hair.
In 2012, the Canadian government discontinued the penny as part of its currency.