There has been a long history in the evolution of the regulatory standard for child safety seats in Canada and the United States. The maximum weight that regulators allow for children in the child seats has crept up over the years. Canada has acted in a similar fashion to the United States, usually a bit after the U.S., in increasing those weights, but at the weight of 65 pounds, which I think is 30 kilograms, Canada came to the view that having children in child seats above 65 pounds was not conducive to effective safety and that they would be better off in booster seats using seat belts. The U.S. came to a different view. They have increased their maximum weight for a child in a child safety restraint system—
On April 3rd, 2017. See this statement in context.