Yes, this will require changes in the backup engine. Even though we had added extra regions following the existing naming conventions of S3, the new region has an entirely different endpoint name (ca-central-1) which we could not have anticipated as it's breaking away from the continent-compass_point-number convention they had been using so far.
Unfortunately your support request came after we released a new version of our backup software which is meant to be the last in the current branch (5.2 for Akeeba Backup for Joomla, 2.0 for Akeeba Backup for WordPress and Akeeba Solo). The next update to the backup engine will not take place for another two months when we will release Akeeba Backup 5.3.0. Until then you won't be able to use the Canada region unless, of course, you upgrade to any development, alpha, beta or Release Candidate versions we release in the meantime.
Nicholas K. Dionysopoulos
Lead Developer and Director
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