This is just under Canadian law as a general matter for income tax purposes Canadians need to maintain books and records that the CRA uses to ensure compliance with the Income Tax Act.
Part XVIII does contain specific record-keeping requirements and record retention requirements with respect to financial institutions that are required to report to the CRA. As a result, even on the termination of the agreement, part XVIII, if it stays in place, would require that the records be kept for a period, six years in the case of part XVIII, so that the CRA can undertake its enforcement and administrative duties.