National Day for Truth and Reconciliation on September 30th has been incorporated into the definitions of prescribed holidays for which deadlines are deferred in the Trademarks Regulations, Patent Rules and Industrial Design Regulations.
This is now available in the Canada Gazette. The RIAS says in part:
The Patent Rules, the Trademarks Regulations and the Industrial Design Regulations, as currently drafted, do not include the National Day for Truth and Reconciliation observed on September 30 as a day for which the Canadian Intellectual Property Office is closed and deadlines are automatically extended. Without amendments to these regulations, the National Day for Truth and Reconciliation will be the only statutory holiday not identified. As the Office would be officially closed on September 30, this could potentially cause confusion to stakeholders due to the day not being listed.