I've a Canada Work Permit and I'm currently in India (returned to take my family). I've IRCC's authorization mail for my wife and kids who hold approved visitor Visas - however this Authorization was issued back in May 2020. They were unable to travel and all of us are planning to travel together in January/Feb. My letter does not show any validity dates and so I assume I can use the same letter. Also, I'll be boarding the flight with them. Please let me know if I need to apply for a fresh Authorization from IRCC