On the old card, certs issued before May 1 2019 will be valid for any hotel. After that, they will be capped at 40K, same as the new card.
https://thepointsguy.com/news/ihg-se...-through-2019/

But... There's no need to cancel the old before applying for the new. You can hold both and earn 2 free nights each year (for 2 annual fees).