If you have both “landed” you have become permanent residents and should have received PR Cards. Your PR Card is important whereas your COPR is not; you should put your COPR in a safe place as you do not need to use it for anything. You can ignore the expiry date on your COPR if you have landed already.
You need to renew your PR Card every five years when it expires. At that point, you need to have met the requirements of permanent residence but, if you don’t, your status has to be revoked, it will not just expired.