Request Letter for Passport Photocopy -- No longer have very old expired passport, what to do?

[fizban]

Like many, I have received a request letter for all pages of all passports valid in the 5 year eligibility period -- My eligibility period is Jan 1, 2016 to Dec 31, 2020, but I began my physical presence in March 2016.

My current passport has been valid since mid-January 2016 but I no longer have the very old passport which was valid for only the first couple of weeks of January 2016 -- the very beginning of the eligibility period. It has either been lost, or perhaps it is somewhere deep in storage in my parent's place in my home country.

Since I began my physical presence in March 2016, I am not claiming any days from early January 2016 anyway. I have over 1600 physical presence days so even if for some reason those days are disqualified, I am well above the 1095 day requirement.

Does anyone have any experience with how CIC will react if I cannot produce this very old passport?

Edit: According to https://www.canada.ca/en/immigration-refugees-citizenship/services/coronavirus-covid19/citizenship.html#s3, it says "Don’t travel to another city or country to get the supporting documents" -- so even if the old passport is at my parent's home, I should not travel to get it.