Announcement on.com
http://announcements.ebay.com/2016/01/add-product-identifiers-to-non-compliant-listings-and-get-a-2-...
As promised, we want to remind you that, starting the week of February 29, product identifiers will be required to list or relist in a number of additional categories. If you’re a seller who lists in these categories, we encourage you to find out if your listings are missing these identifiers—and add them to your listings now, before the requirement takes effect.
More info - http://pages.ebay.com/sell/item_specifics/product_identifiers.html#csa
I don't see an announcement on .ca so I don't know if this will apply to listings originating on .ca as well but I have a feeling that it will.
You should read the full announcement as there is also info about receiving a credit if you update listings that meet a specific criteria. It has to be done by the end of this month but I didn't notice the announcement until today.