When a passport is cancelled, the stamp will say: "CANCELLED. Valid visas are still valid" or something like that. Show both passports on re-entry, as your extension of stay and your re-entry permit are in the old passport.
Remember to update everywhere your passport number is used for verification, for example: Bank accounts, driver's license (you'll need to change to a new with same expiry date), certain loyalty cards, etc. You'll need to bring both passports, if you have not yet transferred your original visa from old passport to new passport; when doing that your old passport number will be written together with the visa rubber-stamp.