This is exactly what says on the letter about OWP:
Please note that this letter is a notification only. It is not valid for travel and is not a permit
allowing you to stay in Canada.
Document to travel to Canada or re-enter:
A study or work permit is not a travel document. To allow you to travel to or re-enter Canada
by air only, we have issued you an Electronic Travel Authorization (eTA) when we issued your
permit extension. Your eTA is linked to the passport that you used to apply for your permit
renewal. You must travel with this same passport. If you get a new passport, you will need to get
a new eTA.