Some useful tips for anyone applying for CNCC in 2021.
(1) Fingerprints : if you are applying from Canada, you can use any RCMP accredited fingerprint company to take your prints. Try to find one that do ink and roll, HKPF prefers ink and roll but will accept live scan if you have no other choice. (I provided both ink and live scan, they took the ink one). Make sure there is an official stamp from the company on your form.
(2) If you have a friend/relative in HK that can hand in your application in person, do that so that you can get your receipt from the police right away. Also you can know right away if there is any problem with your application (e.g. missing information). If you don't know anyone in HK that can help you, then you have to send in the applications by mail, just double check on the checklist as there will be a few weeks turn around time if your application is not accepted.
(3) If you are going to have a representative to hand in your application, you need to make an appointment with the HKPF online booking system. You will likely find that the earliest available date is at least 3 weeks away, book it anyway because you can modify the appointment later. I had success re-booking my appointment to an earlier date by checking the booking site everyday during HK night time (after 9pm) because there are always some cancellations every week.
(4) Since April 2021, all CNCCs will be sent to the Canadian Consulate in Hong Kong due to the pandemic disruption of air mail services. CNCC should be processed within 4 calendar weeks, you should add another 2 weeks for the Canadian consulate to upload your CNCC. This may change as soon as the air mail service get back to normal in Hong Kong and around the world.