I dropped the ball on this when we entered a week ago, had nothing and there was zero comment nor consequence. YMMV.
I missed last month also. Didn’t know until in the line with everybody who had their phones or printed copies at the ready. Immigration agent advised to proceed into customs and complete. We spotted our bags and completed the process on an iPhone (no problem with signal) with the help of an official who said we could do two pax in one filing.
Walked to customs, showed the phone to the guy, pay $10 per person, finished.
I’ve got it as a reminder for our group next week. I don’t want to do it again while standing in-line, shuffling and dragging luggage!