I've been participating in this thread for almost 4 years.
I've been to Australia 2 or 3 times during that time. I usually brought my Mavic 2 Pro but never found a good time to fly or there were some issues with the drone all the time, like...
So up to the owner to apply which sticker thinks applies?
Once they put a C1 sticker over the C0 sticker, there's no going back, unless DJI would send you more C0 stickers?
For both the Mini 4 and 5 Pro the C0 is a sticker. The C1 is also a sticker, though if I remember correctly, there was a sticker in the battery compartment of the Mini 4 that also needed to be replaced and photo’s taken to send to DJI.