I'll guess that if Canon hasn't released a Mojave compatible driver for your Pixma by now, it's probably a dead issue.
Why don't you contact them and see what they've got to say about it? Will do. If I learn anything positive, I'll post
ryck
"What Were Once Vices Are Now Habits" The Doobie Brothers
iMac (Retina 5K, 27", 2020), 3.8 GHz 8 Core Intel Core i7, 8GB RAM, 2667 MHz DDR4
OS Sonoma 14.4.1
Canon Pixma TR 8520 Printer
Epson Perfection V500 Photo Scanner c/w VueScan software
TM on 1TB LaCie USB-C
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