I suggest that you upgrade a clone of High Sierra to Mojave and see what happens. I upgraded my Super Duper backup to Mojave and neither the printer nor the scanner worked. The Canon software kept returning the caution "Printer is not attached" and my MP Navigator EX scanner software didn't even load its windows. Oh well.
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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