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.
Just occurred to me... Was that with the CUPS driver? And if not, you ought to try it.
The new Great Equalizer is the SEND button.
In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire
