I upgraded to Catalina and now my Cannon printer says I have to update.

Catalina only supports 64-bit applications and printer/scanner drivers. For the specific model of your Canon device, visit the Canon website, and check if there is support for macOS 10.15 for your device with Fall 2019 released drivers and application support. If not, you have a paperweight until Canon releases updated 64-bit software, or unless the specific networked Canon device is supported by Apple's AirPrint. The latter would allow you to print without the need for Canon support software/drivers.

Go to the canon website and have a look there if there is a driver update for your printermodel