@stumccly - I assume that your ScanSnap software is the older 32-bit ScanSnap Manager. That software should work on Mojave, but will not work on macOS Catalina. To upgrade to Catalina, you must upgrade to ScanSnap Home, Fujitsu’s newer 64-bit software. Unfortunately, upgrading to ScanSnap Home will result in severe software licensing restrictions. You will have only ONE license that will work on only ONE computer. You would not be able to use the scanner for other computers in your home. If you change your computer, or if you do a “clean install” of macOS, you will be required to buy a new license, or perhaps go through the hassle of contacting Fujitsu to transfer your license.
There have been many discussions in this forum on the issue, with much criticism of Fujitsu’s license policy and its failure to support scanners prior to the iX500. Do a search for “Fujitsu” or “ScanSnap” and you will find a great deal of information.
Check the link below, with particular attention to posts 4,5 and 6 in the thread:
https://talk.macpowerusers.com/t/does-anyone-use-scansnap-home-software/8582/4
Also search for member @tomalmy. He has made many helpful posts about the ScanSnap iX500 and the new software, including several additional posts in the same thread linked above.