Thanks for the warning about Catalina.

I am a happy owner of a Fujitsu ScanSnap S1500M. Now I found this info on their website (https://www.fujitsu.com/global/support/products/computing/peripheral/scanners/scansnap/faq/s1500-catalina.html

ScanSnap S1500/S1500M Compatibility Status With macOS 10.15 Catalina:
The ScanSnap software (*) is not available on macOS 10.15 Catalina. To keep using your ScanSnap, use it on the current version of macOS. When you >update your macOS, please consider purchasing a ScanSnap that is currently available.
Details
The ScanSnap software (*) is not available on the macOS as it does not support any 32-bit applications.（No further updates will be provided to the ScanSnap software.）
If you will use macOS 10.13 or earlier, you can keep using ScanSnap S1500/S1500M on the OS.
When you use macOS 10.14 or later, please consider purchasing a ScanSnap that is currently available.

These things make me angry ...