The quite old, but still perfectly working ADF scanner ScanSnap S300 is not supported anymore by Fujitsu. With MacOS Mojave the scanner worked very well using the ScanSnap S1300i driver. But not so with Catalina – the new ScanSnap Home software checks the connected Device IDs.
Only solution: Fujitsu wants me to buy a new Scanner although the current one is still working fine (hardware wise)…
In the end I’m using now my existing Parallels Windows 10 virtual machine to scan. On that platform the ScanSnap Manager Software is still supported – also in a 64bit version (why not on Mac Fujitsu?). You can use the newer Version from the S1500 (Download)!
Finally I am able to scan again. Without spending valuable resources into a new scanner (just because of a missing switch in a software).