macOS shows the message below (Icon and program names differ depending on each application.):
(Message Example: ScanSnap Manager on macOS High Sierra v10.13.4)
This message means that the displayed application will need improvement for macOS. There is thus no problem on operating your ScanSnap applications, or macOS even when a message meaning like the above appears. Click the OK button, and close the message to continue operation.
Refer to "Release of 64 bit application for ScanSnap macOS software" for the update for compatibility improvement mentioned in the above message.