You may see the following message when opening an installer, or launching Revoice Pro software on macOS 10.15 Catalina or higher:
"________ can't be opened because Apple cannot check it for malicious software."
To avoid this message right click (or control-click) on the installer (or Revoice Pro 4 application icon,) and select Open from the context menu.
This will show you a new option to open the installer or app, not available with a normal double-click or command+o.
Your system will remember your choice to ignore the warning, and not display the message for the same app or installer again.