I'm currently running PDFtk Server successfully on macOS Sierra without issues with @Sid Steward's update pkg file found here: PDFtk Server on OS X 10.11.
Yet I have reservations moving to High Sierra because the new Apple File System (APFS) is default on this release, therefore I don't know this will break PDFtk server.
Has anyone got PDFtk Server running correctly on macOS High Sierra 10.13? If not what are the issues?