Look at the sticker under the JM40M01. If it says REV: B or higher, you need the . If REV: A , use v2.1 .
A "repack" usually includes the core driver files along with configuration tools. If you are looking for a simplified installation: Label Printer Utility : Download the Label Printer Utility citizen label printer jm40m01 driver repack download
Do you need help with for multiple computers? Look at the sticker under the JM40M01