This solution describes the differences between v1 and v2 printers for our HD series. The difference is in the mounting of the extruder motors on the back of the printer. You will need to know whether your printer is a v1 or v2 when upgrading to a JR2x (Dual) hot end.
>>>HD Series v1
v1 printers have the extruder motor assembly attached directly to the back panel. They are located in the center of the back panel.
>>>HD Series v2:
v2 printers have the extruder assembly mounted to the top acrylic panel. They are located in the upper corners of the back panel.