The Step-Down Power Supply is now available in hardware version 1.3. It is reverse polarity protected on the input as well as output connector and you can also accidentially confuse the input with the output.
In version 1.2 and below connecting 6-24V to the output connector (interchanging the black and green connector) could result in a catastrophic failure of a whole stack. In version 1.3 the Step-Down Power Supply is now protected against this failure mode.
Because of production delays the Step-Down Power Supply was out of stock for ~3 weeks. All of the backorders are now shipped and everyone that was waiting for a Step-Down Power Supply to be delivered will already receive the new version 1.3!